Cutis

Fragrances are complex organic compounds that are sufficiently volatile to produce an odor—most often a pleasant one—or at times intended to neutralize unpleasant odors. They can be further divided into natural fragrances (eg, essential oils) and synthetic ones. Fragrances are found in abundance in our daily lives: in perfumes; colognes; lotions; shampoos; and an array of other personal, household, and even industrial products (Table). These exposures include products directly applied to the skin, rinsed off, or aerosolized. A single product often contains a multitude of different fragrances to create the scents we know and love. To many, fragrances can be an important part of everyday life or even a part of one’s identity. But that once-intoxicating aroma can transform into an itchy skin nightmare; fragrances are among the most common contact allergens.

Given the widespread prevalence of fragrances in so many products, understanding fragrance allergy and skillful avoidance is imperative. In this review, we explore important aspects of fragrance allergic contact dermatitis (ACD), including chemistry, epidemiology, patch test considerations, and management strategies for patients, with the goal of providing valuable clinical insights for treating physicians on how patients can embrace a fragrance-free lifestyle.

How Fragrances Act as Allergens

A plethora of chemicals emit odors, of which more than 2000 are used to create the fragranced products we see on our shelves today.¹ For many of these fragrances, contact allergy develops because the fragrance acts as a hapten (ie, a small molecule that combines with a carrier protein to elicit an immune response).² Some fragrance molecules require “activation” to be able to bind to proteins; these are known as prehaptens.³ For example, the natural fragrance linalool is generally considered nonallergenic in its initial form. However, once it is exposed to air, it may undergo oxidation to become linalool hydroperoxides, a well-established contact allergen. Some fragrances can become allergenic in the skin itself, often secondary to enzymatic reactions—these are known as prohaptens.³ However, most fragrances are directly reactive to skin proteins on the basis of chemical reactions such as Michael addition and Schiff base formation.⁴ In either case, the end result is that fragrance allergens, including essential oils, may cause skin sensitization and subsequent ACD.^5,6

Epidemiology

Contact allergy to fragrances is not uncommon; in a multicenter cross-sectional study conducted in 5 European countries, the prevalence in the general population was estimated to be as high as 2.6% and 1.9% among 3119 patients patch tested to fragrance mix I (FMI) and fragrance mix II (FMII), respectively.⁷ Studies in patients referred for patch testing have shown a higher 5% to 25% prevalence of fragrance allergy, largely depending on what population was evaluated.¹ Factors such as sociocultural differences in frequency and types of fragrances used could contribute to this variation.

During patch testing, the primary fragrance screening allergens are FMI, FMII, and balsam of Peru (BOP)(Myroxylon pereirae resin).⁷ In recent years, hydroperoxides of linalool and limonene also have emerged as potentially important fragrance allergens.⁸ The frequencies of patch-test positivity of these allergens can be quite high in referral-based populations. In a study performed by the North American Contact Dermatitis Group (NACDG) from 2019 to 2020, frequencies of fragrance allergen positivity were 12.8% for FMI, 5.2% for FMII, 7.4% for BOP, 11.1% for hydroperoxides of linalool, and 3.5% for hydroperoxides of limonene.⁸ Additionally, it was noted that FMI and hydroperoxides of linalool were among the top 10 most frequently positive allergens.⁹ It should be kept in mind that NACDG studies are drawn from a referral population and not representative of the general population.

Allergic contact dermatitis to fragrances can manifest anywhere on the body, but certain patterns are characteristic. A study by the NACDG analyzed fragrance and botanical patch test results in 24,246 patients and found that fragrance/botanical-sensitive patients more commonly had dermatitis involving the face (odds ratio [OR], 1.12; 95% CI, 1.03-1.21), legs (OR, 1.22; 95% CI, 1.06-1.41), and anal/genital areas (OR, 1.26; 95% CI, 1.04-1.52) and were less likely to have hand dermatitis (OR, 0.88; 95% CI, 0.82-0.95) compared with non–fragrance/botanical-sensitive patients.¹⁰ However, other studies have found that hand dermatitis is common among fragrance-allergic individuals.^11-13

Fragrance allergy tends to be more common in women than men, which likely is attributable to differences in product use and exposure.¹⁰ The prevalence of fragrance allergy increases with age in both men and women, peaking at approximately 50 years of age, likely due to repeat exposure or age-related changes to the skin barrier or immune system.¹⁴

Occupational fragrance exposures are important to consider, and fragrance ACD is associated with hairdressers, beauticians, office workers exposed to aromatherapy diffusers, and food handlers.¹⁵ Less-obvious professions that involve exposure to fragrances used to cover up unwanted odors—such as working with industrial and cleaning chemicals or even metalworking—also have been reported to be associated with ACD.¹⁶

Patch Test Considerations

Patch testing is essential to confirm fragrance allergy and guide treatment, but because there are so many potential fragrance allergens, there is no perfect patch test strategy. In a standard patch test series, the most important screening allergens are considered to be FMI, FMII, and BOP; tested together, they are thought to detect a large proportion of cases of fragrance allergy. Strikingly, in a large European study (N=1951), patch testing with the fragrance markers in the baseline panel failed to detect more than 40% of cases of allergy compared to testing with 26 individual fragrance allergens.¹⁷ Other studies have reported that a smaller proportion of fragrance allergies are missed by using baseline screening allergens alone.^18,19 Limonene and linalool hydroperoxides also are potentially important fragrance allergens to consider adding to the patch test panel, as unoxidized limonene and linalool commonly are used in many products and could theoretically undergo auto-oxidation under use conditions.⁸ However, because of the high number of irritant, questionable, and potentially false-positive reactions, the Information Network of Departments of Dermatology has recommended against adding these hydroperoxides to a standard screening tray for patch testing.²⁰ It must be remembered that a positive patch test to a fragrance does not necessarily represent ACD unless the patient has a clinically relevant exposure to the allergen.²¹

In patients who test negative to the baseline ­fragrance-screening allergens and in whom a high degree of suspicion remains, further testing with supplemental fragrance allergens (commercially available from patch test suppliers) is warranted.¹⁷ The thin-layer rapid use epicutaneous (T.R.U.E.) test (SmartPractice) includes FMI and BOP but not FMII or linalool or limonene hydroperoxides. More comprehensive patch test panels are available that include additional fragrances, such as the North American 80 Comprehensive Series and the American Contact Dermatitis Society Core Allergen Series.^22-24 It is important to remain vigilant and consider expanded patch testing if patients initially test negative but suspicion remains.

Furthermore, patch testing with the patient’s own products is an important consideration. Uter et al²⁵ evaluated patch testing using patients’ perfumes, deodorants, and shaving lotions, and approximately 41% (53/129) of patients who tested positive to their own product tested negative for fragrance-screening allergens. Although it can be difficult to ascertain which exact component of a commercial product is the culprit, a positive patch test may still provide clinically relevant information for patients and treating physicians. In cases of questionable or weak-positive results, repeat testing or repeated open application tests can help re-evaluate suspected products.

Cross-reactivity should be considered when patch testing for fragrances. Atwater et al¹⁰ found that cross-reactivity between FMI, FMII, and BOP was common; for instance, approximately 40% of patients testing positive to FMII or BOP also had positive reactions to FMI (522/1182 and 768/1942, respectively). Understanding this concept is important because in some cases (as detailed below) patients will need to avoid all fragrances, not just the ones to which they have previously been exposed, given the limitations on fragrance labeling in the United States. However, this may change with the Modernization of Cosmetic Regulation Act of 2022.²⁶

Avoiding Fragrances: Improving Patient Education and Outcomes

Once a relevant contact allergy to fragrance is established after patch testing, successful avoidance is critical but challenging, as there are numerous potential pitfalls. Missing just 1 hidden source of fragrance exposure will often be the difference between success or failure. Dermatologists play a crucial role in guiding patients through the intricate process of identifying and avoiding potential allergens.

Optimal Safety: Embracing a Fragrance-Free Lifestyle

For fragrance-allergic patients, it generally is safest to completely avoid fragrance.

First, if a patient only shows positive patch-test reactions to fragrance screening mixes (and not to the particular fragrances in these mixes), there is no way to be certain which fragrances the patient needs to avoid.

Second, even if specific fragrance allergens are identified, numerous chemically related fragrances to which the patient may be allergic are not commercially available for patch testing. One review provided evidence of 162 fragrance allergens that have been documented to cause contact allergy.¹ Dermatologists generally patch test to screening mixtures and/or the 26 fragrance chemicals required on labels in European products (European Directive fragrance).²⁷ Therefore, there are more than 100 known fragrance allergens that are not routinely tested to which patients could be allergic.

Third, certain fragrances, such as limonene and linalool, are found in many products with fragrance, and it is difficult to find products without these substances. Limonene and linalool themselves are not potent allergens; however, upon air exposure, they may auto-oxidize to hydroperoxides of limonene and linalool, which are increasingly common positive patch tests.¹⁹

Additionally, patients should be advised that many products labeled “fragrance free,” “unscented,” or “free and clear” are not truly fragrance free, and patients should not choose products based on these claims. There are no legal definitions for these claims in the United States, and industries are allowed to choose the definition they prefer. Numerous products labeled “unscented” use this term to indicate that the product had an odor, the company used a masking fragrance to hide the odor, and then the product can be considered unscented. In many holistic stores, most products labeled “fragrance free” are only free of artificial fragrances but contain essential oils. Of the 162 documented fragrance allergens, 80 are essential oils.⁶ Essential oils are perceived to be safe by the vast majority of the population because they are viewed as “natural” and “unprocessed” sources of fragrance.²⁸ However, numerous allergenic terpenes have been discovered in essential oils, including functionalized variations of alcohols (eg, geraniol, bisabolol) and aldehydes (eg, citronellal).⁶ Essential oils also consist of nonterpenic compounds produced through the phenylpropanoids pathway, including eugenol and cinnamaldehyde. One review showed that most essential oils contain one or more European Directive fragrance.²⁹ Therefore, many products labeled “unscented,” “fragrance free,” or “natural” are not free of fragrance and may be unsafe for fragrance-allergic patients.

Although not required, manufacturers sometimes voluntarily list one or more of the 162 currently identified fragrance allergens on product labels. Also, there are more than 50 potentially allergenic essential oils that can be listed on labels by their common names or by genus or species. In addition, there are synonyms for fragrance, such as aroma, parfum, perfume, and scent. Therefore, there are several hundred different ingredient names on labels that indicate the presence of fragrance, and patients are very unlikely to successfully identify fragrance-free products by trying to read product labels on their own.

Lastly, in the United States product labels only require products to state that they contain “fragrance” and do not mandate the listing of specific fragrances. If a patient is allergic to a specific fragrance, there is no way to determine if that fragrance is present in these products. This will change with the enactment of Modernization of Cosmetics Regulation Act of 2022, which empowers the US Food and Drug Administration to require manufacturers to disclose many, but not all, fragrance allergens on the labels of cosmetic and topical products.²⁶

For all these reasons, patients should be advised to use a medical database to choose safe alternative products instead of trying to read labels themselves to avoid fragrance. The American Contact Dermatitis Society’s Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) is designed to identify safe alternative products for patients with contact allergies. When CAMP is programmed to avoid “fragrance,” it will list only “safe” products free of all fragrances found in a comprehensive fragrance cross-reactor group.³⁰ This customizable database is available as an application that can be downloaded onto a patient’s mobile device. Fragrance-allergic patients should be encouraged to use the CAMP application or other similar applications (eg, SkinSAFE)(https://www.skinsafeproducts­.com/) to find all the products they use.

Potential Pitfalls in Fragrance Avoidance

Most physicians, even dermatologists, will not know which products on the market are fragrance free from a contact allergy standpoint. Patients should instruct their physicians to use the allergen-avoidance application of choice whenever recommending new topical products, whether prescription or nonprescription. In 2009, Nardelli and colleagues³¹ found that 10% of topical pharmaceutical products contained a total of 66 different fragrance substances.

Individuals who are allergic to fragrance also can react to fragrances used by close contacts (ie, consort dermatitis).³² Therefore, fragrance-allergic individuals who do not improve after changing their personal products should consider urging their spouses or significant others to choose their personal care products using an allergen-avoidance application. Also, physical contact with pets can cause reactions, and the use of a fragrance-free pet shampoo is recommended. Additionally, allergic individuals who are providing care for small children should select fragrance-free products for them.

Some of the most heavily fragranced products on the market are found at hair salons. One exposure to an allergen often can keep patients broken out for up to 4 weeks and occasionally longer, a typical frequency for salon visits—even if the individual is taking great care to avoid fragrance at home. Patients should be instructed to bring their own shampoo, conditioner, and styling products to the salon. These patients also should bring safe moisturizer and nail polish remover for manicures. Additionally, aromatherapy used in most massages can cause flare-ups, and it is recommended that allergic patients purchase fragrance-free massage oil to bring to their sessions.

Fragranced soaps and cleansers can leave a residue on the palmar surface of the hands and fingers. This residue may not meet the threshold for causing a reaction on the thick skin of these surfaces, but it is sufficient to passively transfer fragrance to other more sensitive areas, such as the eyelids. Passive transfer of fragrance can be a major source of allergen exposure and should not be overlooked. Allergic patients should be instructed to bring safe hand cleansers to friends’ houses, restaurants, or work.

Airborne fragrances in a patient’s environment can reach sufficient concentration to cause airborne contact dermatitis. In one case report, an Uber driver developed facial airborne ACD from a fragrance diffuser in his vehicle and his condition improved upon removing the diffuser.³³ Therefore, patients should be instructed to avoid fragranced diffusers, scented candles, room deodorizers, incense, and wax melts.

Fragrance in household products also can be an issue. Fragrance-allergic patients should be instructed to choose fragrance-free cleaning products and to avoid fragranced wipes on surfaces that may be touched. In addition, they should be instructed to use fragrance-free laundry products. It is not required for household products in the United States to list their ingredients, and the majority do not have complete ingredient lists. Therefore, it is imperative that the patient use an allergen-avoidance application that identifies products that have full ingredient disclosure and are free of fragrance.

For individuals who enjoy perfume and/or cologne, it may be possible for them to resume use of these products in some cases after their condition has fully cleared with complete fragrance avoidance. They should avoid spraying products into the air or applying them directly onto the skin and should instead dip a cotton swab into the perfume/cologne and dab a small amount onto their clothing. This technique can sometimes satisfy the patient and improve compliance.

If a patient who is allergic to fragrance does not clear after 6 weeks of complete fragrance avoidance, it is worth considering systemic contact dermatitis due to ingestion of fragrance-related substances in foods.³⁴ A large number of fragrance materials also are food flavorings. For patients allergic to a specific fragrance(s), systemic avoidance needs to be specific to the allergen, and the Flavor and Extract Manufacturers Association’s flavor ingredient library is most helpful (https://www.femaflavor.org/flavor-library). If the patient is allergic to the complex mixture BOP, a balsam-free diet can be attempted.^35,36

Final Thoughts

Dermatologists must equip themselves with the knowledge to educate fragrance-allergic patients on proper avoidance. The multifaceted nature of fragrance avoidance requires a personalized approach, combining label scrutiny, utilization of a safe-product application, and tailored recommendations for specific situations. By guiding patients through these complexities, dermatologists can empower patients to manage their fragrance allergy and enhance their quality of life.

Fragrances are complex organic compounds that are sufficiently volatile to produce an odor—most often a pleasant one—or at times intended to neutralize unpleasant odors. They can be further divided into natural fragrances (eg, essential oils) and synthetic ones. Fragrances are found in abundance in our daily lives: in perfumes; colognes; lotions; shampoos; and an array of other personal, household, and even industrial products (Table). These exposures include products directly applied to the skin, rinsed off, or aerosolized. A single product often contains a multitude of different fragrances to create the scents we know and love. To many, fragrances can be an important part of everyday life or even a part of one’s identity. But that once-intoxicating aroma can transform into an itchy skin nightmare; fragrances are among the most common contact allergens.

Given the widespread prevalence of fragrances in so many products, understanding fragrance allergy and skillful avoidance is imperative. In this review, we explore important aspects of fragrance allergic contact dermatitis (ACD), including chemistry, epidemiology, patch test considerations, and management strategies for patients, with the goal of providing valuable clinical insights for treating physicians on how patients can embrace a fragrance-free lifestyle.

How Fragrances Act as Allergens

A plethora of chemicals emit odors, of which more than 2000 are used to create the fragranced products we see on our shelves today.¹ For many of these fragrances, contact allergy develops because the fragrance acts as a hapten (ie, a small molecule that combines with a carrier protein to elicit an immune response).² Some fragrance molecules require “activation” to be able to bind to proteins; these are known as prehaptens.³ For example, the natural fragrance linalool is generally considered nonallergenic in its initial form. However, once it is exposed to air, it may undergo oxidation to become linalool hydroperoxides, a well-established contact allergen. Some fragrances can become allergenic in the skin itself, often secondary to enzymatic reactions—these are known as prohaptens.³ However, most fragrances are directly reactive to skin proteins on the basis of chemical reactions such as Michael addition and Schiff base formation.⁴ In either case, the end result is that fragrance allergens, including essential oils, may cause skin sensitization and subsequent ACD.^5,6

Epidemiology

Contact allergy to fragrances is not uncommon; in a multicenter cross-sectional study conducted in 5 European countries, the prevalence in the general population was estimated to be as high as 2.6% and 1.9% among 3119 patients patch tested to fragrance mix I (FMI) and fragrance mix II (FMII), respectively.⁷ Studies in patients referred for patch testing have shown a higher 5% to 25% prevalence of fragrance allergy, largely depending on what population was evaluated.¹ Factors such as sociocultural differences in frequency and types of fragrances used could contribute to this variation.

During patch testing, the primary fragrance screening allergens are FMI, FMII, and balsam of Peru (BOP)(Myroxylon pereirae resin).⁷ In recent years, hydroperoxides of linalool and limonene also have emerged as potentially important fragrance allergens.⁸ The frequencies of patch-test positivity of these allergens can be quite high in referral-based populations. In a study performed by the North American Contact Dermatitis Group (NACDG) from 2019 to 2020, frequencies of fragrance allergen positivity were 12.8% for FMI, 5.2% for FMII, 7.4% for BOP, 11.1% for hydroperoxides of linalool, and 3.5% for hydroperoxides of limonene.⁸ Additionally, it was noted that FMI and hydroperoxides of linalool were among the top 10 most frequently positive allergens.⁹ It should be kept in mind that NACDG studies are drawn from a referral population and not representative of the general population.

Allergic contact dermatitis to fragrances can manifest anywhere on the body, but certain patterns are characteristic. A study by the NACDG analyzed fragrance and botanical patch test results in 24,246 patients and found that fragrance/botanical-sensitive patients more commonly had dermatitis involving the face (odds ratio [OR], 1.12; 95% CI, 1.03-1.21), legs (OR, 1.22; 95% CI, 1.06-1.41), and anal/genital areas (OR, 1.26; 95% CI, 1.04-1.52) and were less likely to have hand dermatitis (OR, 0.88; 95% CI, 0.82-0.95) compared with non–fragrance/botanical-sensitive patients.¹⁰ However, other studies have found that hand dermatitis is common among fragrance-allergic individuals.^11-13

Fragrance allergy tends to be more common in women than men, which likely is attributable to differences in product use and exposure.¹⁰ The prevalence of fragrance allergy increases with age in both men and women, peaking at approximately 50 years of age, likely due to repeat exposure or age-related changes to the skin barrier or immune system.¹⁴

Occupational fragrance exposures are important to consider, and fragrance ACD is associated with hairdressers, beauticians, office workers exposed to aromatherapy diffusers, and food handlers.¹⁵ Less-obvious professions that involve exposure to fragrances used to cover up unwanted odors—such as working with industrial and cleaning chemicals or even metalworking—also have been reported to be associated with ACD.¹⁶

Patch Test Considerations

Patch testing is essential to confirm fragrance allergy and guide treatment, but because there are so many potential fragrance allergens, there is no perfect patch test strategy. In a standard patch test series, the most important screening allergens are considered to be FMI, FMII, and BOP; tested together, they are thought to detect a large proportion of cases of fragrance allergy. Strikingly, in a large European study (N=1951), patch testing with the fragrance markers in the baseline panel failed to detect more than 40% of cases of allergy compared to testing with 26 individual fragrance allergens.¹⁷ Other studies have reported that a smaller proportion of fragrance allergies are missed by using baseline screening allergens alone.^18,19 Limonene and linalool hydroperoxides also are potentially important fragrance allergens to consider adding to the patch test panel, as unoxidized limonene and linalool commonly are used in many products and could theoretically undergo auto-oxidation under use conditions.⁸ However, because of the high number of irritant, questionable, and potentially false-positive reactions, the Information Network of Departments of Dermatology has recommended against adding these hydroperoxides to a standard screening tray for patch testing.²⁰ It must be remembered that a positive patch test to a fragrance does not necessarily represent ACD unless the patient has a clinically relevant exposure to the allergen.²¹

In patients who test negative to the baseline ­fragrance-screening allergens and in whom a high degree of suspicion remains, further testing with supplemental fragrance allergens (commercially available from patch test suppliers) is warranted.¹⁷ The thin-layer rapid use epicutaneous (T.R.U.E.) test (SmartPractice) includes FMI and BOP but not FMII or linalool or limonene hydroperoxides. More comprehensive patch test panels are available that include additional fragrances, such as the North American 80 Comprehensive Series and the American Contact Dermatitis Society Core Allergen Series.^22-24 It is important to remain vigilant and consider expanded patch testing if patients initially test negative but suspicion remains.

Furthermore, patch testing with the patient’s own products is an important consideration. Uter et al²⁵ evaluated patch testing using patients’ perfumes, deodorants, and shaving lotions, and approximately 41% (53/129) of patients who tested positive to their own product tested negative for fragrance-screening allergens. Although it can be difficult to ascertain which exact component of a commercial product is the culprit, a positive patch test may still provide clinically relevant information for patients and treating physicians. In cases of questionable or weak-positive results, repeat testing or repeated open application tests can help re-evaluate suspected products.

Cross-reactivity should be considered when patch testing for fragrances. Atwater et al¹⁰ found that cross-reactivity between FMI, FMII, and BOP was common; for instance, approximately 40% of patients testing positive to FMII or BOP also had positive reactions to FMI (522/1182 and 768/1942, respectively). Understanding this concept is important because in some cases (as detailed below) patients will need to avoid all fragrances, not just the ones to which they have previously been exposed, given the limitations on fragrance labeling in the United States. However, this may change with the Modernization of Cosmetic Regulation Act of 2022.²⁶

Avoiding Fragrances: Improving Patient Education and Outcomes

Once a relevant contact allergy to fragrance is established after patch testing, successful avoidance is critical but challenging, as there are numerous potential pitfalls. Missing just 1 hidden source of fragrance exposure will often be the difference between success or failure. Dermatologists play a crucial role in guiding patients through the intricate process of identifying and avoiding potential allergens.

Optimal Safety: Embracing a Fragrance-Free Lifestyle

For fragrance-allergic patients, it generally is safest to completely avoid fragrance.

First, if a patient only shows positive patch-test reactions to fragrance screening mixes (and not to the particular fragrances in these mixes), there is no way to be certain which fragrances the patient needs to avoid.

Second, even if specific fragrance allergens are identified, numerous chemically related fragrances to which the patient may be allergic are not commercially available for patch testing. One review provided evidence of 162 fragrance allergens that have been documented to cause contact allergy.¹ Dermatologists generally patch test to screening mixtures and/or the 26 fragrance chemicals required on labels in European products (European Directive fragrance).²⁷ Therefore, there are more than 100 known fragrance allergens that are not routinely tested to which patients could be allergic.

Third, certain fragrances, such as limonene and linalool, are found in many products with fragrance, and it is difficult to find products without these substances. Limonene and linalool themselves are not potent allergens; however, upon air exposure, they may auto-oxidize to hydroperoxides of limonene and linalool, which are increasingly common positive patch tests.¹⁹

Additionally, patients should be advised that many products labeled “fragrance free,” “unscented,” or “free and clear” are not truly fragrance free, and patients should not choose products based on these claims. There are no legal definitions for these claims in the United States, and industries are allowed to choose the definition they prefer. Numerous products labeled “unscented” use this term to indicate that the product had an odor, the company used a masking fragrance to hide the odor, and then the product can be considered unscented. In many holistic stores, most products labeled “fragrance free” are only free of artificial fragrances but contain essential oils. Of the 162 documented fragrance allergens, 80 are essential oils.⁶ Essential oils are perceived to be safe by the vast majority of the population because they are viewed as “natural” and “unprocessed” sources of fragrance.²⁸ However, numerous allergenic terpenes have been discovered in essential oils, including functionalized variations of alcohols (eg, geraniol, bisabolol) and aldehydes (eg, citronellal).⁶ Essential oils also consist of nonterpenic compounds produced through the phenylpropanoids pathway, including eugenol and cinnamaldehyde. One review showed that most essential oils contain one or more European Directive fragrance.²⁹ Therefore, many products labeled “unscented,” “fragrance free,” or “natural” are not free of fragrance and may be unsafe for fragrance-allergic patients.

Although not required, manufacturers sometimes voluntarily list one or more of the 162 currently identified fragrance allergens on product labels. Also, there are more than 50 potentially allergenic essential oils that can be listed on labels by their common names or by genus or species. In addition, there are synonyms for fragrance, such as aroma, parfum, perfume, and scent. Therefore, there are several hundred different ingredient names on labels that indicate the presence of fragrance, and patients are very unlikely to successfully identify fragrance-free products by trying to read product labels on their own.

Lastly, in the United States product labels only require products to state that they contain “fragrance” and do not mandate the listing of specific fragrances. If a patient is allergic to a specific fragrance, there is no way to determine if that fragrance is present in these products. This will change with the enactment of Modernization of Cosmetics Regulation Act of 2022, which empowers the US Food and Drug Administration to require manufacturers to disclose many, but not all, fragrance allergens on the labels of cosmetic and topical products.²⁶

For all these reasons, patients should be advised to use a medical database to choose safe alternative products instead of trying to read labels themselves to avoid fragrance. The American Contact Dermatitis Society’s Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) is designed to identify safe alternative products for patients with contact allergies. When CAMP is programmed to avoid “fragrance,” it will list only “safe” products free of all fragrances found in a comprehensive fragrance cross-reactor group.³⁰ This customizable database is available as an application that can be downloaded onto a patient’s mobile device. Fragrance-allergic patients should be encouraged to use the CAMP application or other similar applications (eg, SkinSAFE)(https://www.skinsafeproducts­.com/) to find all the products they use.

Potential Pitfalls in Fragrance Avoidance

Most physicians, even dermatologists, will not know which products on the market are fragrance free from a contact allergy standpoint. Patients should instruct their physicians to use the allergen-avoidance application of choice whenever recommending new topical products, whether prescription or nonprescription. In 2009, Nardelli and colleagues³¹ found that 10% of topical pharmaceutical products contained a total of 66 different fragrance substances.

Individuals who are allergic to fragrance also can react to fragrances used by close contacts (ie, consort dermatitis).³² Therefore, fragrance-allergic individuals who do not improve after changing their personal products should consider urging their spouses or significant others to choose their personal care products using an allergen-avoidance application. Also, physical contact with pets can cause reactions, and the use of a fragrance-free pet shampoo is recommended. Additionally, allergic individuals who are providing care for small children should select fragrance-free products for them.

Some of the most heavily fragranced products on the market are found at hair salons. One exposure to an allergen often can keep patients broken out for up to 4 weeks and occasionally longer, a typical frequency for salon visits—even if the individual is taking great care to avoid fragrance at home. Patients should be instructed to bring their own shampoo, conditioner, and styling products to the salon. These patients also should bring safe moisturizer and nail polish remover for manicures. Additionally, aromatherapy used in most massages can cause flare-ups, and it is recommended that allergic patients purchase fragrance-free massage oil to bring to their sessions.

Fragranced soaps and cleansers can leave a residue on the palmar surface of the hands and fingers. This residue may not meet the threshold for causing a reaction on the thick skin of these surfaces, but it is sufficient to passively transfer fragrance to other more sensitive areas, such as the eyelids. Passive transfer of fragrance can be a major source of allergen exposure and should not be overlooked. Allergic patients should be instructed to bring safe hand cleansers to friends’ houses, restaurants, or work.

Airborne fragrances in a patient’s environment can reach sufficient concentration to cause airborne contact dermatitis. In one case report, an Uber driver developed facial airborne ACD from a fragrance diffuser in his vehicle and his condition improved upon removing the diffuser.³³ Therefore, patients should be instructed to avoid fragranced diffusers, scented candles, room deodorizers, incense, and wax melts.

Fragrance in household products also can be an issue. Fragrance-allergic patients should be instructed to choose fragrance-free cleaning products and to avoid fragranced wipes on surfaces that may be touched. In addition, they should be instructed to use fragrance-free laundry products. It is not required for household products in the United States to list their ingredients, and the majority do not have complete ingredient lists. Therefore, it is imperative that the patient use an allergen-avoidance application that identifies products that have full ingredient disclosure and are free of fragrance.

For individuals who enjoy perfume and/or cologne, it may be possible for them to resume use of these products in some cases after their condition has fully cleared with complete fragrance avoidance. They should avoid spraying products into the air or applying them directly onto the skin and should instead dip a cotton swab into the perfume/cologne and dab a small amount onto their clothing. This technique can sometimes satisfy the patient and improve compliance.

If a patient who is allergic to fragrance does not clear after 6 weeks of complete fragrance avoidance, it is worth considering systemic contact dermatitis due to ingestion of fragrance-related substances in foods.³⁴ A large number of fragrance materials also are food flavorings. For patients allergic to a specific fragrance(s), systemic avoidance needs to be specific to the allergen, and the Flavor and Extract Manufacturers Association’s flavor ingredient library is most helpful (https://www.femaflavor.org/flavor-library). If the patient is allergic to the complex mixture BOP, a balsam-free diet can be attempted.^35,36

Final Thoughts

Dermatologists must equip themselves with the knowledge to educate fragrance-allergic patients on proper avoidance. The multifaceted nature of fragrance avoidance requires a personalized approach, combining label scrutiny, utilization of a safe-product application, and tailored recommendations for specific situations. By guiding patients through these complexities, dermatologists can empower patients to manage their fragrance allergy and enhance their quality of life.

Fragrances are complex organic compounds that are sufficiently volatile to produce an odor—most often a pleasant one—or at times intended to neutralize unpleasant odors. They can be further divided into natural fragrances (eg, essential oils) and synthetic ones. Fragrances are found in abundance in our daily lives: in perfumes; colognes; lotions; shampoos; and an array of other personal, household, and even industrial products (Table). These exposures include products directly applied to the skin, rinsed off, or aerosolized. A single product often contains a multitude of different fragrances to create the scents we know and love. To many, fragrances can be an important part of everyday life or even a part of one’s identity. But that once-intoxicating aroma can transform into an itchy skin nightmare; fragrances are among the most common contact allergens.

Given the widespread prevalence of fragrances in so many products, understanding fragrance allergy and skillful avoidance is imperative. In this review, we explore important aspects of fragrance allergic contact dermatitis (ACD), including chemistry, epidemiology, patch test considerations, and management strategies for patients, with the goal of providing valuable clinical insights for treating physicians on how patients can embrace a fragrance-free lifestyle.

How Fragrances Act as Allergens

A plethora of chemicals emit odors, of which more than 2000 are used to create the fragranced products we see on our shelves today.¹ For many of these fragrances, contact allergy develops because the fragrance acts as a hapten (ie, a small molecule that combines with a carrier protein to elicit an immune response).² Some fragrance molecules require “activation” to be able to bind to proteins; these are known as prehaptens.³ For example, the natural fragrance linalool is generally considered nonallergenic in its initial form. However, once it is exposed to air, it may undergo oxidation to become linalool hydroperoxides, a well-established contact allergen. Some fragrances can become allergenic in the skin itself, often secondary to enzymatic reactions—these are known as prohaptens.³ However, most fragrances are directly reactive to skin proteins on the basis of chemical reactions such as Michael addition and Schiff base formation.⁴ In either case, the end result is that fragrance allergens, including essential oils, may cause skin sensitization and subsequent ACD.^5,6

Epidemiology

Contact allergy to fragrances is not uncommon; in a multicenter cross-sectional study conducted in 5 European countries, the prevalence in the general population was estimated to be as high as 2.6% and 1.9% among 3119 patients patch tested to fragrance mix I (FMI) and fragrance mix II (FMII), respectively.⁷ Studies in patients referred for patch testing have shown a higher 5% to 25% prevalence of fragrance allergy, largely depending on what population was evaluated.¹ Factors such as sociocultural differences in frequency and types of fragrances used could contribute to this variation.

During patch testing, the primary fragrance screening allergens are FMI, FMII, and balsam of Peru (BOP)(Myroxylon pereirae resin).⁷ In recent years, hydroperoxides of linalool and limonene also have emerged as potentially important fragrance allergens.⁸ The frequencies of patch-test positivity of these allergens can be quite high in referral-based populations. In a study performed by the North American Contact Dermatitis Group (NACDG) from 2019 to 2020, frequencies of fragrance allergen positivity were 12.8% for FMI, 5.2% for FMII, 7.4% for BOP, 11.1% for hydroperoxides of linalool, and 3.5% for hydroperoxides of limonene.⁸ Additionally, it was noted that FMI and hydroperoxides of linalool were among the top 10 most frequently positive allergens.⁹ It should be kept in mind that NACDG studies are drawn from a referral population and not representative of the general population.

Allergic contact dermatitis to fragrances can manifest anywhere on the body, but certain patterns are characteristic. A study by the NACDG analyzed fragrance and botanical patch test results in 24,246 patients and found that fragrance/botanical-sensitive patients more commonly had dermatitis involving the face (odds ratio [OR], 1.12; 95% CI, 1.03-1.21), legs (OR, 1.22; 95% CI, 1.06-1.41), and anal/genital areas (OR, 1.26; 95% CI, 1.04-1.52) and were less likely to have hand dermatitis (OR, 0.88; 95% CI, 0.82-0.95) compared with non–fragrance/botanical-sensitive patients.¹⁰ However, other studies have found that hand dermatitis is common among fragrance-allergic individuals.^11-13

Fragrance allergy tends to be more common in women than men, which likely is attributable to differences in product use and exposure.¹⁰ The prevalence of fragrance allergy increases with age in both men and women, peaking at approximately 50 years of age, likely due to repeat exposure or age-related changes to the skin barrier or immune system.¹⁴

Occupational fragrance exposures are important to consider, and fragrance ACD is associated with hairdressers, beauticians, office workers exposed to aromatherapy diffusers, and food handlers.¹⁵ Less-obvious professions that involve exposure to fragrances used to cover up unwanted odors—such as working with industrial and cleaning chemicals or even metalworking—also have been reported to be associated with ACD.¹⁶

Patch Test Considerations

Patch testing is essential to confirm fragrance allergy and guide treatment, but because there are so many potential fragrance allergens, there is no perfect patch test strategy. In a standard patch test series, the most important screening allergens are considered to be FMI, FMII, and BOP; tested together, they are thought to detect a large proportion of cases of fragrance allergy. Strikingly, in a large European study (N=1951), patch testing with the fragrance markers in the baseline panel failed to detect more than 40% of cases of allergy compared to testing with 26 individual fragrance allergens.¹⁷ Other studies have reported that a smaller proportion of fragrance allergies are missed by using baseline screening allergens alone.^18,19 Limonene and linalool hydroperoxides also are potentially important fragrance allergens to consider adding to the patch test panel, as unoxidized limonene and linalool commonly are used in many products and could theoretically undergo auto-oxidation under use conditions.⁸ However, because of the high number of irritant, questionable, and potentially false-positive reactions, the Information Network of Departments of Dermatology has recommended against adding these hydroperoxides to a standard screening tray for patch testing.²⁰ It must be remembered that a positive patch test to a fragrance does not necessarily represent ACD unless the patient has a clinically relevant exposure to the allergen.²¹

In patients who test negative to the baseline ­fragrance-screening allergens and in whom a high degree of suspicion remains, further testing with supplemental fragrance allergens (commercially available from patch test suppliers) is warranted.¹⁷ The thin-layer rapid use epicutaneous (T.R.U.E.) test (SmartPractice) includes FMI and BOP but not FMII or linalool or limonene hydroperoxides. More comprehensive patch test panels are available that include additional fragrances, such as the North American 80 Comprehensive Series and the American Contact Dermatitis Society Core Allergen Series.^22-24 It is important to remain vigilant and consider expanded patch testing if patients initially test negative but suspicion remains.

Furthermore, patch testing with the patient’s own products is an important consideration. Uter et al²⁵ evaluated patch testing using patients’ perfumes, deodorants, and shaving lotions, and approximately 41% (53/129) of patients who tested positive to their own product tested negative for fragrance-screening allergens. Although it can be difficult to ascertain which exact component of a commercial product is the culprit, a positive patch test may still provide clinically relevant information for patients and treating physicians. In cases of questionable or weak-positive results, repeat testing or repeated open application tests can help re-evaluate suspected products.

Cross-reactivity should be considered when patch testing for fragrances. Atwater et al¹⁰ found that cross-reactivity between FMI, FMII, and BOP was common; for instance, approximately 40% of patients testing positive to FMII or BOP also had positive reactions to FMI (522/1182 and 768/1942, respectively). Understanding this concept is important because in some cases (as detailed below) patients will need to avoid all fragrances, not just the ones to which they have previously been exposed, given the limitations on fragrance labeling in the United States. However, this may change with the Modernization of Cosmetic Regulation Act of 2022.²⁶

Avoiding Fragrances: Improving Patient Education and Outcomes

Once a relevant contact allergy to fragrance is established after patch testing, successful avoidance is critical but challenging, as there are numerous potential pitfalls. Missing just 1 hidden source of fragrance exposure will often be the difference between success or failure. Dermatologists play a crucial role in guiding patients through the intricate process of identifying and avoiding potential allergens.

Optimal Safety: Embracing a Fragrance-Free Lifestyle

For fragrance-allergic patients, it generally is safest to completely avoid fragrance.

First, if a patient only shows positive patch-test reactions to fragrance screening mixes (and not to the particular fragrances in these mixes), there is no way to be certain which fragrances the patient needs to avoid.

Second, even if specific fragrance allergens are identified, numerous chemically related fragrances to which the patient may be allergic are not commercially available for patch testing. One review provided evidence of 162 fragrance allergens that have been documented to cause contact allergy.¹ Dermatologists generally patch test to screening mixtures and/or the 26 fragrance chemicals required on labels in European products (European Directive fragrance).²⁷ Therefore, there are more than 100 known fragrance allergens that are not routinely tested to which patients could be allergic.

Third, certain fragrances, such as limonene and linalool, are found in many products with fragrance, and it is difficult to find products without these substances. Limonene and linalool themselves are not potent allergens; however, upon air exposure, they may auto-oxidize to hydroperoxides of limonene and linalool, which are increasingly common positive patch tests.¹⁹

Additionally, patients should be advised that many products labeled “fragrance free,” “unscented,” or “free and clear” are not truly fragrance free, and patients should not choose products based on these claims. There are no legal definitions for these claims in the United States, and industries are allowed to choose the definition they prefer. Numerous products labeled “unscented” use this term to indicate that the product had an odor, the company used a masking fragrance to hide the odor, and then the product can be considered unscented. In many holistic stores, most products labeled “fragrance free” are only free of artificial fragrances but contain essential oils. Of the 162 documented fragrance allergens, 80 are essential oils.⁶ Essential oils are perceived to be safe by the vast majority of the population because they are viewed as “natural” and “unprocessed” sources of fragrance.²⁸ However, numerous allergenic terpenes have been discovered in essential oils, including functionalized variations of alcohols (eg, geraniol, bisabolol) and aldehydes (eg, citronellal).⁶ Essential oils also consist of nonterpenic compounds produced through the phenylpropanoids pathway, including eugenol and cinnamaldehyde. One review showed that most essential oils contain one or more European Directive fragrance.²⁹ Therefore, many products labeled “unscented,” “fragrance free,” or “natural” are not free of fragrance and may be unsafe for fragrance-allergic patients.

Although not required, manufacturers sometimes voluntarily list one or more of the 162 currently identified fragrance allergens on product labels. Also, there are more than 50 potentially allergenic essential oils that can be listed on labels by their common names or by genus or species. In addition, there are synonyms for fragrance, such as aroma, parfum, perfume, and scent. Therefore, there are several hundred different ingredient names on labels that indicate the presence of fragrance, and patients are very unlikely to successfully identify fragrance-free products by trying to read product labels on their own.

Lastly, in the United States product labels only require products to state that they contain “fragrance” and do not mandate the listing of specific fragrances. If a patient is allergic to a specific fragrance, there is no way to determine if that fragrance is present in these products. This will change with the enactment of Modernization of Cosmetics Regulation Act of 2022, which empowers the US Food and Drug Administration to require manufacturers to disclose many, but not all, fragrance allergens on the labels of cosmetic and topical products.²⁶

For all these reasons, patients should be advised to use a medical database to choose safe alternative products instead of trying to read labels themselves to avoid fragrance. The American Contact Dermatitis Society’s Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) is designed to identify safe alternative products for patients with contact allergies. When CAMP is programmed to avoid “fragrance,” it will list only “safe” products free of all fragrances found in a comprehensive fragrance cross-reactor group.³⁰ This customizable database is available as an application that can be downloaded onto a patient’s mobile device. Fragrance-allergic patients should be encouraged to use the CAMP application or other similar applications (eg, SkinSAFE)(https://www.skinsafeproducts­.com/) to find all the products they use.

Potential Pitfalls in Fragrance Avoidance

Most physicians, even dermatologists, will not know which products on the market are fragrance free from a contact allergy standpoint. Patients should instruct their physicians to use the allergen-avoidance application of choice whenever recommending new topical products, whether prescription or nonprescription. In 2009, Nardelli and colleagues³¹ found that 10% of topical pharmaceutical products contained a total of 66 different fragrance substances.

Individuals who are allergic to fragrance also can react to fragrances used by close contacts (ie, consort dermatitis).³² Therefore, fragrance-allergic individuals who do not improve after changing their personal products should consider urging their spouses or significant others to choose their personal care products using an allergen-avoidance application. Also, physical contact with pets can cause reactions, and the use of a fragrance-free pet shampoo is recommended. Additionally, allergic individuals who are providing care for small children should select fragrance-free products for them.

Some of the most heavily fragranced products on the market are found at hair salons. One exposure to an allergen often can keep patients broken out for up to 4 weeks and occasionally longer, a typical frequency for salon visits—even if the individual is taking great care to avoid fragrance at home. Patients should be instructed to bring their own shampoo, conditioner, and styling products to the salon. These patients also should bring safe moisturizer and nail polish remover for manicures. Additionally, aromatherapy used in most massages can cause flare-ups, and it is recommended that allergic patients purchase fragrance-free massage oil to bring to their sessions.

Fragranced soaps and cleansers can leave a residue on the palmar surface of the hands and fingers. This residue may not meet the threshold for causing a reaction on the thick skin of these surfaces, but it is sufficient to passively transfer fragrance to other more sensitive areas, such as the eyelids. Passive transfer of fragrance can be a major source of allergen exposure and should not be overlooked. Allergic patients should be instructed to bring safe hand cleansers to friends’ houses, restaurants, or work.

Airborne fragrances in a patient’s environment can reach sufficient concentration to cause airborne contact dermatitis. In one case report, an Uber driver developed facial airborne ACD from a fragrance diffuser in his vehicle and his condition improved upon removing the diffuser.³³ Therefore, patients should be instructed to avoid fragranced diffusers, scented candles, room deodorizers, incense, and wax melts.

Fragrance in household products also can be an issue. Fragrance-allergic patients should be instructed to choose fragrance-free cleaning products and to avoid fragranced wipes on surfaces that may be touched. In addition, they should be instructed to use fragrance-free laundry products. It is not required for household products in the United States to list their ingredients, and the majority do not have complete ingredient lists. Therefore, it is imperative that the patient use an allergen-avoidance application that identifies products that have full ingredient disclosure and are free of fragrance.

For individuals who enjoy perfume and/or cologne, it may be possible for them to resume use of these products in some cases after their condition has fully cleared with complete fragrance avoidance. They should avoid spraying products into the air or applying them directly onto the skin and should instead dip a cotton swab into the perfume/cologne and dab a small amount onto their clothing. This technique can sometimes satisfy the patient and improve compliance.

If a patient who is allergic to fragrance does not clear after 6 weeks of complete fragrance avoidance, it is worth considering systemic contact dermatitis due to ingestion of fragrance-related substances in foods.³⁴ A large number of fragrance materials also are food flavorings. For patients allergic to a specific fragrance(s), systemic avoidance needs to be specific to the allergen, and the Flavor and Extract Manufacturers Association’s flavor ingredient library is most helpful (https://www.femaflavor.org/flavor-library). If the patient is allergic to the complex mixture BOP, a balsam-free diet can be attempted.^35,36

Final Thoughts

Dermatologists must equip themselves with the knowledge to educate fragrance-allergic patients on proper avoidance. The multifaceted nature of fragrance avoidance requires a personalized approach, combining label scrutiny, utilization of a safe-product application, and tailored recommendations for specific situations. By guiding patients through these complexities, dermatologists can empower patients to manage their fragrance allergy and enhance their quality of life.

Vulvar dermatoses continue to be an overlooked aspect of medical care, highlighting the necessity for enhanced diagnosis and management of these conditions. Here, we address recent advancements in understanding vulvar inflammatory dermatoses other than lichen sclerosus (LS), which was discussed in a prior Guest Editorial¹—specifically vulvovaginal lichen planus (VLP), plasma cell vulvitis (PCV), and vulvar lichen simplex chronicus (LSC).

Vulvar Inflammatory Skin Disease and Quality of Life

There is an increased awareness of the impact vulvar skin disease has on quality of life and its association with anxiety and depression.^2-5 Evaluating the burden of vulvar dermatoses remains an active area of research due to its significance in monitoring disease progression and assessing therapeutic effectiveness. Despite the existence of various dermatology quality-of-life assessment tools, many fail to adequately capture the unique impacts of vulvovaginal diseases, such as sexual or urinary dysfunction. The vulvar quality of life index, which was developed and validated by Saunderson et al⁶ in 2020, consists of a 15-item questionnaire spanning 4 domains: symptoms, anxiety, activities of daily living, and sexuality. This tool has been utilized to gauge treatment response in vulvar conditions and to compare disease burden of various vulvar dermatoses.^7,8 Moving forward, integrating this tool into clinical studies on vulvar skin disease holds promise for enhancing our understanding and management of these conditions.

Vulvovaginal Lichen Planus

Vulvovaginal lichen planus is unique among several prevalent vulvar inflammatory skin disorders encountered by dermatologists—primarily due to its erosive form, which can extend to the vagina, resulting in noninfectious vaginitis and potential vaginal stenosis.^9,10 Managing VLP poses a notable challenge, even when it is confined to the vulva, as it often proves resistant to topical therapies.¹¹

Evaluation for Vaginal Mucosal Disease—In contrast to LS, which typically spares the vaginal mucosa, VLP can involve mucosal sites.^9,12,13 Therefore, it is imperative that all patients with a diagnosis of vulvar VLP undergo evaluation for potential vaginal involvement through speculum examination, wet mount, or vaginal biopsy. Strategies to manage vaginal involvement include use of dilators and pelvic floor physical therapy, lysis of adhesions (if present), topical estrogen, and intravaginal corticosteroids—all tailored to the severity of the disease.^9,11,14

Management of VLP—Approximately 20% to 40% of patients with VLP may require systemic therapy for disease management, including those who are younger, those of non-White ethnicity, and those presenting with vulvar pruritus.¹¹ Various systemic immunosuppressants have been used for VLP, with a recent retrospective study revealing similar response rates for both methotrexate and mycophenolate mofetil in the treatment of VLP.¹⁵ Another retrospective study found hydroxychloroquine to be safe and effective for VLP but noted a slow onset of action, with approximately 70% responding at 9 months following initiation of therapy.¹⁶

Recent attention has shifted to use of targeted therapies for VLP. For instance, apremilast has shown efficacy in a single-center, nonrandomized, open-label pilot study.¹⁷ Tildrakizumab, an IL-23 inhibitor, demonstrated efficacy in a case series involving 24 patients with VLP.¹⁸ Moreover, recent case reports and series have highlighted the potential of oral Janus kinase (JAK) ­inhibitors, such as tofacitinib, in VLP treatment.¹⁹ Clinical trials are ongoing to evaluate the safety and efficacy of topical ruxolitinib and deucravacitinib (a tyrosine kinase 2 inhibitor) in VLP.^20-22 Systemic therapies for VLP currently are used off label, emphasizing the need for future randomized controlled trials to ascertain the optimal therapies for patients affected by erosive and nonerosive forms of this disease.

Plasma Cell Vulvitis

Plasma cell vulvitis is a chronic inflammatory disorder with an unknown etiology that some consider to be a variant of VLP.²³ Others have observed an overlap with desquamative inflammatory vaginitis, categorizing PCV as a hemorrhagic vestibulovaginitis.²⁴ Although its classification as a distinct entity remains under scrutiny, studies indicate a predilection for the nonkeratinized or partially keratinized vulva. A systematic review outlining common clinical findings reported that the most common anatomic sites included the vulvar vestibule, periurethral area, and labia minora.²³ Additionally, reports have emphasized the association between PCV and other inflammatory vulvar skin conditions, including LS.²⁵

Clinical Variants of PCV—A retrospective review proposed 2 clinical phenotypes for PCV: (1) primary non–lichen-associated PCV and (2) secondary lichen-associated PCV, which is linked to LS.²⁶ The primary form is reported to be restricted to the vestibule, and the authors considered this a vulvar counterpart of atrophic vaginitis due to estrogen deficiency (now known as postmenopausal genitourinary syndrome). The secondary phenotype more commonly involved the vestibular and extravestibular epithelium.²⁶

Management of PCV—Recognizing PCV in the context of LS may be important for identifying comorbid conditions and guiding treatment. However, evidence-based guidelines for PCV treatment are lacking. Commonly reported treatment modalities include clobetasol ointment 0.05% and tacrolimus ointment 0.1%.²³ Successful treatment with hydrocortisone suppositories alternating with estradiol vaginal cream was reported in a recent case series.²⁷ Crisaborole also has been reported as a treatment in 1 case of PCV.²⁸ A recent case report found abrocitinib to be effective for the treatment of plasma cell balanitis in the setting of male genital LS,²⁹ but there are limited data on the use of JAK inhibitors for PCV. Further research is necessary to ascertain the incidence, prevalence, clinical subtypes, and optimal management strategies for PCV to effectively treat patients with this condition.

Vulvar LSC

Similar to extragenital LSC, the evaluation of vulvar LSC should prioritize identification of underlying ­etiologies that contribute to the itch-scratch cycle, which may include psoriasis, atopic dermatitis, neurologic conditions, and allergic or irritant contact dermatitis.^30,31 Although treatment strategies may vary based on underlying ­conditions, we will concentrate on updates in managing vulvar LSC and pruritus associated with an atopic ­diathesis or resulting from chronic contact dermatitis, which is prevalent in vulvar skin areas. Finally, we highlight some emerging vulvar allergens for consideration in clinical practice.

Management of Vulvar LSC—The advent of targeted therapies, including biologics and small-molecule inhibitors, for atopic dermatitis and prurigo nodularis in recent years presents potential options for treatment of individuals with vulvar LSC. However, studies on the use of these therapies specifically for vulvar LSC are limited, necessitating thorough discussions with patients. Given the debilitating nature of vulvar pruritus that may be seen in vulvar LSC and the potential inadequacy of topical steroids as monotherapy, systemic therapies may serve as alternative options for patients with refractory disease.³⁰

Dupilumab, a dual inhibitor of IL-4 and IL-13 signaling, has shown rapid and sustained disease improvement in patients with atopic dermatitis, prurigo nodularis, and pruritus.^32,33 Although data on its role in managing vulvar LSC are scarce, a recent case series reported improvement of vulvar pruritus with dupilumab.³⁴ Similarly, tralokinumab, an IL-13 inhibitor approved by the US Food and Drug Administration (FDA) for atopic dermatitis, has shown efficacy in prurigo nodularis³⁵ and may benefit patients with vulvar LSC, though studies on cutaneous outcomes in those with genital involvement specifically are lacking. Oral JAK inhibitors such as upadacitinib and abrocitinib—both FDA approved for atopic dermatitis—have demonstrated efficacy in treating LSC and itch, potentially serving as management options for vulvar LSC in cases resistant to topical steroids or in which steroid atrophy or other steroid adverse effects may preclude continued use of such agents.^36,37 Finally, IL-31 inhibitors such as nemolizumab, which reduced the signs and symptoms of prurigo nodularis in a recent phase 3 clinical trial, may hold utility in addressing vulvar LSC and associated pruritus.³⁸

The topical JAK inhibitor ruxolitinib, which is FDA approved for atopic dermatitis and vitiligo, holds promise for managing LSC on vulvar skin while mitigating the risk for steroid-induced atrophy.³⁹ Additionally, nonsteroidal topicals including roflumilast cream 0.3% and tapinarof cream 1%, both FDA approved for psoriasis, are being evaluated in studies for their safety and efficacy in atopic dermatitis.^40,41 These agents may have the potential to improve signs and symptoms of vulvar LSC, but further studies are necessary.

Vulvar Allergens and LSC—When assessing patients with vulvar LSC, it is crucial to recognize that allergic contact dermatitis is a common primary vulvar dermatosis but can coexist with other vulvar dermatoses such as LS.^13,30 The vulvar skin’s susceptibly to allergic contact dermatitis is attributed to factors such as a higher ratio of antigen-presenting cells in the vulvar skin, the nonkeratinized nature of certain sites, and frequent contact with potential allergens.^42,43 Therefore, incorporating patch testing into the diagnostic process should be considered when evaluating patients with vulvar skin conditions.⁴³

A systemic review identified multiple vulvar allergens, including metals, topical medicaments, fragrances, preservatives, cosmetic constituents, and rubber components that led to contact dermatitis.⁴⁴ Moreover, a recent analysis of topical preparations recommended by women with LS on social media found a high prevalence of known vulvar allergens in these agents, including botanical extracts/spices.⁴⁵ Personal-care wipes marketed for vulvar care and hygiene are known to contain a variety of allergens, with a recent study finding numerous allergens in commercially available wipes including fragrances, scented botanicals in the form of essences, oils, fruit juices, and vitamin E.⁴⁶ These findings underscore the importance of considering potential allergens when caring for patients with vulvar LSC and counseling patients about the potential allergens in many commercially available products that may be recommended on social media sites or by other sources.

Final Thoughts

Vulvar inflammatory dermatoses are becoming increasingly recognized, and there is a need to develop more effective diagnostic and treatment approaches. Recent literature has shed light on some of the challenges in the management of VLP, particularly its resistance to topical therapies and the importance of assessing and managing both cutaneous and vaginal involvement. Efforts have been made to refine the classification of PCV, with studies suggesting a variant that coexists with LS. Although evidence for vulvar-specific treatment of LSC is limited, the emergence of biologics and small-molecule inhibitors that are FDA approved for atopic dermatitis and prurigo nodularis offer promise for certain cases of vulvar LSC and vulvar pruritus. Moreover, recent developments in steroid-sparing topical agents warrant further investigation for their potential efficacy in treating vulvar LSC and possibly other vulvar inflammatory conditions in the future.

Vulvar dermatoses continue to be an overlooked aspect of medical care, highlighting the necessity for enhanced diagnosis and management of these conditions. Here, we address recent advancements in understanding vulvar inflammatory dermatoses other than lichen sclerosus (LS), which was discussed in a prior Guest Editorial¹—specifically vulvovaginal lichen planus (VLP), plasma cell vulvitis (PCV), and vulvar lichen simplex chronicus (LSC).

Vulvar Inflammatory Skin Disease and Quality of Life

There is an increased awareness of the impact vulvar skin disease has on quality of life and its association with anxiety and depression.^2-5 Evaluating the burden of vulvar dermatoses remains an active area of research due to its significance in monitoring disease progression and assessing therapeutic effectiveness. Despite the existence of various dermatology quality-of-life assessment tools, many fail to adequately capture the unique impacts of vulvovaginal diseases, such as sexual or urinary dysfunction. The vulvar quality of life index, which was developed and validated by Saunderson et al⁶ in 2020, consists of a 15-item questionnaire spanning 4 domains: symptoms, anxiety, activities of daily living, and sexuality. This tool has been utilized to gauge treatment response in vulvar conditions and to compare disease burden of various vulvar dermatoses.^7,8 Moving forward, integrating this tool into clinical studies on vulvar skin disease holds promise for enhancing our understanding and management of these conditions.

Vulvovaginal Lichen Planus

Vulvovaginal lichen planus is unique among several prevalent vulvar inflammatory skin disorders encountered by dermatologists—primarily due to its erosive form, which can extend to the vagina, resulting in noninfectious vaginitis and potential vaginal stenosis.^9,10 Managing VLP poses a notable challenge, even when it is confined to the vulva, as it often proves resistant to topical therapies.¹¹

Evaluation for Vaginal Mucosal Disease—In contrast to LS, which typically spares the vaginal mucosa, VLP can involve mucosal sites.^9,12,13 Therefore, it is imperative that all patients with a diagnosis of vulvar VLP undergo evaluation for potential vaginal involvement through speculum examination, wet mount, or vaginal biopsy. Strategies to manage vaginal involvement include use of dilators and pelvic floor physical therapy, lysis of adhesions (if present), topical estrogen, and intravaginal corticosteroids—all tailored to the severity of the disease.^9,11,14

Management of VLP—Approximately 20% to 40% of patients with VLP may require systemic therapy for disease management, including those who are younger, those of non-White ethnicity, and those presenting with vulvar pruritus.¹¹ Various systemic immunosuppressants have been used for VLP, with a recent retrospective study revealing similar response rates for both methotrexate and mycophenolate mofetil in the treatment of VLP.¹⁵ Another retrospective study found hydroxychloroquine to be safe and effective for VLP but noted a slow onset of action, with approximately 70% responding at 9 months following initiation of therapy.¹⁶

Recent attention has shifted to use of targeted therapies for VLP. For instance, apremilast has shown efficacy in a single-center, nonrandomized, open-label pilot study.¹⁷ Tildrakizumab, an IL-23 inhibitor, demonstrated efficacy in a case series involving 24 patients with VLP.¹⁸ Moreover, recent case reports and series have highlighted the potential of oral Janus kinase (JAK) ­inhibitors, such as tofacitinib, in VLP treatment.¹⁹ Clinical trials are ongoing to evaluate the safety and efficacy of topical ruxolitinib and deucravacitinib (a tyrosine kinase 2 inhibitor) in VLP.^20-22 Systemic therapies for VLP currently are used off label, emphasizing the need for future randomized controlled trials to ascertain the optimal therapies for patients affected by erosive and nonerosive forms of this disease.

Plasma Cell Vulvitis

Plasma cell vulvitis is a chronic inflammatory disorder with an unknown etiology that some consider to be a variant of VLP.²³ Others have observed an overlap with desquamative inflammatory vaginitis, categorizing PCV as a hemorrhagic vestibulovaginitis.²⁴ Although its classification as a distinct entity remains under scrutiny, studies indicate a predilection for the nonkeratinized or partially keratinized vulva. A systematic review outlining common clinical findings reported that the most common anatomic sites included the vulvar vestibule, periurethral area, and labia minora.²³ Additionally, reports have emphasized the association between PCV and other inflammatory vulvar skin conditions, including LS.²⁵

Clinical Variants of PCV—A retrospective review proposed 2 clinical phenotypes for PCV: (1) primary non–lichen-associated PCV and (2) secondary lichen-associated PCV, which is linked to LS.²⁶ The primary form is reported to be restricted to the vestibule, and the authors considered this a vulvar counterpart of atrophic vaginitis due to estrogen deficiency (now known as postmenopausal genitourinary syndrome). The secondary phenotype more commonly involved the vestibular and extravestibular epithelium.²⁶

Management of PCV—Recognizing PCV in the context of LS may be important for identifying comorbid conditions and guiding treatment. However, evidence-based guidelines for PCV treatment are lacking. Commonly reported treatment modalities include clobetasol ointment 0.05% and tacrolimus ointment 0.1%.²³ Successful treatment with hydrocortisone suppositories alternating with estradiol vaginal cream was reported in a recent case series.²⁷ Crisaborole also has been reported as a treatment in 1 case of PCV.²⁸ A recent case report found abrocitinib to be effective for the treatment of plasma cell balanitis in the setting of male genital LS,²⁹ but there are limited data on the use of JAK inhibitors for PCV. Further research is necessary to ascertain the incidence, prevalence, clinical subtypes, and optimal management strategies for PCV to effectively treat patients with this condition.

Vulvar LSC

Similar to extragenital LSC, the evaluation of vulvar LSC should prioritize identification of underlying ­etiologies that contribute to the itch-scratch cycle, which may include psoriasis, atopic dermatitis, neurologic conditions, and allergic or irritant contact dermatitis.^30,31 Although treatment strategies may vary based on underlying ­conditions, we will concentrate on updates in managing vulvar LSC and pruritus associated with an atopic ­diathesis or resulting from chronic contact dermatitis, which is prevalent in vulvar skin areas. Finally, we highlight some emerging vulvar allergens for consideration in clinical practice.

Management of Vulvar LSC—The advent of targeted therapies, including biologics and small-molecule inhibitors, for atopic dermatitis and prurigo nodularis in recent years presents potential options for treatment of individuals with vulvar LSC. However, studies on the use of these therapies specifically for vulvar LSC are limited, necessitating thorough discussions with patients. Given the debilitating nature of vulvar pruritus that may be seen in vulvar LSC and the potential inadequacy of topical steroids as monotherapy, systemic therapies may serve as alternative options for patients with refractory disease.³⁰

Dupilumab, a dual inhibitor of IL-4 and IL-13 signaling, has shown rapid and sustained disease improvement in patients with atopic dermatitis, prurigo nodularis, and pruritus.^32,33 Although data on its role in managing vulvar LSC are scarce, a recent case series reported improvement of vulvar pruritus with dupilumab.³⁴ Similarly, tralokinumab, an IL-13 inhibitor approved by the US Food and Drug Administration (FDA) for atopic dermatitis, has shown efficacy in prurigo nodularis³⁵ and may benefit patients with vulvar LSC, though studies on cutaneous outcomes in those with genital involvement specifically are lacking. Oral JAK inhibitors such as upadacitinib and abrocitinib—both FDA approved for atopic dermatitis—have demonstrated efficacy in treating LSC and itch, potentially serving as management options for vulvar LSC in cases resistant to topical steroids or in which steroid atrophy or other steroid adverse effects may preclude continued use of such agents.^36,37 Finally, IL-31 inhibitors such as nemolizumab, which reduced the signs and symptoms of prurigo nodularis in a recent phase 3 clinical trial, may hold utility in addressing vulvar LSC and associated pruritus.³⁸

The topical JAK inhibitor ruxolitinib, which is FDA approved for atopic dermatitis and vitiligo, holds promise for managing LSC on vulvar skin while mitigating the risk for steroid-induced atrophy.³⁹ Additionally, nonsteroidal topicals including roflumilast cream 0.3% and tapinarof cream 1%, both FDA approved for psoriasis, are being evaluated in studies for their safety and efficacy in atopic dermatitis.^40,41 These agents may have the potential to improve signs and symptoms of vulvar LSC, but further studies are necessary.

Vulvar Allergens and LSC—When assessing patients with vulvar LSC, it is crucial to recognize that allergic contact dermatitis is a common primary vulvar dermatosis but can coexist with other vulvar dermatoses such as LS.^13,30 The vulvar skin’s susceptibly to allergic contact dermatitis is attributed to factors such as a higher ratio of antigen-presenting cells in the vulvar skin, the nonkeratinized nature of certain sites, and frequent contact with potential allergens.^42,43 Therefore, incorporating patch testing into the diagnostic process should be considered when evaluating patients with vulvar skin conditions.⁴³

A systemic review identified multiple vulvar allergens, including metals, topical medicaments, fragrances, preservatives, cosmetic constituents, and rubber components that led to contact dermatitis.⁴⁴ Moreover, a recent analysis of topical preparations recommended by women with LS on social media found a high prevalence of known vulvar allergens in these agents, including botanical extracts/spices.⁴⁵ Personal-care wipes marketed for vulvar care and hygiene are known to contain a variety of allergens, with a recent study finding numerous allergens in commercially available wipes including fragrances, scented botanicals in the form of essences, oils, fruit juices, and vitamin E.⁴⁶ These findings underscore the importance of considering potential allergens when caring for patients with vulvar LSC and counseling patients about the potential allergens in many commercially available products that may be recommended on social media sites or by other sources.

Final Thoughts

Vulvar inflammatory dermatoses are becoming increasingly recognized, and there is a need to develop more effective diagnostic and treatment approaches. Recent literature has shed light on some of the challenges in the management of VLP, particularly its resistance to topical therapies and the importance of assessing and managing both cutaneous and vaginal involvement. Efforts have been made to refine the classification of PCV, with studies suggesting a variant that coexists with LS. Although evidence for vulvar-specific treatment of LSC is limited, the emergence of biologics and small-molecule inhibitors that are FDA approved for atopic dermatitis and prurigo nodularis offer promise for certain cases of vulvar LSC and vulvar pruritus. Moreover, recent developments in steroid-sparing topical agents warrant further investigation for their potential efficacy in treating vulvar LSC and possibly other vulvar inflammatory conditions in the future.

Vulvar dermatoses continue to be an overlooked aspect of medical care, highlighting the necessity for enhanced diagnosis and management of these conditions. Here, we address recent advancements in understanding vulvar inflammatory dermatoses other than lichen sclerosus (LS), which was discussed in a prior Guest Editorial¹—specifically vulvovaginal lichen planus (VLP), plasma cell vulvitis (PCV), and vulvar lichen simplex chronicus (LSC).

Vulvar Inflammatory Skin Disease and Quality of Life

There is an increased awareness of the impact vulvar skin disease has on quality of life and its association with anxiety and depression.^2-5 Evaluating the burden of vulvar dermatoses remains an active area of research due to its significance in monitoring disease progression and assessing therapeutic effectiveness. Despite the existence of various dermatology quality-of-life assessment tools, many fail to adequately capture the unique impacts of vulvovaginal diseases, such as sexual or urinary dysfunction. The vulvar quality of life index, which was developed and validated by Saunderson et al⁶ in 2020, consists of a 15-item questionnaire spanning 4 domains: symptoms, anxiety, activities of daily living, and sexuality. This tool has been utilized to gauge treatment response in vulvar conditions and to compare disease burden of various vulvar dermatoses.^7,8 Moving forward, integrating this tool into clinical studies on vulvar skin disease holds promise for enhancing our understanding and management of these conditions.

Vulvovaginal Lichen Planus

Vulvovaginal lichen planus is unique among several prevalent vulvar inflammatory skin disorders encountered by dermatologists—primarily due to its erosive form, which can extend to the vagina, resulting in noninfectious vaginitis and potential vaginal stenosis.^9,10 Managing VLP poses a notable challenge, even when it is confined to the vulva, as it often proves resistant to topical therapies.¹¹

Evaluation for Vaginal Mucosal Disease—In contrast to LS, which typically spares the vaginal mucosa, VLP can involve mucosal sites.^9,12,13 Therefore, it is imperative that all patients with a diagnosis of vulvar VLP undergo evaluation for potential vaginal involvement through speculum examination, wet mount, or vaginal biopsy. Strategies to manage vaginal involvement include use of dilators and pelvic floor physical therapy, lysis of adhesions (if present), topical estrogen, and intravaginal corticosteroids—all tailored to the severity of the disease.^9,11,14

Management of VLP—Approximately 20% to 40% of patients with VLP may require systemic therapy for disease management, including those who are younger, those of non-White ethnicity, and those presenting with vulvar pruritus.¹¹ Various systemic immunosuppressants have been used for VLP, with a recent retrospective study revealing similar response rates for both methotrexate and mycophenolate mofetil in the treatment of VLP.¹⁵ Another retrospective study found hydroxychloroquine to be safe and effective for VLP but noted a slow onset of action, with approximately 70% responding at 9 months following initiation of therapy.¹⁶

Recent attention has shifted to use of targeted therapies for VLP. For instance, apremilast has shown efficacy in a single-center, nonrandomized, open-label pilot study.¹⁷ Tildrakizumab, an IL-23 inhibitor, demonstrated efficacy in a case series involving 24 patients with VLP.¹⁸ Moreover, recent case reports and series have highlighted the potential of oral Janus kinase (JAK) ­inhibitors, such as tofacitinib, in VLP treatment.¹⁹ Clinical trials are ongoing to evaluate the safety and efficacy of topical ruxolitinib and deucravacitinib (a tyrosine kinase 2 inhibitor) in VLP.^20-22 Systemic therapies for VLP currently are used off label, emphasizing the need for future randomized controlled trials to ascertain the optimal therapies for patients affected by erosive and nonerosive forms of this disease.

Plasma Cell Vulvitis

Plasma cell vulvitis is a chronic inflammatory disorder with an unknown etiology that some consider to be a variant of VLP.²³ Others have observed an overlap with desquamative inflammatory vaginitis, categorizing PCV as a hemorrhagic vestibulovaginitis.²⁴ Although its classification as a distinct entity remains under scrutiny, studies indicate a predilection for the nonkeratinized or partially keratinized vulva. A systematic review outlining common clinical findings reported that the most common anatomic sites included the vulvar vestibule, periurethral area, and labia minora.²³ Additionally, reports have emphasized the association between PCV and other inflammatory vulvar skin conditions, including LS.²⁵

Clinical Variants of PCV—A retrospective review proposed 2 clinical phenotypes for PCV: (1) primary non–lichen-associated PCV and (2) secondary lichen-associated PCV, which is linked to LS.²⁶ The primary form is reported to be restricted to the vestibule, and the authors considered this a vulvar counterpart of atrophic vaginitis due to estrogen deficiency (now known as postmenopausal genitourinary syndrome). The secondary phenotype more commonly involved the vestibular and extravestibular epithelium.²⁶

Management of PCV—Recognizing PCV in the context of LS may be important for identifying comorbid conditions and guiding treatment. However, evidence-based guidelines for PCV treatment are lacking. Commonly reported treatment modalities include clobetasol ointment 0.05% and tacrolimus ointment 0.1%.²³ Successful treatment with hydrocortisone suppositories alternating with estradiol vaginal cream was reported in a recent case series.²⁷ Crisaborole also has been reported as a treatment in 1 case of PCV.²⁸ A recent case report found abrocitinib to be effective for the treatment of plasma cell balanitis in the setting of male genital LS,²⁹ but there are limited data on the use of JAK inhibitors for PCV. Further research is necessary to ascertain the incidence, prevalence, clinical subtypes, and optimal management strategies for PCV to effectively treat patients with this condition.

Vulvar LSC

Similar to extragenital LSC, the evaluation of vulvar LSC should prioritize identification of underlying ­etiologies that contribute to the itch-scratch cycle, which may include psoriasis, atopic dermatitis, neurologic conditions, and allergic or irritant contact dermatitis.^30,31 Although treatment strategies may vary based on underlying ­conditions, we will concentrate on updates in managing vulvar LSC and pruritus associated with an atopic ­diathesis or resulting from chronic contact dermatitis, which is prevalent in vulvar skin areas. Finally, we highlight some emerging vulvar allergens for consideration in clinical practice.

Management of Vulvar LSC—The advent of targeted therapies, including biologics and small-molecule inhibitors, for atopic dermatitis and prurigo nodularis in recent years presents potential options for treatment of individuals with vulvar LSC. However, studies on the use of these therapies specifically for vulvar LSC are limited, necessitating thorough discussions with patients. Given the debilitating nature of vulvar pruritus that may be seen in vulvar LSC and the potential inadequacy of topical steroids as monotherapy, systemic therapies may serve as alternative options for patients with refractory disease.³⁰

Dupilumab, a dual inhibitor of IL-4 and IL-13 signaling, has shown rapid and sustained disease improvement in patients with atopic dermatitis, prurigo nodularis, and pruritus.^32,33 Although data on its role in managing vulvar LSC are scarce, a recent case series reported improvement of vulvar pruritus with dupilumab.³⁴ Similarly, tralokinumab, an IL-13 inhibitor approved by the US Food and Drug Administration (FDA) for atopic dermatitis, has shown efficacy in prurigo nodularis³⁵ and may benefit patients with vulvar LSC, though studies on cutaneous outcomes in those with genital involvement specifically are lacking. Oral JAK inhibitors such as upadacitinib and abrocitinib—both FDA approved for atopic dermatitis—have demonstrated efficacy in treating LSC and itch, potentially serving as management options for vulvar LSC in cases resistant to topical steroids or in which steroid atrophy or other steroid adverse effects may preclude continued use of such agents.^36,37 Finally, IL-31 inhibitors such as nemolizumab, which reduced the signs and symptoms of prurigo nodularis in a recent phase 3 clinical trial, may hold utility in addressing vulvar LSC and associated pruritus.³⁸

The topical JAK inhibitor ruxolitinib, which is FDA approved for atopic dermatitis and vitiligo, holds promise for managing LSC on vulvar skin while mitigating the risk for steroid-induced atrophy.³⁹ Additionally, nonsteroidal topicals including roflumilast cream 0.3% and tapinarof cream 1%, both FDA approved for psoriasis, are being evaluated in studies for their safety and efficacy in atopic dermatitis.^40,41 These agents may have the potential to improve signs and symptoms of vulvar LSC, but further studies are necessary.

Vulvar Allergens and LSC—When assessing patients with vulvar LSC, it is crucial to recognize that allergic contact dermatitis is a common primary vulvar dermatosis but can coexist with other vulvar dermatoses such as LS.^13,30 The vulvar skin’s susceptibly to allergic contact dermatitis is attributed to factors such as a higher ratio of antigen-presenting cells in the vulvar skin, the nonkeratinized nature of certain sites, and frequent contact with potential allergens.^42,43 Therefore, incorporating patch testing into the diagnostic process should be considered when evaluating patients with vulvar skin conditions.⁴³

A systemic review identified multiple vulvar allergens, including metals, topical medicaments, fragrances, preservatives, cosmetic constituents, and rubber components that led to contact dermatitis.⁴⁴ Moreover, a recent analysis of topical preparations recommended by women with LS on social media found a high prevalence of known vulvar allergens in these agents, including botanical extracts/spices.⁴⁵ Personal-care wipes marketed for vulvar care and hygiene are known to contain a variety of allergens, with a recent study finding numerous allergens in commercially available wipes including fragrances, scented botanicals in the form of essences, oils, fruit juices, and vitamin E.⁴⁶ These findings underscore the importance of considering potential allergens when caring for patients with vulvar LSC and counseling patients about the potential allergens in many commercially available products that may be recommended on social media sites or by other sources.

Final Thoughts

Vulvar inflammatory dermatoses are becoming increasingly recognized, and there is a need to develop more effective diagnostic and treatment approaches. Recent literature has shed light on some of the challenges in the management of VLP, particularly its resistance to topical therapies and the importance of assessing and managing both cutaneous and vaginal involvement. Efforts have been made to refine the classification of PCV, with studies suggesting a variant that coexists with LS. Although evidence for vulvar-specific treatment of LSC is limited, the emergence of biologics and small-molecule inhibitors that are FDA approved for atopic dermatitis and prurigo nodularis offer promise for certain cases of vulvar LSC and vulvar pruritus. Moreover, recent developments in steroid-sparing topical agents warrant further investigation for their potential efficacy in treating vulvar LSC and possibly other vulvar inflammatory conditions in the future.

Telemedicine interest, which was relatively quiescent prior to the COVID-19 pandemic, has surged in popularity in the past few years.¹ It can now be utilized seamlessly in dermatology practices to deliver exceptional patient care while reducing costs and travel time and offering dermatologists flexibility and improved work-life balance. Teledermatology applications include synchronous, asynchronous, and hybrid platforms.² For synchronous teledermatology, patient visits are carried out in real time with audio and video technology.³ For asynchronous teledermatology—also known as the store-and-forward model—the dermatologist receives the patient’s history and photographs and then renders an assessment and treatment plan.² Hybrid teledermatology uses real-time audio and video conferencing for history taking, assessment and treatment plan, and patient education, with photographs sent asynchronously.³ Telemedicine may not be initially intuitive or easy to integrate into clinical practice, but with time and effort, it will complement your dermatology practice, making it run more efficiently.

Patient Satisfaction With Teledermatology

Studies generally have shown very high patient satisfaction rates and shorter wait times with teledermatology vs in-person visits; for example, in a systematic review of 15 teledermatology studies including 7781 patients, more than 80% of participants reported high satisfaction with their telemedicine visit, with up to 92% reporting that they would choose to do a televisit again.⁴ In a retrospective analysis of 615 Zocdoc physicians, 65% of whom were dermatologists, mean wait times were 2.4 days for virtual appointments compared with 11.7 days for in-person appointments.⁵ Similarly, in a retrospective single-institution study, mean wait times for televisits were 14.3 days compared with 34.7 days for in-person referrals.⁶

Follow-Up Visits for Nail Disorders Via Teledermatology

Teledermatology may be particularly well suited for treating patients with nail disorders. In a prospective observational study, Onyeka et al⁷ accessed 813 images from 63 dermatology patients via teledermatology over a 6-month period to assess distance, focus, brightness, background, and image quality; of them, 83% were rated as high quality. Notably, images of nail disorders, skin growths, or pigmentation disorders were rated as having better image quality than images of inflammatory skin conditions (odds ratio [OR], 4.2-12.9 [P<.005]).⁷ In a retrospective study of 107 telemedicine visits for nail disorders during the COVID-19 pandemic, patients with longitudinal melanonychia were recommended for in-person visits for physical examination and dermoscopy, as were patients with suspected onychomycosis, who required nail plate sampling for diagnostic confirmation; however, approximately half of visits did not require in-person follow-up, including those patients with confirmed onychomycosis.⁸ Onychomycosis patients could be examined for clinical improvement and counseled on medication compliance via telemedicine. Other patients who did not require in-person follow-ups were those with traumatic nail disorders such as subungual hematoma and retronychia as well as those with body‐focused repetitive behaviors, including habit-tic nail deformity, onychophagia, and onychotillomania.⁸

Patients undergoing nail biopsies to rule out malignancies or to diagnose inflammatory nail disorders also may be managed via telemedicine. Patients for whom nail biopsies are recommended often are anxious about the procedure, which may be due to portrayal of nail trauma in the media⁹ or lack of accurate information on nail biopsies online.¹⁰ Therefore, counseling via telemedicine about the details of the procedure in a patient-friendly way (eg, showing an animated video and narrating it¹¹) can allay anxiety without the inconvenience, cost, and time missed from work associated with traveling to an in-person visit. In addition, postoperative counseling ideally is performed via telemedicine because complications following nail procedures are uncommon. In a retrospective study of 502 patients who underwent a nail biopsy at a single academic center, only 14 developed surgical site infections within 8 days on average (range, 5–13 days), with a higher infection risk in patients with type 2 ­diabetes mellitus (P<.0003).¹²

Advantages and Limitations

There are many benefits to incorporating telemedicine into dermatology practices, including reduced overhead costs, convenience and time saved for patients, and flexibility and improved work-life balance for dermatologists. In addition, because the number of in-person visits seen generally is fixed due to space constraints and work-hour restrictions, delegating follow-up visits to telemedicine can free up in-person slots for new patients and those needing procedures. However, there also are some inherent limitations to telemedicine: technology access, vision or hearing difficulties or low digital health literacy, or language barriers. In the prospective observational study by Onyeka et al⁷ analyzing 813 teledermatology images, patients aged 65 to 74 years sent in more clinically useful images (OR, 7.9) and images that were more often in focus (OR, 2.6) compared with patients older than 85 years.

Final Thoughts

Incorporation of telemedicine into dermatologic practice is a valuable tool for triaging patients with acute issues, improving patient care and health care access, making practices more efficient, and improving dermatologist flexibility and work-life balance. Further development of teledermatology to provide access to underserved populations prioritizing dermatologist reimbursement and progress on technologic innovations will make teledermatology even more useful in the coming years.

Telemedicine interest, which was relatively quiescent prior to the COVID-19 pandemic, has surged in popularity in the past few years.¹ It can now be utilized seamlessly in dermatology practices to deliver exceptional patient care while reducing costs and travel time and offering dermatologists flexibility and improved work-life balance. Teledermatology applications include synchronous, asynchronous, and hybrid platforms.² For synchronous teledermatology, patient visits are carried out in real time with audio and video technology.³ For asynchronous teledermatology—also known as the store-and-forward model—the dermatologist receives the patient’s history and photographs and then renders an assessment and treatment plan.² Hybrid teledermatology uses real-time audio and video conferencing for history taking, assessment and treatment plan, and patient education, with photographs sent asynchronously.³ Telemedicine may not be initially intuitive or easy to integrate into clinical practice, but with time and effort, it will complement your dermatology practice, making it run more efficiently.

Patient Satisfaction With Teledermatology

Studies generally have shown very high patient satisfaction rates and shorter wait times with teledermatology vs in-person visits; for example, in a systematic review of 15 teledermatology studies including 7781 patients, more than 80% of participants reported high satisfaction with their telemedicine visit, with up to 92% reporting that they would choose to do a televisit again.⁴ In a retrospective analysis of 615 Zocdoc physicians, 65% of whom were dermatologists, mean wait times were 2.4 days for virtual appointments compared with 11.7 days for in-person appointments.⁵ Similarly, in a retrospective single-institution study, mean wait times for televisits were 14.3 days compared with 34.7 days for in-person referrals.⁶

Follow-Up Visits for Nail Disorders Via Teledermatology

Teledermatology may be particularly well suited for treating patients with nail disorders. In a prospective observational study, Onyeka et al⁷ accessed 813 images from 63 dermatology patients via teledermatology over a 6-month period to assess distance, focus, brightness, background, and image quality; of them, 83% were rated as high quality. Notably, images of nail disorders, skin growths, or pigmentation disorders were rated as having better image quality than images of inflammatory skin conditions (odds ratio [OR], 4.2-12.9 [P<.005]).⁷ In a retrospective study of 107 telemedicine visits for nail disorders during the COVID-19 pandemic, patients with longitudinal melanonychia were recommended for in-person visits for physical examination and dermoscopy, as were patients with suspected onychomycosis, who required nail plate sampling for diagnostic confirmation; however, approximately half of visits did not require in-person follow-up, including those patients with confirmed onychomycosis.⁸ Onychomycosis patients could be examined for clinical improvement and counseled on medication compliance via telemedicine. Other patients who did not require in-person follow-ups were those with traumatic nail disorders such as subungual hematoma and retronychia as well as those with body‐focused repetitive behaviors, including habit-tic nail deformity, onychophagia, and onychotillomania.⁸

Patients undergoing nail biopsies to rule out malignancies or to diagnose inflammatory nail disorders also may be managed via telemedicine. Patients for whom nail biopsies are recommended often are anxious about the procedure, which may be due to portrayal of nail trauma in the media⁹ or lack of accurate information on nail biopsies online.¹⁰ Therefore, counseling via telemedicine about the details of the procedure in a patient-friendly way (eg, showing an animated video and narrating it¹¹) can allay anxiety without the inconvenience, cost, and time missed from work associated with traveling to an in-person visit. In addition, postoperative counseling ideally is performed via telemedicine because complications following nail procedures are uncommon. In a retrospective study of 502 patients who underwent a nail biopsy at a single academic center, only 14 developed surgical site infections within 8 days on average (range, 5–13 days), with a higher infection risk in patients with type 2 ­diabetes mellitus (P<.0003).¹²

Advantages and Limitations

There are many benefits to incorporating telemedicine into dermatology practices, including reduced overhead costs, convenience and time saved for patients, and flexibility and improved work-life balance for dermatologists. In addition, because the number of in-person visits seen generally is fixed due to space constraints and work-hour restrictions, delegating follow-up visits to telemedicine can free up in-person slots for new patients and those needing procedures. However, there also are some inherent limitations to telemedicine: technology access, vision or hearing difficulties or low digital health literacy, or language barriers. In the prospective observational study by Onyeka et al⁷ analyzing 813 teledermatology images, patients aged 65 to 74 years sent in more clinically useful images (OR, 7.9) and images that were more often in focus (OR, 2.6) compared with patients older than 85 years.

Final Thoughts

Incorporation of telemedicine into dermatologic practice is a valuable tool for triaging patients with acute issues, improving patient care and health care access, making practices more efficient, and improving dermatologist flexibility and work-life balance. Further development of teledermatology to provide access to underserved populations prioritizing dermatologist reimbursement and progress on technologic innovations will make teledermatology even more useful in the coming years.

Telemedicine interest, which was relatively quiescent prior to the COVID-19 pandemic, has surged in popularity in the past few years.¹ It can now be utilized seamlessly in dermatology practices to deliver exceptional patient care while reducing costs and travel time and offering dermatologists flexibility and improved work-life balance. Teledermatology applications include synchronous, asynchronous, and hybrid platforms.² For synchronous teledermatology, patient visits are carried out in real time with audio and video technology.³ For asynchronous teledermatology—also known as the store-and-forward model—the dermatologist receives the patient’s history and photographs and then renders an assessment and treatment plan.² Hybrid teledermatology uses real-time audio and video conferencing for history taking, assessment and treatment plan, and patient education, with photographs sent asynchronously.³ Telemedicine may not be initially intuitive or easy to integrate into clinical practice, but with time and effort, it will complement your dermatology practice, making it run more efficiently.

Patient Satisfaction With Teledermatology

Studies generally have shown very high patient satisfaction rates and shorter wait times with teledermatology vs in-person visits; for example, in a systematic review of 15 teledermatology studies including 7781 patients, more than 80% of participants reported high satisfaction with their telemedicine visit, with up to 92% reporting that they would choose to do a televisit again.⁴ In a retrospective analysis of 615 Zocdoc physicians, 65% of whom were dermatologists, mean wait times were 2.4 days for virtual appointments compared with 11.7 days for in-person appointments.⁵ Similarly, in a retrospective single-institution study, mean wait times for televisits were 14.3 days compared with 34.7 days for in-person referrals.⁶

Follow-Up Visits for Nail Disorders Via Teledermatology

Teledermatology may be particularly well suited for treating patients with nail disorders. In a prospective observational study, Onyeka et al⁷ accessed 813 images from 63 dermatology patients via teledermatology over a 6-month period to assess distance, focus, brightness, background, and image quality; of them, 83% were rated as high quality. Notably, images of nail disorders, skin growths, or pigmentation disorders were rated as having better image quality than images of inflammatory skin conditions (odds ratio [OR], 4.2-12.9 [P<.005]).⁷ In a retrospective study of 107 telemedicine visits for nail disorders during the COVID-19 pandemic, patients with longitudinal melanonychia were recommended for in-person visits for physical examination and dermoscopy, as were patients with suspected onychomycosis, who required nail plate sampling for diagnostic confirmation; however, approximately half of visits did not require in-person follow-up, including those patients with confirmed onychomycosis.⁸ Onychomycosis patients could be examined for clinical improvement and counseled on medication compliance via telemedicine. Other patients who did not require in-person follow-ups were those with traumatic nail disorders such as subungual hematoma and retronychia as well as those with body‐focused repetitive behaviors, including habit-tic nail deformity, onychophagia, and onychotillomania.⁸

Patients undergoing nail biopsies to rule out malignancies or to diagnose inflammatory nail disorders also may be managed via telemedicine. Patients for whom nail biopsies are recommended often are anxious about the procedure, which may be due to portrayal of nail trauma in the media⁹ or lack of accurate information on nail biopsies online.¹⁰ Therefore, counseling via telemedicine about the details of the procedure in a patient-friendly way (eg, showing an animated video and narrating it¹¹) can allay anxiety without the inconvenience, cost, and time missed from work associated with traveling to an in-person visit. In addition, postoperative counseling ideally is performed via telemedicine because complications following nail procedures are uncommon. In a retrospective study of 502 patients who underwent a nail biopsy at a single academic center, only 14 developed surgical site infections within 8 days on average (range, 5–13 days), with a higher infection risk in patients with type 2 ­diabetes mellitus (P<.0003).¹²

Advantages and Limitations

There are many benefits to incorporating telemedicine into dermatology practices, including reduced overhead costs, convenience and time saved for patients, and flexibility and improved work-life balance for dermatologists. In addition, because the number of in-person visits seen generally is fixed due to space constraints and work-hour restrictions, delegating follow-up visits to telemedicine can free up in-person slots for new patients and those needing procedures. However, there also are some inherent limitations to telemedicine: technology access, vision or hearing difficulties or low digital health literacy, or language barriers. In the prospective observational study by Onyeka et al⁷ analyzing 813 teledermatology images, patients aged 65 to 74 years sent in more clinically useful images (OR, 7.9) and images that were more often in focus (OR, 2.6) compared with patients older than 85 years.

Final Thoughts

Incorporation of telemedicine into dermatologic practice is a valuable tool for triaging patients with acute issues, improving patient care and health care access, making practices more efficient, and improving dermatologist flexibility and work-life balance. Further development of teledermatology to provide access to underserved populations prioritizing dermatologist reimbursement and progress on technologic innovations will make teledermatology even more useful in the coming years.

Practice Gap

Longitudinal melanonychia (LM) is characterized by the presence of a dark brown, longitudinal, pigmented band on the nail unit, often caused by melanocytic activation or melanocytic hyperplasia in the nail matrix. Distinguishing between benign and early malignant LM is crucial due to their similar clinical presentations.¹ Hence, surgical excision of the pigmented nail matrix followed by histopathologic examination is a common procedure aimed at managing LM and reducing the risk for delayed diagnosis of subungual melanoma.

Tangential matrix excision combined with the nail window technique has emerged as a common and favored surgical strategy for managing LM.² This method is highly valued for its ability to minimize the risk for severe permanent nail dystrophy and effectively reduce postsurgical pigmentation recurrence.

The procedure begins with the creation of a matrix window along the lateral edge of the pigmented band followed by 1 lateral incision carefully made on each side of the nail fold. This meticulous approach allows for the complete exposure of the pigmented lesion. Subsequently, the nail fold is separated from the dorsal surface of the nail plate to facilitate access to the pigmented nail matrix. Finally, the target pigmented area is excised using a scalpel.

Despite the recognized efficacy of this procedure, challenges do arise, particularly when the width of the pigmented matrix lesion is narrow. Holding the scalpel horizontally to ensure precise excision can prove to be demanding, leading to difficulty achieving complete lesion removal and obtaining the desired cosmetic outcomes. As such, there is a clear need to explore alternative tools that can effectively address these challenges while ensuring optimal surgical outcomes for patients with LM. We propose the use of the customized dermal curette.

The Technique

An improved curette tool is a practical solution for complete removal of the pigmented nail matrix. This enhanced instrument is crafted from a sterile disposable dermal curette with its top flattened using a needle holder(Figure 1). Termed the customized dermal curette, this device is a simple yet accurate tool for the precise excision of pigmented lesions within the nail matrix. Importantly, it offers versatility by accommodating different widths of pigmented lesions through the availability of various sizes of dermal curettes (Figure 2).

Histopathologically, we have found that the scalpel technique may lead to variable tissue removal, resulting in differences in tissue thickness, fragility, and completeness (Figure 3A). Conversely, the customized dermal curette consistently provides more accurate tissue excision, resulting in uniform tissue thickness and integrity (Figure 3B).

Practice Implications

Compared to the traditional scalpel, this modified tool offers distinct advantages. Specifically, the customized dermal curette provides enhanced maneuverability and control during the procedure, thereby improving the overall efficacy of the excision process. It also offers a more accurate approach to completely remove pigmented bands, which reduces the risk for postoperative recurrence. The simplicity, affordability, and ease of operation associated with customized dermal curettes holds promise as an effective alternative for tissue shaving, especially in cases involving narrow pigmented matrix lesions, thereby addressing a notable practice gap and enhancing patient care.

Practice Gap

Longitudinal melanonychia (LM) is characterized by the presence of a dark brown, longitudinal, pigmented band on the nail unit, often caused by melanocytic activation or melanocytic hyperplasia in the nail matrix. Distinguishing between benign and early malignant LM is crucial due to their similar clinical presentations.¹ Hence, surgical excision of the pigmented nail matrix followed by histopathologic examination is a common procedure aimed at managing LM and reducing the risk for delayed diagnosis of subungual melanoma.

Tangential matrix excision combined with the nail window technique has emerged as a common and favored surgical strategy for managing LM.² This method is highly valued for its ability to minimize the risk for severe permanent nail dystrophy and effectively reduce postsurgical pigmentation recurrence.

The procedure begins with the creation of a matrix window along the lateral edge of the pigmented band followed by 1 lateral incision carefully made on each side of the nail fold. This meticulous approach allows for the complete exposure of the pigmented lesion. Subsequently, the nail fold is separated from the dorsal surface of the nail plate to facilitate access to the pigmented nail matrix. Finally, the target pigmented area is excised using a scalpel.

Despite the recognized efficacy of this procedure, challenges do arise, particularly when the width of the pigmented matrix lesion is narrow. Holding the scalpel horizontally to ensure precise excision can prove to be demanding, leading to difficulty achieving complete lesion removal and obtaining the desired cosmetic outcomes. As such, there is a clear need to explore alternative tools that can effectively address these challenges while ensuring optimal surgical outcomes for patients with LM. We propose the use of the customized dermal curette.

The Technique

An improved curette tool is a practical solution for complete removal of the pigmented nail matrix. This enhanced instrument is crafted from a sterile disposable dermal curette with its top flattened using a needle holder(Figure 1). Termed the customized dermal curette, this device is a simple yet accurate tool for the precise excision of pigmented lesions within the nail matrix. Importantly, it offers versatility by accommodating different widths of pigmented lesions through the availability of various sizes of dermal curettes (Figure 2).

Histopathologically, we have found that the scalpel technique may lead to variable tissue removal, resulting in differences in tissue thickness, fragility, and completeness (Figure 3A). Conversely, the customized dermal curette consistently provides more accurate tissue excision, resulting in uniform tissue thickness and integrity (Figure 3B).

Practice Implications

Compared to the traditional scalpel, this modified tool offers distinct advantages. Specifically, the customized dermal curette provides enhanced maneuverability and control during the procedure, thereby improving the overall efficacy of the excision process. It also offers a more accurate approach to completely remove pigmented bands, which reduces the risk for postoperative recurrence. The simplicity, affordability, and ease of operation associated with customized dermal curettes holds promise as an effective alternative for tissue shaving, especially in cases involving narrow pigmented matrix lesions, thereby addressing a notable practice gap and enhancing patient care.

Practice Gap

Longitudinal melanonychia (LM) is characterized by the presence of a dark brown, longitudinal, pigmented band on the nail unit, often caused by melanocytic activation or melanocytic hyperplasia in the nail matrix. Distinguishing between benign and early malignant LM is crucial due to their similar clinical presentations.¹ Hence, surgical excision of the pigmented nail matrix followed by histopathologic examination is a common procedure aimed at managing LM and reducing the risk for delayed diagnosis of subungual melanoma.

Tangential matrix excision combined with the nail window technique has emerged as a common and favored surgical strategy for managing LM.² This method is highly valued for its ability to minimize the risk for severe permanent nail dystrophy and effectively reduce postsurgical pigmentation recurrence.

The procedure begins with the creation of a matrix window along the lateral edge of the pigmented band followed by 1 lateral incision carefully made on each side of the nail fold. This meticulous approach allows for the complete exposure of the pigmented lesion. Subsequently, the nail fold is separated from the dorsal surface of the nail plate to facilitate access to the pigmented nail matrix. Finally, the target pigmented area is excised using a scalpel.

Despite the recognized efficacy of this procedure, challenges do arise, particularly when the width of the pigmented matrix lesion is narrow. Holding the scalpel horizontally to ensure precise excision can prove to be demanding, leading to difficulty achieving complete lesion removal and obtaining the desired cosmetic outcomes. As such, there is a clear need to explore alternative tools that can effectively address these challenges while ensuring optimal surgical outcomes for patients with LM. We propose the use of the customized dermal curette.

The Technique

An improved curette tool is a practical solution for complete removal of the pigmented nail matrix. This enhanced instrument is crafted from a sterile disposable dermal curette with its top flattened using a needle holder(Figure 1). Termed the customized dermal curette, this device is a simple yet accurate tool for the precise excision of pigmented lesions within the nail matrix. Importantly, it offers versatility by accommodating different widths of pigmented lesions through the availability of various sizes of dermal curettes (Figure 2).

Histopathologically, we have found that the scalpel technique may lead to variable tissue removal, resulting in differences in tissue thickness, fragility, and completeness (Figure 3A). Conversely, the customized dermal curette consistently provides more accurate tissue excision, resulting in uniform tissue thickness and integrity (Figure 3B).

Practice Implications

Compared to the traditional scalpel, this modified tool offers distinct advantages. Specifically, the customized dermal curette provides enhanced maneuverability and control during the procedure, thereby improving the overall efficacy of the excision process. It also offers a more accurate approach to completely remove pigmented bands, which reduces the risk for postoperative recurrence. The simplicity, affordability, and ease of operation associated with customized dermal curettes holds promise as an effective alternative for tissue shaving, especially in cases involving narrow pigmented matrix lesions, thereby addressing a notable practice gap and enhancing patient care.

The Diagnosis: Microsecretory Adenocarcinoma

Microscopically, the tumor was relatively well circumscribed but had irregular borders. It consisted of microcysts and tubules lined by flattened to plump eosinophilic cells with mildly enlarged nuclei and intraluminal basophilic secretions. Peripheral lymphocytic aggregates also were seen in the mid and deep reticular dermis. Tumor necrosis, lymphovascular invasion, and notable mitotic activity were absent. Immunohistochemistry was diffusely positive for cytokeratin (CK) 7 and CK5/6. Occasional tumor cells showed variable expression of alpha smooth muscle actin, S-100 protein, and p40 and p63 antibodies. Immunohistochemistry was negative for CK20; GATA binding protein 3; MYB proto-oncogene, transcription factor; and insulinoma-associated protein ¹. A dual-color, break-apart fluorescence in situ hybridization probe identified a rearrangement of the SS18 (SYT) gene locus on chromosome 18. The nodule was excised with clear surgical margins, and the patient had no evidence of recurrent disease or metastasis at 2-year follow-up.

In recent years, there has been a growing recognition of the pivotal role played by gene fusions in driving oncogenesis, encompassing a diverse range of benign and malignant cutaneous neoplasms. These investigations have shed light on previously unknown mechanisms and pathways contributing to the pathogenesis of these neoplastic conditions, offering invaluable insights into their underlying biology. As a result, our ability to classify and diagnose these cutaneous tumors has improved. A notable example of how our current understanding has evolved is the discovery of the new cutaneous adnexal tumor microsecretory adenocarcinoma (MSA). Initially described by Bishop et al¹ in 2019 as predominantly occurring in the intraoral minor salivary glands, rare instances of primary cutaneous MSA involving the head and neck regions also have been reported.² Microsecretory adenocarcinoma represents an important addition to the group of fusion-driven tumors with both salivary gland and cutaneous adnexal analogues, characterized by a MEF2C::SS18 gene fusion. This entity is now recognized as a group of cutaneous adnexal tumors with distinct gene fusions, including both relatively recently discovered entities (eg, secretory carcinoma with NTRK fusions) and previously known entities with newly identified gene fusions (eg, poroid neoplasms with NUTM1, YAP1, or WWTR1 fusions; hidradenomatous neoplasms with CRTC1::MAML2 fusions; and adenoid cystic carcinoma with MYB, MYBL1, and/or NFIB rearrangements).³

Microsecretory adenocarcinoma exhibits a high degree of morphologic consistency, characterized by a microcystic-predominant growth pattern, uniform intercalated ductlike tumor cells with attenuated eosinophilic to clear cytoplasm, monotonous oval hyperchromatic nuclei with indistinct nucleoli, abundant basophilic luminal secretions, and a variably cellular fibromyxoid stroma. It also shows rounded borders with subtle infiltrative growth. Occasionally, pseudoepitheliomatous hyperplasia, tumor-associated lymphoid proliferation, or metaplastic bone formation may accompany MSA. Perineural invasion is rare, necrosis is absent, and mitotic rates generally are low, contributing to its distinctive histopathologic features that aid in accurate diagnosis and differentiation from other entities. Immunohistochemistry reveals diffuse positivity for CK7 and patchy to diffuse expression of S-100 in tumor cells as well as variable expression of p40 and p63. Highly specific SS18 gene translocations at chromosome 18q are useful for diagnosing MSA when found alongside its characteristic appearance, and SS18 break-apart fluorescence in situ hybridization can serve reliably as an accurate diagnostic method (Figure 1).⁴ Our case illustrates how molecular analysis assists in distinguishing MSA from other cutaneous adnexal tumors, exemplifying the power of our evolving understanding in refining diagnostic accuracy and guiding targeted therapies in clinical practice.

The differential diagnosis of MSA includes tubular adenoma, secretory carcinoma, cribriform tumor (previously carcinoma), and metastatic adenocarcinoma. Tubular adenoma is a rare benign neoplasm that predominantly affects females and can manifest at any age in adulthood. It typically manifests as a slow-growing, occasionally pedunculated nodule, often measuring less than 2 cm. Although it most commonly manifests on the scalp, tubular adenoma also may arise in diverse sites such as the face, axillae, lower extremities, or genitalia.

Notably, scalp lesions often are associated with nevus sebaceus of Jadassohn or syringocystadenoma papilliferum. Microscopically, tubular adenoma is well circumscribed within the dermis and may extend into the subcutis in some cases. Its distinctive appearance consists of variably sized tubules lined by a double or multilayered cuboidal to columnar epithelium, frequently displaying apocrine decapitation secretion (Figure 2). Cystic changes and intraluminal papillae devoid of true fibrovascular cores frequently are observed. Immunohistochemically, luminal epithelial cells express epithelial membrane antigen and carcinoembryonic antigen, while the myoepithelial layer expresses smooth muscle markers, p40, and S-100 protein. BRAF V600E mutation can be detected using immunohistochemistry, with excellent sensitivity and specificity using the anti-BRAF V600E antibody (clone VE1).⁵ Distinguishing tubular adenoma from MSA is achievable by observing its larger, more variable tubules, along with the consistent presence of a peripheral myoepithelial layer.

Secretory carcinoma is recognized as a low-grade gene fusion–driven carcinoma that primarily arises in salivary glands (both major and minor), with occasional occurrences in the breast and extremely rare instances in other locations such as the skin, thyroid gland, and lung.⁶ Although the axilla is the most common cutaneous site, diverse locations such as the neck, eyelids, extremities, and nipples also have been documented. Secretory carcinoma affects individuals across a wide age range (13–71 years).⁶ The hallmark tumors exhibit densely packed, sievelike microcystic glands and tubular spaces filled with abundant eosinophilic intraluminal secretions (Figure 3). Additionally, morphologic variants, such as predominantly papillary, papillary-cystic, macrocystic, solid, partially mucinous, and mixed-pattern neoplasms, have been described. Secretory carcinoma shares certain features with MSA; however, it is distinguished by the presence of pronounced eosinophilic secretions, plump and vacuolated cytoplasm, and a less conspicuous fibromyxoid stroma. Immunohistochemistry reveals tumor cells that are positive for CK7, SOX-10, S-100, mammaglobin, MUC4, and variably GATA-3. Genetically, secretory carcinoma exhibits distinct characteristics, commonly showing the ETV6::NTRK3 fusion, detectable through molecular techniques or pan-TRK immunohistochemistry, while RET fusions and other rare variants are less frequent.⁷

In 1998, Requena et al⁸ introduced the concept of primary cutaneous cribriform carcinoma. Despite initially being classified as a carcinoma, the malignant potential of this tumor remains uncertain. Consequently, the term cribriform tumor now has become the preferred terminology for denoting this rare entity.⁹ Primary cutaneous cribriform tumors are observed more commonly in women and typically affect individuals aged 20 to 55 years (mean, 44 years). Predominant locations include the upper and lower extremities, especially the thighs, knees, and legs, with additional cases occurring on the head and trunk. Microscopically, cribriform tumor is characterized by a partially circumscribed, unencapsulated dermal nodule composed of round or oval nuclei displaying hyperchromatism and mild pleomorphism. The defining aspect of its morphology revolves around interspersed small round cavities that give rise to the hallmark cribriform pattern (Figure 4). Although MSA occasionally may exhibit a cribriform architectural pattern, it typically lacks the distinctive feature of thin, threadlike, intraluminal bridging strands observed in cribriform tumors. Similarly, luminal cells within the cribriform tumor express CK7 and exhibit variable S-100 expression. It is recognized as an indolent neoplasm with uncertain malignant potential.

The histopathologic features of metastatic carcinomas can overlap with those of primary cutaneous tumors, particularly adnexal neoplasms.¹⁰ However, several key features can aid in the differentiation of cutaneous metastases, including a dermal-based growth pattern with or without subcutaneous involvement, the presence of multiple lesions, and the occurrence of lymphovascular invasion (Figure 5). Conversely, features that suggest a primary cutaneous adnexal neoplasm include the presence of superimposed in situ disease, carcinoma developing within a benign adnexal neoplasm, and notable stromal and/or vascular hyalinization within benign-appearing areas. In some cases, it can be difficult to determine the primary site of origin of a metastatic carcinoma to the skin based on morphologic features alone. In these cases, immunohistochemistry can be helpful. The most cost-effective and time-efficient approach to accurate diagnosis is to obtain a comprehensive clinical history. If there is a known history of cancer, a small panel of organ-specific immunohistochemical studies can be performed to confirm the diagnosis. If there is no known history, an algorithmic approach can be used to identify the primary site of origin. In all circumstances, it cannot be stressed enough that acquiring a thorough clinical history before conducting any diagnostic examinations is paramount.

The Diagnosis: Microsecretory Adenocarcinoma

Microscopically, the tumor was relatively well circumscribed but had irregular borders. It consisted of microcysts and tubules lined by flattened to plump eosinophilic cells with mildly enlarged nuclei and intraluminal basophilic secretions. Peripheral lymphocytic aggregates also were seen in the mid and deep reticular dermis. Tumor necrosis, lymphovascular invasion, and notable mitotic activity were absent. Immunohistochemistry was diffusely positive for cytokeratin (CK) 7 and CK5/6. Occasional tumor cells showed variable expression of alpha smooth muscle actin, S-100 protein, and p40 and p63 antibodies. Immunohistochemistry was negative for CK20; GATA binding protein 3; MYB proto-oncogene, transcription factor; and insulinoma-associated protein ¹. A dual-color, break-apart fluorescence in situ hybridization probe identified a rearrangement of the SS18 (SYT) gene locus on chromosome 18. The nodule was excised with clear surgical margins, and the patient had no evidence of recurrent disease or metastasis at 2-year follow-up.

In recent years, there has been a growing recognition of the pivotal role played by gene fusions in driving oncogenesis, encompassing a diverse range of benign and malignant cutaneous neoplasms. These investigations have shed light on previously unknown mechanisms and pathways contributing to the pathogenesis of these neoplastic conditions, offering invaluable insights into their underlying biology. As a result, our ability to classify and diagnose these cutaneous tumors has improved. A notable example of how our current understanding has evolved is the discovery of the new cutaneous adnexal tumor microsecretory adenocarcinoma (MSA). Initially described by Bishop et al¹ in 2019 as predominantly occurring in the intraoral minor salivary glands, rare instances of primary cutaneous MSA involving the head and neck regions also have been reported.² Microsecretory adenocarcinoma represents an important addition to the group of fusion-driven tumors with both salivary gland and cutaneous adnexal analogues, characterized by a MEF2C::SS18 gene fusion. This entity is now recognized as a group of cutaneous adnexal tumors with distinct gene fusions, including both relatively recently discovered entities (eg, secretory carcinoma with NTRK fusions) and previously known entities with newly identified gene fusions (eg, poroid neoplasms with NUTM1, YAP1, or WWTR1 fusions; hidradenomatous neoplasms with CRTC1::MAML2 fusions; and adenoid cystic carcinoma with MYB, MYBL1, and/or NFIB rearrangements).³

Microsecretory adenocarcinoma exhibits a high degree of morphologic consistency, characterized by a microcystic-predominant growth pattern, uniform intercalated ductlike tumor cells with attenuated eosinophilic to clear cytoplasm, monotonous oval hyperchromatic nuclei with indistinct nucleoli, abundant basophilic luminal secretions, and a variably cellular fibromyxoid stroma. It also shows rounded borders with subtle infiltrative growth. Occasionally, pseudoepitheliomatous hyperplasia, tumor-associated lymphoid proliferation, or metaplastic bone formation may accompany MSA. Perineural invasion is rare, necrosis is absent, and mitotic rates generally are low, contributing to its distinctive histopathologic features that aid in accurate diagnosis and differentiation from other entities. Immunohistochemistry reveals diffuse positivity for CK7 and patchy to diffuse expression of S-100 in tumor cells as well as variable expression of p40 and p63. Highly specific SS18 gene translocations at chromosome 18q are useful for diagnosing MSA when found alongside its characteristic appearance, and SS18 break-apart fluorescence in situ hybridization can serve reliably as an accurate diagnostic method (Figure 1).⁴ Our case illustrates how molecular analysis assists in distinguishing MSA from other cutaneous adnexal tumors, exemplifying the power of our evolving understanding in refining diagnostic accuracy and guiding targeted therapies in clinical practice.

The differential diagnosis of MSA includes tubular adenoma, secretory carcinoma, cribriform tumor (previously carcinoma), and metastatic adenocarcinoma. Tubular adenoma is a rare benign neoplasm that predominantly affects females and can manifest at any age in adulthood. It typically manifests as a slow-growing, occasionally pedunculated nodule, often measuring less than 2 cm. Although it most commonly manifests on the scalp, tubular adenoma also may arise in diverse sites such as the face, axillae, lower extremities, or genitalia.

Notably, scalp lesions often are associated with nevus sebaceus of Jadassohn or syringocystadenoma papilliferum. Microscopically, tubular adenoma is well circumscribed within the dermis and may extend into the subcutis in some cases. Its distinctive appearance consists of variably sized tubules lined by a double or multilayered cuboidal to columnar epithelium, frequently displaying apocrine decapitation secretion (Figure 2). Cystic changes and intraluminal papillae devoid of true fibrovascular cores frequently are observed. Immunohistochemically, luminal epithelial cells express epithelial membrane antigen and carcinoembryonic antigen, while the myoepithelial layer expresses smooth muscle markers, p40, and S-100 protein. BRAF V600E mutation can be detected using immunohistochemistry, with excellent sensitivity and specificity using the anti-BRAF V600E antibody (clone VE1).⁵ Distinguishing tubular adenoma from MSA is achievable by observing its larger, more variable tubules, along with the consistent presence of a peripheral myoepithelial layer.

Secretory carcinoma is recognized as a low-grade gene fusion–driven carcinoma that primarily arises in salivary glands (both major and minor), with occasional occurrences in the breast and extremely rare instances in other locations such as the skin, thyroid gland, and lung.⁶ Although the axilla is the most common cutaneous site, diverse locations such as the neck, eyelids, extremities, and nipples also have been documented. Secretory carcinoma affects individuals across a wide age range (13–71 years).⁶ The hallmark tumors exhibit densely packed, sievelike microcystic glands and tubular spaces filled with abundant eosinophilic intraluminal secretions (Figure 3). Additionally, morphologic variants, such as predominantly papillary, papillary-cystic, macrocystic, solid, partially mucinous, and mixed-pattern neoplasms, have been described. Secretory carcinoma shares certain features with MSA; however, it is distinguished by the presence of pronounced eosinophilic secretions, plump and vacuolated cytoplasm, and a less conspicuous fibromyxoid stroma. Immunohistochemistry reveals tumor cells that are positive for CK7, SOX-10, S-100, mammaglobin, MUC4, and variably GATA-3. Genetically, secretory carcinoma exhibits distinct characteristics, commonly showing the ETV6::NTRK3 fusion, detectable through molecular techniques or pan-TRK immunohistochemistry, while RET fusions and other rare variants are less frequent.⁷

In 1998, Requena et al⁸ introduced the concept of primary cutaneous cribriform carcinoma. Despite initially being classified as a carcinoma, the malignant potential of this tumor remains uncertain. Consequently, the term cribriform tumor now has become the preferred terminology for denoting this rare entity.⁹ Primary cutaneous cribriform tumors are observed more commonly in women and typically affect individuals aged 20 to 55 years (mean, 44 years). Predominant locations include the upper and lower extremities, especially the thighs, knees, and legs, with additional cases occurring on the head and trunk. Microscopically, cribriform tumor is characterized by a partially circumscribed, unencapsulated dermal nodule composed of round or oval nuclei displaying hyperchromatism and mild pleomorphism. The defining aspect of its morphology revolves around interspersed small round cavities that give rise to the hallmark cribriform pattern (Figure 4). Although MSA occasionally may exhibit a cribriform architectural pattern, it typically lacks the distinctive feature of thin, threadlike, intraluminal bridging strands observed in cribriform tumors. Similarly, luminal cells within the cribriform tumor express CK7 and exhibit variable S-100 expression. It is recognized as an indolent neoplasm with uncertain malignant potential.

The histopathologic features of metastatic carcinomas can overlap with those of primary cutaneous tumors, particularly adnexal neoplasms.¹⁰ However, several key features can aid in the differentiation of cutaneous metastases, including a dermal-based growth pattern with or without subcutaneous involvement, the presence of multiple lesions, and the occurrence of lymphovascular invasion (Figure 5). Conversely, features that suggest a primary cutaneous adnexal neoplasm include the presence of superimposed in situ disease, carcinoma developing within a benign adnexal neoplasm, and notable stromal and/or vascular hyalinization within benign-appearing areas. In some cases, it can be difficult to determine the primary site of origin of a metastatic carcinoma to the skin based on morphologic features alone. In these cases, immunohistochemistry can be helpful. The most cost-effective and time-efficient approach to accurate diagnosis is to obtain a comprehensive clinical history. If there is a known history of cancer, a small panel of organ-specific immunohistochemical studies can be performed to confirm the diagnosis. If there is no known history, an algorithmic approach can be used to identify the primary site of origin. In all circumstances, it cannot be stressed enough that acquiring a thorough clinical history before conducting any diagnostic examinations is paramount.

The Diagnosis: Microsecretory Adenocarcinoma

Microscopically, the tumor was relatively well circumscribed but had irregular borders. It consisted of microcysts and tubules lined by flattened to plump eosinophilic cells with mildly enlarged nuclei and intraluminal basophilic secretions. Peripheral lymphocytic aggregates also were seen in the mid and deep reticular dermis. Tumor necrosis, lymphovascular invasion, and notable mitotic activity were absent. Immunohistochemistry was diffusely positive for cytokeratin (CK) 7 and CK5/6. Occasional tumor cells showed variable expression of alpha smooth muscle actin, S-100 protein, and p40 and p63 antibodies. Immunohistochemistry was negative for CK20; GATA binding protein 3; MYB proto-oncogene, transcription factor; and insulinoma-associated protein ¹. A dual-color, break-apart fluorescence in situ hybridization probe identified a rearrangement of the SS18 (SYT) gene locus on chromosome 18. The nodule was excised with clear surgical margins, and the patient had no evidence of recurrent disease or metastasis at 2-year follow-up.

In recent years, there has been a growing recognition of the pivotal role played by gene fusions in driving oncogenesis, encompassing a diverse range of benign and malignant cutaneous neoplasms. These investigations have shed light on previously unknown mechanisms and pathways contributing to the pathogenesis of these neoplastic conditions, offering invaluable insights into their underlying biology. As a result, our ability to classify and diagnose these cutaneous tumors has improved. A notable example of how our current understanding has evolved is the discovery of the new cutaneous adnexal tumor microsecretory adenocarcinoma (MSA). Initially described by Bishop et al¹ in 2019 as predominantly occurring in the intraoral minor salivary glands, rare instances of primary cutaneous MSA involving the head and neck regions also have been reported.² Microsecretory adenocarcinoma represents an important addition to the group of fusion-driven tumors with both salivary gland and cutaneous adnexal analogues, characterized by a MEF2C::SS18 gene fusion. This entity is now recognized as a group of cutaneous adnexal tumors with distinct gene fusions, including both relatively recently discovered entities (eg, secretory carcinoma with NTRK fusions) and previously known entities with newly identified gene fusions (eg, poroid neoplasms with NUTM1, YAP1, or WWTR1 fusions; hidradenomatous neoplasms with CRTC1::MAML2 fusions; and adenoid cystic carcinoma with MYB, MYBL1, and/or NFIB rearrangements).³

Microsecretory adenocarcinoma exhibits a high degree of morphologic consistency, characterized by a microcystic-predominant growth pattern, uniform intercalated ductlike tumor cells with attenuated eosinophilic to clear cytoplasm, monotonous oval hyperchromatic nuclei with indistinct nucleoli, abundant basophilic luminal secretions, and a variably cellular fibromyxoid stroma. It also shows rounded borders with subtle infiltrative growth. Occasionally, pseudoepitheliomatous hyperplasia, tumor-associated lymphoid proliferation, or metaplastic bone formation may accompany MSA. Perineural invasion is rare, necrosis is absent, and mitotic rates generally are low, contributing to its distinctive histopathologic features that aid in accurate diagnosis and differentiation from other entities. Immunohistochemistry reveals diffuse positivity for CK7 and patchy to diffuse expression of S-100 in tumor cells as well as variable expression of p40 and p63. Highly specific SS18 gene translocations at chromosome 18q are useful for diagnosing MSA when found alongside its characteristic appearance, and SS18 break-apart fluorescence in situ hybridization can serve reliably as an accurate diagnostic method (Figure 1).⁴ Our case illustrates how molecular analysis assists in distinguishing MSA from other cutaneous adnexal tumors, exemplifying the power of our evolving understanding in refining diagnostic accuracy and guiding targeted therapies in clinical practice.

The differential diagnosis of MSA includes tubular adenoma, secretory carcinoma, cribriform tumor (previously carcinoma), and metastatic adenocarcinoma. Tubular adenoma is a rare benign neoplasm that predominantly affects females and can manifest at any age in adulthood. It typically manifests as a slow-growing, occasionally pedunculated nodule, often measuring less than 2 cm. Although it most commonly manifests on the scalp, tubular adenoma also may arise in diverse sites such as the face, axillae, lower extremities, or genitalia.

Notably, scalp lesions often are associated with nevus sebaceus of Jadassohn or syringocystadenoma papilliferum. Microscopically, tubular adenoma is well circumscribed within the dermis and may extend into the subcutis in some cases. Its distinctive appearance consists of variably sized tubules lined by a double or multilayered cuboidal to columnar epithelium, frequently displaying apocrine decapitation secretion (Figure 2). Cystic changes and intraluminal papillae devoid of true fibrovascular cores frequently are observed. Immunohistochemically, luminal epithelial cells express epithelial membrane antigen and carcinoembryonic antigen, while the myoepithelial layer expresses smooth muscle markers, p40, and S-100 protein. BRAF V600E mutation can be detected using immunohistochemistry, with excellent sensitivity and specificity using the anti-BRAF V600E antibody (clone VE1).⁵ Distinguishing tubular adenoma from MSA is achievable by observing its larger, more variable tubules, along with the consistent presence of a peripheral myoepithelial layer.

Secretory carcinoma is recognized as a low-grade gene fusion–driven carcinoma that primarily arises in salivary glands (both major and minor), with occasional occurrences in the breast and extremely rare instances in other locations such as the skin, thyroid gland, and lung.⁶ Although the axilla is the most common cutaneous site, diverse locations such as the neck, eyelids, extremities, and nipples also have been documented. Secretory carcinoma affects individuals across a wide age range (13–71 years).⁶ The hallmark tumors exhibit densely packed, sievelike microcystic glands and tubular spaces filled with abundant eosinophilic intraluminal secretions (Figure 3). Additionally, morphologic variants, such as predominantly papillary, papillary-cystic, macrocystic, solid, partially mucinous, and mixed-pattern neoplasms, have been described. Secretory carcinoma shares certain features with MSA; however, it is distinguished by the presence of pronounced eosinophilic secretions, plump and vacuolated cytoplasm, and a less conspicuous fibromyxoid stroma. Immunohistochemistry reveals tumor cells that are positive for CK7, SOX-10, S-100, mammaglobin, MUC4, and variably GATA-3. Genetically, secretory carcinoma exhibits distinct characteristics, commonly showing the ETV6::NTRK3 fusion, detectable through molecular techniques or pan-TRK immunohistochemistry, while RET fusions and other rare variants are less frequent.⁷

In 1998, Requena et al⁸ introduced the concept of primary cutaneous cribriform carcinoma. Despite initially being classified as a carcinoma, the malignant potential of this tumor remains uncertain. Consequently, the term cribriform tumor now has become the preferred terminology for denoting this rare entity.⁹ Primary cutaneous cribriform tumors are observed more commonly in women and typically affect individuals aged 20 to 55 years (mean, 44 years). Predominant locations include the upper and lower extremities, especially the thighs, knees, and legs, with additional cases occurring on the head and trunk. Microscopically, cribriform tumor is characterized by a partially circumscribed, unencapsulated dermal nodule composed of round or oval nuclei displaying hyperchromatism and mild pleomorphism. The defining aspect of its morphology revolves around interspersed small round cavities that give rise to the hallmark cribriform pattern (Figure 4). Although MSA occasionally may exhibit a cribriform architectural pattern, it typically lacks the distinctive feature of thin, threadlike, intraluminal bridging strands observed in cribriform tumors. Similarly, luminal cells within the cribriform tumor express CK7 and exhibit variable S-100 expression. It is recognized as an indolent neoplasm with uncertain malignant potential.

The histopathologic features of metastatic carcinomas can overlap with those of primary cutaneous tumors, particularly adnexal neoplasms.¹⁰ However, several key features can aid in the differentiation of cutaneous metastases, including a dermal-based growth pattern with or without subcutaneous involvement, the presence of multiple lesions, and the occurrence of lymphovascular invasion (Figure 5). Conversely, features that suggest a primary cutaneous adnexal neoplasm include the presence of superimposed in situ disease, carcinoma developing within a benign adnexal neoplasm, and notable stromal and/or vascular hyalinization within benign-appearing areas. In some cases, it can be difficult to determine the primary site of origin of a metastatic carcinoma to the skin based on morphologic features alone. In these cases, immunohistochemistry can be helpful. The most cost-effective and time-efficient approach to accurate diagnosis is to obtain a comprehensive clinical history. If there is a known history of cancer, a small panel of organ-specific immunohistochemical studies can be performed to confirm the diagnosis. If there is no known history, an algorithmic approach can be used to identify the primary site of origin. In all circumstances, it cannot be stressed enough that acquiring a thorough clinical history before conducting any diagnostic examinations is paramount.

Skin grafting is a surgical technique used to cover skin defects resulting from the removal of skin tumors, ulcers, or burn injuries.^1-3 Complications can occur at both donor and recipient sites and may include bleeding, hematoma/seroma formation, postoperative pain, infection, scarring, paresthesia, skin pigmentation, graft contracture, and graft failure.^1,2,4,5 The development of epidermal tumors is not commonly reported among the complications of skin grafting; however, cases of epidermal tumor development on skin graft donor sites during the postoperative period have been reported.^6-12

We performed a systematic review of the literature for cases of epidermal tumor development on skin graft donor sites in patients undergoing autologous skin graft surgery. We present the clinical characteristics of these cases and discuss the nature of these tumors.

Methods

Search Strategy and Study Selection—A literature search was conducted by 2 independent researchers (Z.P. and V.P.) for articles published before December 2022 in the following databases: MEDLINE/PubMed, Web of Science, Scopus, Cochrane Library, OpenGrey, Google Scholar, and WorldCat. Search terms included all possible combinations of the following: keratoacanthoma, molluscum sebaceum, basal cell carcinoma, squamous cell carcinoma, acanthoma, wart, Merkel cell carcinoma, verruca, Bowen disease, keratosis, skin cancer, cutaneous cancer, skin neoplasia, cutaneous neoplasia, and skin tumor. The literature search terms were selected based on the World Health Organization classification of skin tumors.¹³ Manual bibliography checks were performed on all eligible search results for possible relevant studies. Discrepancies were resolved through discussion and, if needed, mediation by a third researcher (N.C.). To be included, a study had to report a case(s) of epidermal tumor(s) that was confirmed by histopathology and arose on a graft donor site in a patient receiving autologous skin grafts for any reason. No language, geographic, or report date restrictions were set.

Data Extraction, Quality Assessment, and Statistical Analysis—We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.¹⁴ Two independent researchers (Z.P. and V.P.) retrieved the data from the included studies. We have used the terms case and patient interchangeably, and 1 month was measured as 4 weeks for simplicity. Disagreements were resolved by discussion and mediation by a third researcher (N.C.). The quality of the included studies was assessed by 2 researchers (M.P. and V.P.) using the tool proposed by Murad et al.¹⁵

We used descriptive statistical analysis to analyze clinical characteristics of the included cases. We performed separate descriptive analyses based on the most frequently reported types of epidermal tumors and compared the differences between different groups using the Mann-Whitney U test, χ2 test, and Fisher exact test. The level of significance was set at P<.05. All statistical analyses were conducted using SPSS (version 29).

Results

Literature Search and Characteristics of Included Studies—The initial literature search identified 1378 studies, which were screened based on title and abstract. After removing duplicate and irrelevant studies and evaluating the full text of eligible studies, 31 studies (4 case series and 27 case reports) were included in the systematic review (Figure).^6-12,16-39 Quality assessment of the included studies is presented in Table 1.

Clinical Characteristics of Included Patients—Our systematic review included 36 patients with a mean age of 63 years and a male to female ratio of 2:1. The 2 most common causes for skin grafting were burn wounds and surgical excision of skin tumors. Most grafts were harvested from the thighs. The development of a solitary lesion on the donor area was reported in two-thirds of the patients, while more than 1 lesion developed in the remaining one-third of patients. The median time to tumor development was 6.5 weeks. In most cases, a split-thickness skin graft was used.

Cutaneous squamous cell carcinomas (CSCCs) were found in 23 patients, with well-differentiated CSCCs in 19 of these cases. Additionally, keratoacanthomas (KAs) were found in 10 patients. The majority of patients underwent surgical excision of the tumor. The median follow-up time was 12 months, during which recurrences were noted in a small percentage of cases. Clinical characteristics of included patients are presented in Table 2.

Comment

Reasons for Tumor Development on Skin Graft Donor Sites—The etiology behind epidermal tumor development on graft donor sites is unclear. According to one theory, iatrogenic contamination of the donor site during the removal of a primary epidermal tumor could be responsible. However, contemporary surgical procedures dictate the use of different sets of instruments for separate surgical sites. Moreover, this theory cannot explain the occurrence of epidermal tumors on donor sites in patients who have undergone skin grafting for the repair of burn wounds.³⁷

Another theory suggests that hematogenous and/or lymphatic spread can occur from the site of the primary epidermal tumor to the donor site, which has increased vascularization.^16,37 However, this theory also fails to provide an explanation for the development of epidermal tumors in patients who receive skin grafts for burn wounds.

A third theory states that the microenvironment of the donor site is key to tumor development. The donor site undergoes acute inflammation due to the trauma from harvesting the skin graft. According to this theory, acute inflammation could promote neoplastic growth and thus explain the development of epidermal tumors on the donor site.^8,26 However, the relationship between acute inflammation and carcinogenesis remains unclear. What is known to date is that the development of CSCC has been documented primarily in chronically inflamed tissues, whereas the development of KA—a variant of CSCC with distinctive and more benign clinical characteristics—can be expected in the setting of acute trauma-related inflammation.^13,40,41

Based on our systematic review, we propose that well-differentiated CSCC on graft donor sites might actually be misdiagnosed KA, given that the histopathologic differential diagnosis between CSCC and KA is extremely challenging.⁴² This hypothesis could explain the development of well-differentiated CSCC and KA on graft donor sites.

Conclusion

Development of CSCC and KA on graft donor sites can be listed among the postoperative complications of autologous skin grafting. Patients and physicians should be aware of this potential complication, and donor sites should be monitored for the occurrence of epidermal tumors.

Skin grafting is a surgical technique used to cover skin defects resulting from the removal of skin tumors, ulcers, or burn injuries.^1-3 Complications can occur at both donor and recipient sites and may include bleeding, hematoma/seroma formation, postoperative pain, infection, scarring, paresthesia, skin pigmentation, graft contracture, and graft failure.^1,2,4,5 The development of epidermal tumors is not commonly reported among the complications of skin grafting; however, cases of epidermal tumor development on skin graft donor sites during the postoperative period have been reported.^6-12

We performed a systematic review of the literature for cases of epidermal tumor development on skin graft donor sites in patients undergoing autologous skin graft surgery. We present the clinical characteristics of these cases and discuss the nature of these tumors.

Methods

Search Strategy and Study Selection—A literature search was conducted by 2 independent researchers (Z.P. and V.P.) for articles published before December 2022 in the following databases: MEDLINE/PubMed, Web of Science, Scopus, Cochrane Library, OpenGrey, Google Scholar, and WorldCat. Search terms included all possible combinations of the following: keratoacanthoma, molluscum sebaceum, basal cell carcinoma, squamous cell carcinoma, acanthoma, wart, Merkel cell carcinoma, verruca, Bowen disease, keratosis, skin cancer, cutaneous cancer, skin neoplasia, cutaneous neoplasia, and skin tumor. The literature search terms were selected based on the World Health Organization classification of skin tumors.¹³ Manual bibliography checks were performed on all eligible search results for possible relevant studies. Discrepancies were resolved through discussion and, if needed, mediation by a third researcher (N.C.). To be included, a study had to report a case(s) of epidermal tumor(s) that was confirmed by histopathology and arose on a graft donor site in a patient receiving autologous skin grafts for any reason. No language, geographic, or report date restrictions were set.

Data Extraction, Quality Assessment, and Statistical Analysis—We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.¹⁴ Two independent researchers (Z.P. and V.P.) retrieved the data from the included studies. We have used the terms case and patient interchangeably, and 1 month was measured as 4 weeks for simplicity. Disagreements were resolved by discussion and mediation by a third researcher (N.C.). The quality of the included studies was assessed by 2 researchers (M.P. and V.P.) using the tool proposed by Murad et al.¹⁵

We used descriptive statistical analysis to analyze clinical characteristics of the included cases. We performed separate descriptive analyses based on the most frequently reported types of epidermal tumors and compared the differences between different groups using the Mann-Whitney U test, χ2 test, and Fisher exact test. The level of significance was set at P<.05. All statistical analyses were conducted using SPSS (version 29).

Results

Literature Search and Characteristics of Included Studies—The initial literature search identified 1378 studies, which were screened based on title and abstract. After removing duplicate and irrelevant studies and evaluating the full text of eligible studies, 31 studies (4 case series and 27 case reports) were included in the systematic review (Figure).^6-12,16-39 Quality assessment of the included studies is presented in Table 1.

Clinical Characteristics of Included Patients—Our systematic review included 36 patients with a mean age of 63 years and a male to female ratio of 2:1. The 2 most common causes for skin grafting were burn wounds and surgical excision of skin tumors. Most grafts were harvested from the thighs. The development of a solitary lesion on the donor area was reported in two-thirds of the patients, while more than 1 lesion developed in the remaining one-third of patients. The median time to tumor development was 6.5 weeks. In most cases, a split-thickness skin graft was used.

Cutaneous squamous cell carcinomas (CSCCs) were found in 23 patients, with well-differentiated CSCCs in 19 of these cases. Additionally, keratoacanthomas (KAs) were found in 10 patients. The majority of patients underwent surgical excision of the tumor. The median follow-up time was 12 months, during which recurrences were noted in a small percentage of cases. Clinical characteristics of included patients are presented in Table 2.

Comment

Reasons for Tumor Development on Skin Graft Donor Sites—The etiology behind epidermal tumor development on graft donor sites is unclear. According to one theory, iatrogenic contamination of the donor site during the removal of a primary epidermal tumor could be responsible. However, contemporary surgical procedures dictate the use of different sets of instruments for separate surgical sites. Moreover, this theory cannot explain the occurrence of epidermal tumors on donor sites in patients who have undergone skin grafting for the repair of burn wounds.³⁷

Another theory suggests that hematogenous and/or lymphatic spread can occur from the site of the primary epidermal tumor to the donor site, which has increased vascularization.^16,37 However, this theory also fails to provide an explanation for the development of epidermal tumors in patients who receive skin grafts for burn wounds.

A third theory states that the microenvironment of the donor site is key to tumor development. The donor site undergoes acute inflammation due to the trauma from harvesting the skin graft. According to this theory, acute inflammation could promote neoplastic growth and thus explain the development of epidermal tumors on the donor site.^8,26 However, the relationship between acute inflammation and carcinogenesis remains unclear. What is known to date is that the development of CSCC has been documented primarily in chronically inflamed tissues, whereas the development of KA—a variant of CSCC with distinctive and more benign clinical characteristics—can be expected in the setting of acute trauma-related inflammation.^13,40,41

Based on our systematic review, we propose that well-differentiated CSCC on graft donor sites might actually be misdiagnosed KA, given that the histopathologic differential diagnosis between CSCC and KA is extremely challenging.⁴² This hypothesis could explain the development of well-differentiated CSCC and KA on graft donor sites.

Conclusion

Development of CSCC and KA on graft donor sites can be listed among the postoperative complications of autologous skin grafting. Patients and physicians should be aware of this potential complication, and donor sites should be monitored for the occurrence of epidermal tumors.

Skin grafting is a surgical technique used to cover skin defects resulting from the removal of skin tumors, ulcers, or burn injuries.^1-3 Complications can occur at both donor and recipient sites and may include bleeding, hematoma/seroma formation, postoperative pain, infection, scarring, paresthesia, skin pigmentation, graft contracture, and graft failure.^1,2,4,5 The development of epidermal tumors is not commonly reported among the complications of skin grafting; however, cases of epidermal tumor development on skin graft donor sites during the postoperative period have been reported.^6-12

We performed a systematic review of the literature for cases of epidermal tumor development on skin graft donor sites in patients undergoing autologous skin graft surgery. We present the clinical characteristics of these cases and discuss the nature of these tumors.

Methods

Search Strategy and Study Selection—A literature search was conducted by 2 independent researchers (Z.P. and V.P.) for articles published before December 2022 in the following databases: MEDLINE/PubMed, Web of Science, Scopus, Cochrane Library, OpenGrey, Google Scholar, and WorldCat. Search terms included all possible combinations of the following: keratoacanthoma, molluscum sebaceum, basal cell carcinoma, squamous cell carcinoma, acanthoma, wart, Merkel cell carcinoma, verruca, Bowen disease, keratosis, skin cancer, cutaneous cancer, skin neoplasia, cutaneous neoplasia, and skin tumor. The literature search terms were selected based on the World Health Organization classification of skin tumors.¹³ Manual bibliography checks were performed on all eligible search results for possible relevant studies. Discrepancies were resolved through discussion and, if needed, mediation by a third researcher (N.C.). To be included, a study had to report a case(s) of epidermal tumor(s) that was confirmed by histopathology and arose on a graft donor site in a patient receiving autologous skin grafts for any reason. No language, geographic, or report date restrictions were set.

Data Extraction, Quality Assessment, and Statistical Analysis—We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.¹⁴ Two independent researchers (Z.P. and V.P.) retrieved the data from the included studies. We have used the terms case and patient interchangeably, and 1 month was measured as 4 weeks for simplicity. Disagreements were resolved by discussion and mediation by a third researcher (N.C.). The quality of the included studies was assessed by 2 researchers (M.P. and V.P.) using the tool proposed by Murad et al.¹⁵

We used descriptive statistical analysis to analyze clinical characteristics of the included cases. We performed separate descriptive analyses based on the most frequently reported types of epidermal tumors and compared the differences between different groups using the Mann-Whitney U test, χ2 test, and Fisher exact test. The level of significance was set at P<.05. All statistical analyses were conducted using SPSS (version 29).

Results

Literature Search and Characteristics of Included Studies—The initial literature search identified 1378 studies, which were screened based on title and abstract. After removing duplicate and irrelevant studies and evaluating the full text of eligible studies, 31 studies (4 case series and 27 case reports) were included in the systematic review (Figure).^6-12,16-39 Quality assessment of the included studies is presented in Table 1.

Clinical Characteristics of Included Patients—Our systematic review included 36 patients with a mean age of 63 years and a male to female ratio of 2:1. The 2 most common causes for skin grafting were burn wounds and surgical excision of skin tumors. Most grafts were harvested from the thighs. The development of a solitary lesion on the donor area was reported in two-thirds of the patients, while more than 1 lesion developed in the remaining one-third of patients. The median time to tumor development was 6.5 weeks. In most cases, a split-thickness skin graft was used.

Cutaneous squamous cell carcinomas (CSCCs) were found in 23 patients, with well-differentiated CSCCs in 19 of these cases. Additionally, keratoacanthomas (KAs) were found in 10 patients. The majority of patients underwent surgical excision of the tumor. The median follow-up time was 12 months, during which recurrences were noted in a small percentage of cases. Clinical characteristics of included patients are presented in Table 2.

Comment

Reasons for Tumor Development on Skin Graft Donor Sites—The etiology behind epidermal tumor development on graft donor sites is unclear. According to one theory, iatrogenic contamination of the donor site during the removal of a primary epidermal tumor could be responsible. However, contemporary surgical procedures dictate the use of different sets of instruments for separate surgical sites. Moreover, this theory cannot explain the occurrence of epidermal tumors on donor sites in patients who have undergone skin grafting for the repair of burn wounds.³⁷

Another theory suggests that hematogenous and/or lymphatic spread can occur from the site of the primary epidermal tumor to the donor site, which has increased vascularization.^16,37 However, this theory also fails to provide an explanation for the development of epidermal tumors in patients who receive skin grafts for burn wounds.

A third theory states that the microenvironment of the donor site is key to tumor development. The donor site undergoes acute inflammation due to the trauma from harvesting the skin graft. According to this theory, acute inflammation could promote neoplastic growth and thus explain the development of epidermal tumors on the donor site.^8,26 However, the relationship between acute inflammation and carcinogenesis remains unclear. What is known to date is that the development of CSCC has been documented primarily in chronically inflamed tissues, whereas the development of KA—a variant of CSCC with distinctive and more benign clinical characteristics—can be expected in the setting of acute trauma-related inflammation.^13,40,41

Based on our systematic review, we propose that well-differentiated CSCC on graft donor sites might actually be misdiagnosed KA, given that the histopathologic differential diagnosis between CSCC and KA is extremely challenging.⁴² This hypothesis could explain the development of well-differentiated CSCC and KA on graft donor sites.

Conclusion

Development of CSCC and KA on graft donor sites can be listed among the postoperative complications of autologous skin grafting. Patients and physicians should be aware of this potential complication, and donor sites should be monitored for the occurrence of epidermal tumors.

To the Editor:

Syringoma is a relatively common benign adnexal neoplasm originating in the ducts of eccrine sweat glands. It can be divided into 4 variants based on clinical features: localized; familial; Down syndrome associated; and generalized, which includes multiple syringomas and eruptive syringoma (ES).¹ Eruptive syringoma is a rare variant of generalized syringoma that was first described by Jacquet and Darier² in 1887. Clinically, ES lesions manifest as multiple nonfused, flesh-colored to reddish-brown papules that are located most commonly on the anterior trunk during childhood or adolescence. Eruptive syringoma can be missed easily or misdiagnosed clinically. We present 3 rare cases of ES.

A 28-year-old man presented with multiple asymptomatic papules on the trunk and upper arms of 20 years’ duration (patient 1). He had been diagnosed with Darier disease 3 years prior to the current presentation and was treated with oral and topical retinoic acid without a response. After 3 months of oral treatment, the retinoic acid was stopped due to elevated liver enzymes. Physical examination at the current presentation revealed multiple smooth, firm, nonfused, 1- to 4-mm, reddish to dark red papules on the neck, chest, abdomen, and flexural surfaces of the upper arms (Figure 1A). Dermoscopy of the arm lesions showed light brown pigment networks and yellowish-white unstructured areas surrounded by linear vessels on a pink background under polarized light (Figure 1B). Histopathologic examination of a lesion on the left arm revealed epithelial cords, ducts, and cystic structures within the superficial and mid dermis. The ducts were lined by 2 rows of epithelial cells with a characteristic tadpolelike pattern and filled with eosinophilic amorphous substances (Figure 1C).

A 43-year-old man who was otherwise healthy presented with brownish flat-topped papules on the chest and abdomen of 19 years’ duration (Figure 3A)(patient 3). The lesions had remained stable and did not progress. He denied any treatment. Dermoscopy of the chest lesions showed a light brown pigment network as well as dotted and linear vessels on a pale yellow background (Figure 3B).

All 3 patients demonstrated classic histopathologic features of syringoma, and none had a family history of similar skin lesions. The clinical and dermoscopic findings along with the histopathology in all 3 patients were consistent with ES. In patient 1, three sessions of electrocautery treatments on both upper arms were performed with settings of short-fire mode (1–3 V) at 4- to 8-week intervals. After treatment, the lesions subsided but recurred 7 months later. Five months after recurrence, the rash gradually increased on the trunk and upper arms. In patient 2, two sessions of CO₂ laser treatments on the trunk were performed with settings of modulated pulse mode (1–2 W) at 4- to 8-week intervals. The lesions disappeared after treatment but recurred 6 months later. At 1-year follow-up after recurrence, the rash had increased slightly. Neither patient 1 nor patient 2 developed hyperpigmentation or scarring during the 1-year follow-up period after their respective treatments. Patient 3 opted not to undergo treatment after being informed that the lesions were benign, and his condition stabilized at 1-year follow-up.

The pathogenesis of ES is unclear, but it may be affected by hormones, autoimmune status, immunosuppression (eg, liver and kidney transplantation), and medications (eg, hypersensitivity, phototoxicity, and antiepileptic medications).^3-6 Guitart et al⁷ hypothesized that ES may be a hyperplastic response of the eccrine duct to an inflammatory reaction, such as trauma from waxing or chronic scratching. It also has been associated with systemic conditions such as Nicolau-Balus syndrome (syringomas, milia, and atrophoderma vermiculata) and Down syndrome.^8,9 The lesions manifest symmetrically and are characterized by flesh-colored to reddish-brown, shiny, or flat-topped papules; however, ES also can manifest as hyperpigmentation, erythema, positive Darier sign, or pseudokoebnerization.¹⁰ The lesions typically are located on the eyelids, neck, anterior chest, upper abdomen, upper arms, axillae, and genital region, and they rarely involve the palms, soles, and mucous membranes. Eruptive syringoma commonly is asymptomatic and in rare cases gradually subsides.¹¹

Sometimes the lesions of ES are atypical and clinically resemble Darier disease, Fox-Fordyce disease, lichen planus, mastocytosis, granuloma annulare, trichoepithelioma, and sarcoidosis. Additionally, Marfan syndrome and Ehlers-Danlos syndrome should be ruled out when lesions involve the eyelids.¹¹ The differential diagnosis in our patients included Darier disease and Fox-Fordyce disease, which can be differentiated from ES via noninvasive dermoscopy and pathologic biopsy. In most patients with ES, dermoscopic findings include reticular brown lines or fine pigment networks as well as dotted and linear or reticular vessels. Tiny whitish dots, multifocal hypopigmented areas, and glittering yellow-whitish round structures are dermoscopic hallmarks of the vulvar variant of ES.^12-14 Histopathology of ES has shown epithelial cords, ducts, and cystic structures within the dermis. The ducts are lined by 2 rows of epithelial cells with a characteristic comma-shaped/tadpolelike pattern and are filled with eosinophilic amorphous substances. The dermoscopic features of Darier disease differ from ES in that Darier disease usually manifests as a comedolike opening with a central polygonal yellowish-brownish structure surrounded by a whitish halo on a pink background.¹⁵Histopathology of Darier disease has shown acantholysis above the basal layer of the epidermis and dyskeratotic keratinocytes. Dermoscopic findings in Fox-Fordyce disease include typical light brown to dark brown, folliculocentric, structureless areas with loss of dermatoglyphics. Some of the lesions also show hyperkeratotic follicular plugging.¹⁶ Histopathology of Fox-Fordyce disease includes infundibulum dilation, hyperkeratosis, plugging, acanthosis, a lymphohistiocytic infiltrate, and a perifollicular foam cell infiltrate.¹⁷Eruptive syringoma is a benign condition that generally requires no treatment. The goal of treatment is to improve cosmesis and primarily includes physical and chemical therapies such as surgical resection, cryosurgery, electrodesiccation, CO₂ laser (alone and in combination with trichloroacetic acid¹⁰), argon laser, fractional photothermolysis, dermabrasion, and chemical peeling. However, because ES involves deeper areas of the dermis, some treatments may cause hyperpigmentation, scar formation, or recurrence of the lesions and may be less effective for lesions on the eyelids, which may remain untreated. Systemic therapy consists of oral retinoic acid or tranilast.¹⁸The use of topical retinoic acid and atropine also have been reported,¹⁹ but their efficacy remains uncertain. The lesions in patient 1 did not resolve after receiving oral and topical retinoic acid. Although ES lesions may decrease in size or subside without inter­vention in rare cases, the disease was not self-limiting in our patients.

To the Editor:

Syringoma is a relatively common benign adnexal neoplasm originating in the ducts of eccrine sweat glands. It can be divided into 4 variants based on clinical features: localized; familial; Down syndrome associated; and generalized, which includes multiple syringomas and eruptive syringoma (ES).¹ Eruptive syringoma is a rare variant of generalized syringoma that was first described by Jacquet and Darier² in 1887. Clinically, ES lesions manifest as multiple nonfused, flesh-colored to reddish-brown papules that are located most commonly on the anterior trunk during childhood or adolescence. Eruptive syringoma can be missed easily or misdiagnosed clinically. We present 3 rare cases of ES.

A 28-year-old man presented with multiple asymptomatic papules on the trunk and upper arms of 20 years’ duration (patient 1). He had been diagnosed with Darier disease 3 years prior to the current presentation and was treated with oral and topical retinoic acid without a response. After 3 months of oral treatment, the retinoic acid was stopped due to elevated liver enzymes. Physical examination at the current presentation revealed multiple smooth, firm, nonfused, 1- to 4-mm, reddish to dark red papules on the neck, chest, abdomen, and flexural surfaces of the upper arms (Figure 1A). Dermoscopy of the arm lesions showed light brown pigment networks and yellowish-white unstructured areas surrounded by linear vessels on a pink background under polarized light (Figure 1B). Histopathologic examination of a lesion on the left arm revealed epithelial cords, ducts, and cystic structures within the superficial and mid dermis. The ducts were lined by 2 rows of epithelial cells with a characteristic tadpolelike pattern and filled with eosinophilic amorphous substances (Figure 1C).

A 43-year-old man who was otherwise healthy presented with brownish flat-topped papules on the chest and abdomen of 19 years’ duration (Figure 3A)(patient 3). The lesions had remained stable and did not progress. He denied any treatment. Dermoscopy of the chest lesions showed a light brown pigment network as well as dotted and linear vessels on a pale yellow background (Figure 3B).

All 3 patients demonstrated classic histopathologic features of syringoma, and none had a family history of similar skin lesions. The clinical and dermoscopic findings along with the histopathology in all 3 patients were consistent with ES. In patient 1, three sessions of electrocautery treatments on both upper arms were performed with settings of short-fire mode (1–3 V) at 4- to 8-week intervals. After treatment, the lesions subsided but recurred 7 months later. Five months after recurrence, the rash gradually increased on the trunk and upper arms. In patient 2, two sessions of CO₂ laser treatments on the trunk were performed with settings of modulated pulse mode (1–2 W) at 4- to 8-week intervals. The lesions disappeared after treatment but recurred 6 months later. At 1-year follow-up after recurrence, the rash had increased slightly. Neither patient 1 nor patient 2 developed hyperpigmentation or scarring during the 1-year follow-up period after their respective treatments. Patient 3 opted not to undergo treatment after being informed that the lesions were benign, and his condition stabilized at 1-year follow-up.

The pathogenesis of ES is unclear, but it may be affected by hormones, autoimmune status, immunosuppression (eg, liver and kidney transplantation), and medications (eg, hypersensitivity, phototoxicity, and antiepileptic medications).^3-6 Guitart et al⁷ hypothesized that ES may be a hyperplastic response of the eccrine duct to an inflammatory reaction, such as trauma from waxing or chronic scratching. It also has been associated with systemic conditions such as Nicolau-Balus syndrome (syringomas, milia, and atrophoderma vermiculata) and Down syndrome.^8,9 The lesions manifest symmetrically and are characterized by flesh-colored to reddish-brown, shiny, or flat-topped papules; however, ES also can manifest as hyperpigmentation, erythema, positive Darier sign, or pseudokoebnerization.¹⁰ The lesions typically are located on the eyelids, neck, anterior chest, upper abdomen, upper arms, axillae, and genital region, and they rarely involve the palms, soles, and mucous membranes. Eruptive syringoma commonly is asymptomatic and in rare cases gradually subsides.¹¹

Sometimes the lesions of ES are atypical and clinically resemble Darier disease, Fox-Fordyce disease, lichen planus, mastocytosis, granuloma annulare, trichoepithelioma, and sarcoidosis. Additionally, Marfan syndrome and Ehlers-Danlos syndrome should be ruled out when lesions involve the eyelids.¹¹ The differential diagnosis in our patients included Darier disease and Fox-Fordyce disease, which can be differentiated from ES via noninvasive dermoscopy and pathologic biopsy. In most patients with ES, dermoscopic findings include reticular brown lines or fine pigment networks as well as dotted and linear or reticular vessels. Tiny whitish dots, multifocal hypopigmented areas, and glittering yellow-whitish round structures are dermoscopic hallmarks of the vulvar variant of ES.^12-14 Histopathology of ES has shown epithelial cords, ducts, and cystic structures within the dermis. The ducts are lined by 2 rows of epithelial cells with a characteristic comma-shaped/tadpolelike pattern and are filled with eosinophilic amorphous substances. The dermoscopic features of Darier disease differ from ES in that Darier disease usually manifests as a comedolike opening with a central polygonal yellowish-brownish structure surrounded by a whitish halo on a pink background.¹⁵Histopathology of Darier disease has shown acantholysis above the basal layer of the epidermis and dyskeratotic keratinocytes. Dermoscopic findings in Fox-Fordyce disease include typical light brown to dark brown, folliculocentric, structureless areas with loss of dermatoglyphics. Some of the lesions also show hyperkeratotic follicular plugging.¹⁶ Histopathology of Fox-Fordyce disease includes infundibulum dilation, hyperkeratosis, plugging, acanthosis, a lymphohistiocytic infiltrate, and a perifollicular foam cell infiltrate.¹⁷Eruptive syringoma is a benign condition that generally requires no treatment. The goal of treatment is to improve cosmesis and primarily includes physical and chemical therapies such as surgical resection, cryosurgery, electrodesiccation, CO₂ laser (alone and in combination with trichloroacetic acid¹⁰), argon laser, fractional photothermolysis, dermabrasion, and chemical peeling. However, because ES involves deeper areas of the dermis, some treatments may cause hyperpigmentation, scar formation, or recurrence of the lesions and may be less effective for lesions on the eyelids, which may remain untreated. Systemic therapy consists of oral retinoic acid or tranilast.¹⁸The use of topical retinoic acid and atropine also have been reported,¹⁹ but their efficacy remains uncertain. The lesions in patient 1 did not resolve after receiving oral and topical retinoic acid. Although ES lesions may decrease in size or subside without inter­vention in rare cases, the disease was not self-limiting in our patients.

To the Editor:

Syringoma is a relatively common benign adnexal neoplasm originating in the ducts of eccrine sweat glands. It can be divided into 4 variants based on clinical features: localized; familial; Down syndrome associated; and generalized, which includes multiple syringomas and eruptive syringoma (ES).¹ Eruptive syringoma is a rare variant of generalized syringoma that was first described by Jacquet and Darier² in 1887. Clinically, ES lesions manifest as multiple nonfused, flesh-colored to reddish-brown papules that are located most commonly on the anterior trunk during childhood or adolescence. Eruptive syringoma can be missed easily or misdiagnosed clinically. We present 3 rare cases of ES.

A 28-year-old man presented with multiple asymptomatic papules on the trunk and upper arms of 20 years’ duration (patient 1). He had been diagnosed with Darier disease 3 years prior to the current presentation and was treated with oral and topical retinoic acid without a response. After 3 months of oral treatment, the retinoic acid was stopped due to elevated liver enzymes. Physical examination at the current presentation revealed multiple smooth, firm, nonfused, 1- to 4-mm, reddish to dark red papules on the neck, chest, abdomen, and flexural surfaces of the upper arms (Figure 1A). Dermoscopy of the arm lesions showed light brown pigment networks and yellowish-white unstructured areas surrounded by linear vessels on a pink background under polarized light (Figure 1B). Histopathologic examination of a lesion on the left arm revealed epithelial cords, ducts, and cystic structures within the superficial and mid dermis. The ducts were lined by 2 rows of epithelial cells with a characteristic tadpolelike pattern and filled with eosinophilic amorphous substances (Figure 1C).

A 43-year-old man who was otherwise healthy presented with brownish flat-topped papules on the chest and abdomen of 19 years’ duration (Figure 3A)(patient 3). The lesions had remained stable and did not progress. He denied any treatment. Dermoscopy of the chest lesions showed a light brown pigment network as well as dotted and linear vessels on a pale yellow background (Figure 3B).

All 3 patients demonstrated classic histopathologic features of syringoma, and none had a family history of similar skin lesions. The clinical and dermoscopic findings along with the histopathology in all 3 patients were consistent with ES. In patient 1, three sessions of electrocautery treatments on both upper arms were performed with settings of short-fire mode (1–3 V) at 4- to 8-week intervals. After treatment, the lesions subsided but recurred 7 months later. Five months after recurrence, the rash gradually increased on the trunk and upper arms. In patient 2, two sessions of CO₂ laser treatments on the trunk were performed with settings of modulated pulse mode (1–2 W) at 4- to 8-week intervals. The lesions disappeared after treatment but recurred 6 months later. At 1-year follow-up after recurrence, the rash had increased slightly. Neither patient 1 nor patient 2 developed hyperpigmentation or scarring during the 1-year follow-up period after their respective treatments. Patient 3 opted not to undergo treatment after being informed that the lesions were benign, and his condition stabilized at 1-year follow-up.

The pathogenesis of ES is unclear, but it may be affected by hormones, autoimmune status, immunosuppression (eg, liver and kidney transplantation), and medications (eg, hypersensitivity, phototoxicity, and antiepileptic medications).^3-6 Guitart et al⁷ hypothesized that ES may be a hyperplastic response of the eccrine duct to an inflammatory reaction, such as trauma from waxing or chronic scratching. It also has been associated with systemic conditions such as Nicolau-Balus syndrome (syringomas, milia, and atrophoderma vermiculata) and Down syndrome.^8,9 The lesions manifest symmetrically and are characterized by flesh-colored to reddish-brown, shiny, or flat-topped papules; however, ES also can manifest as hyperpigmentation, erythema, positive Darier sign, or pseudokoebnerization.¹⁰ The lesions typically are located on the eyelids, neck, anterior chest, upper abdomen, upper arms, axillae, and genital region, and they rarely involve the palms, soles, and mucous membranes. Eruptive syringoma commonly is asymptomatic and in rare cases gradually subsides.¹¹

Sometimes the lesions of ES are atypical and clinically resemble Darier disease, Fox-Fordyce disease, lichen planus, mastocytosis, granuloma annulare, trichoepithelioma, and sarcoidosis. Additionally, Marfan syndrome and Ehlers-Danlos syndrome should be ruled out when lesions involve the eyelids.¹¹ The differential diagnosis in our patients included Darier disease and Fox-Fordyce disease, which can be differentiated from ES via noninvasive dermoscopy and pathologic biopsy. In most patients with ES, dermoscopic findings include reticular brown lines or fine pigment networks as well as dotted and linear or reticular vessels. Tiny whitish dots, multifocal hypopigmented areas, and glittering yellow-whitish round structures are dermoscopic hallmarks of the vulvar variant of ES.^12-14 Histopathology of ES has shown epithelial cords, ducts, and cystic structures within the dermis. The ducts are lined by 2 rows of epithelial cells with a characteristic comma-shaped/tadpolelike pattern and are filled with eosinophilic amorphous substances. The dermoscopic features of Darier disease differ from ES in that Darier disease usually manifests as a comedolike opening with a central polygonal yellowish-brownish structure surrounded by a whitish halo on a pink background.¹⁵Histopathology of Darier disease has shown acantholysis above the basal layer of the epidermis and dyskeratotic keratinocytes. Dermoscopic findings in Fox-Fordyce disease include typical light brown to dark brown, folliculocentric, structureless areas with loss of dermatoglyphics. Some of the lesions also show hyperkeratotic follicular plugging.¹⁶ Histopathology of Fox-Fordyce disease includes infundibulum dilation, hyperkeratosis, plugging, acanthosis, a lymphohistiocytic infiltrate, and a perifollicular foam cell infiltrate.¹⁷Eruptive syringoma is a benign condition that generally requires no treatment. The goal of treatment is to improve cosmesis and primarily includes physical and chemical therapies such as surgical resection, cryosurgery, electrodesiccation, CO₂ laser (alone and in combination with trichloroacetic acid¹⁰), argon laser, fractional photothermolysis, dermabrasion, and chemical peeling. However, because ES involves deeper areas of the dermis, some treatments may cause hyperpigmentation, scar formation, or recurrence of the lesions and may be less effective for lesions on the eyelids, which may remain untreated. Systemic therapy consists of oral retinoic acid or tranilast.¹⁸The use of topical retinoic acid and atropine also have been reported,¹⁹ but their efficacy remains uncertain. The lesions in patient 1 did not resolve after receiving oral and topical retinoic acid. Although ES lesions may decrease in size or subside without inter­vention in rare cases, the disease was not self-limiting in our patients.

To the Editor:

Hidradenitis suppurativa (HS) is a multifactorial chronic inflammatory skin disease affecting 1% to 4% of Europeans. It is characterized by recurrent inflamed nodules, abscesses, and sinus tracts in intertriginous regions.¹ The genital area is affected in 11% of cases² and usually is connected to severe forms of HS in both men and women.³ The prevalence of HS-associated genital lymphedema remains unknown.

Saxophone penis is a specific penile malformation characterized by a saxophone shape due to inflammation of the major penile lymphatic vessels that cause fibrosis of the surrounding connective tissue. Poor blood flow further causes contracture and distortion of the penile axis.⁴ Saxophone penis also has been associated with primary lymphedema, lymphogranuloma venereum, filariasis,⁵ and administration of paraffin injections.⁶ We describe 3 men with HS who presented with saxophone penis.

A 33-year-old man with Hurley stage III HS presented with a medical history of groin lesions and progressive penoscrotal edema of 13 years’ duration. He had a body mass index (BMI) of 37, no family history of HS or comorbidities, and a 15-year history of smoking 20 cigarettes per day. After repeated surgical drainage of the HS lesions as well as antibiotic treatment with clindamycin 600 mg/d and rifampicin 600 mg/d, the patient was kept on a maintenance therapy with adalimumab 40 mg/wk. Due to lack of response, treatment was discontinued at week 16. Clindamycin and ­rifampicin 300 mg were immediately reintroduced with no benefit on the genital lesions. The patient underwent genital reconstruction, including penile degloving, scrotoplasty, infrapubic fat pad removal, and perineoplasty (Figure 1). The patient currently is not undergoing any therapies.

A 55-year-old man presented with Hurley stage II HS of 33 years’ duration. He had a BMI of 52; a history of hypertension, hyperuricemia, severe hip and knee osteoarthritis, and orchiopexy in childhood; a smoking history of 40 cigarettes per day; and an alcohol consumption history of 200 mL per day since 18 years of age. He had radical excision of axillary lesions 8 years prior. One year later, he was treated with concomitant clindamycin and rifampicin 300 mg twice daily for 3 months with no desirable effects. Adalimumab 40 mg/wk was initiated. After 12 weeks of treatment, he experienced 80% improvement in all areas except the genital region. He continued adalimumab for 3 years with good clinical response in all HS-affected sites except the genital region.

A 66-year-old man presented with Hurley stage III HS of 37 years’ duration. He had a smoking history of 10 cigarettes per day for 30 years, a BMI of 24.6, and a medical history of long-standing hypertension and hypothyroidism. A 3-month course of clindamycin and rifampicin 600 mg/d was ineffective; adalimumab 40 mg/wk was initiated. All affected areas improved, except for the saxophone penis. He continues his fifth year of therapy with adalimumab (Figure 2).

Hidradenitis suppurativa is associated with chronic pain, purulent malodor, and scarring with structural deformity. Repetitive inflammation causes fibrosis, scar formation, and soft-tissue destruction of lymphatic vessels, leading to lymphedema; primary lymphedema of the genitals in men has been reported to result in a saxophone penis.⁴

The only approved biologic treatments for moderate to severe HS are the tumor necrosis factor α inhibitor adalimumab and anti-IL-17 secukinumab.¹ All 3 of our patients with HS were treated with adalimumab with reasonable success; however, the penile condition remained refractory, which we speculate may be due to adalimumab’s ability to control only active inflammatory lesions but not scars or fibrotic tissue.⁷ Higher adalimumab dosages were unlikely to be beneficial for their penile condition; some improvements have been reported following fluoroquinolone therapy. To our knowledge, there is no effective medical treatment for saxophone penis. However, surgery showed good results in one of our patients. Among our 3 adalimumab-treated patients, only 1 patient had corrective surgery that resulted in improvement in the penile deformity, further confirming adalimumab’s limited role in genital lymphedema.⁷ Extensive resection of the lymphedematous tissue, scrotoplasty, and Charles procedure are treatment options.⁸

Genital lymphedema has been associated with lymphangiectasia, lymphangioma circumscriptum, infections, and neoplasms such as lymphangiosarcoma and squamous cell carcinoma.⁹ Our patients reported discomfort, hygiene issues, and swelling. One patient reported micturition, and 2 patients reported sexual dysfunction.

Saxophone penis remains a disabling sequela of HS. Early diagnosis and treatment of HS may help prevent development of this condition.

To the Editor:

Hidradenitis suppurativa (HS) is a multifactorial chronic inflammatory skin disease affecting 1% to 4% of Europeans. It is characterized by recurrent inflamed nodules, abscesses, and sinus tracts in intertriginous regions.¹ The genital area is affected in 11% of cases² and usually is connected to severe forms of HS in both men and women.³ The prevalence of HS-associated genital lymphedema remains unknown.

Saxophone penis is a specific penile malformation characterized by a saxophone shape due to inflammation of the major penile lymphatic vessels that cause fibrosis of the surrounding connective tissue. Poor blood flow further causes contracture and distortion of the penile axis.⁴ Saxophone penis also has been associated with primary lymphedema, lymphogranuloma venereum, filariasis,⁵ and administration of paraffin injections.⁶ We describe 3 men with HS who presented with saxophone penis.

A 33-year-old man with Hurley stage III HS presented with a medical history of groin lesions and progressive penoscrotal edema of 13 years’ duration. He had a body mass index (BMI) of 37, no family history of HS or comorbidities, and a 15-year history of smoking 20 cigarettes per day. After repeated surgical drainage of the HS lesions as well as antibiotic treatment with clindamycin 600 mg/d and rifampicin 600 mg/d, the patient was kept on a maintenance therapy with adalimumab 40 mg/wk. Due to lack of response, treatment was discontinued at week 16. Clindamycin and ­rifampicin 300 mg were immediately reintroduced with no benefit on the genital lesions. The patient underwent genital reconstruction, including penile degloving, scrotoplasty, infrapubic fat pad removal, and perineoplasty (Figure 1). The patient currently is not undergoing any therapies.

A 55-year-old man presented with Hurley stage II HS of 33 years’ duration. He had a BMI of 52; a history of hypertension, hyperuricemia, severe hip and knee osteoarthritis, and orchiopexy in childhood; a smoking history of 40 cigarettes per day; and an alcohol consumption history of 200 mL per day since 18 years of age. He had radical excision of axillary lesions 8 years prior. One year later, he was treated with concomitant clindamycin and rifampicin 300 mg twice daily for 3 months with no desirable effects. Adalimumab 40 mg/wk was initiated. After 12 weeks of treatment, he experienced 80% improvement in all areas except the genital region. He continued adalimumab for 3 years with good clinical response in all HS-affected sites except the genital region.

A 66-year-old man presented with Hurley stage III HS of 37 years’ duration. He had a smoking history of 10 cigarettes per day for 30 years, a BMI of 24.6, and a medical history of long-standing hypertension and hypothyroidism. A 3-month course of clindamycin and rifampicin 600 mg/d was ineffective; adalimumab 40 mg/wk was initiated. All affected areas improved, except for the saxophone penis. He continues his fifth year of therapy with adalimumab (Figure 2).

Hidradenitis suppurativa is associated with chronic pain, purulent malodor, and scarring with structural deformity. Repetitive inflammation causes fibrosis, scar formation, and soft-tissue destruction of lymphatic vessels, leading to lymphedema; primary lymphedema of the genitals in men has been reported to result in a saxophone penis.⁴

The only approved biologic treatments for moderate to severe HS are the tumor necrosis factor α inhibitor adalimumab and anti-IL-17 secukinumab.¹ All 3 of our patients with HS were treated with adalimumab with reasonable success; however, the penile condition remained refractory, which we speculate may be due to adalimumab’s ability to control only active inflammatory lesions but not scars or fibrotic tissue.⁷ Higher adalimumab dosages were unlikely to be beneficial for their penile condition; some improvements have been reported following fluoroquinolone therapy. To our knowledge, there is no effective medical treatment for saxophone penis. However, surgery showed good results in one of our patients. Among our 3 adalimumab-treated patients, only 1 patient had corrective surgery that resulted in improvement in the penile deformity, further confirming adalimumab’s limited role in genital lymphedema.⁷ Extensive resection of the lymphedematous tissue, scrotoplasty, and Charles procedure are treatment options.⁸

Genital lymphedema has been associated with lymphangiectasia, lymphangioma circumscriptum, infections, and neoplasms such as lymphangiosarcoma and squamous cell carcinoma.⁹ Our patients reported discomfort, hygiene issues, and swelling. One patient reported micturition, and 2 patients reported sexual dysfunction.

Saxophone penis remains a disabling sequela of HS. Early diagnosis and treatment of HS may help prevent development of this condition.

To the Editor:

Hidradenitis suppurativa (HS) is a multifactorial chronic inflammatory skin disease affecting 1% to 4% of Europeans. It is characterized by recurrent inflamed nodules, abscesses, and sinus tracts in intertriginous regions.¹ The genital area is affected in 11% of cases² and usually is connected to severe forms of HS in both men and women.³ The prevalence of HS-associated genital lymphedema remains unknown.

Saxophone penis is a specific penile malformation characterized by a saxophone shape due to inflammation of the major penile lymphatic vessels that cause fibrosis of the surrounding connective tissue. Poor blood flow further causes contracture and distortion of the penile axis.⁴ Saxophone penis also has been associated with primary lymphedema, lymphogranuloma venereum, filariasis,⁵ and administration of paraffin injections.⁶ We describe 3 men with HS who presented with saxophone penis.

A 33-year-old man with Hurley stage III HS presented with a medical history of groin lesions and progressive penoscrotal edema of 13 years’ duration. He had a body mass index (BMI) of 37, no family history of HS or comorbidities, and a 15-year history of smoking 20 cigarettes per day. After repeated surgical drainage of the HS lesions as well as antibiotic treatment with clindamycin 600 mg/d and rifampicin 600 mg/d, the patient was kept on a maintenance therapy with adalimumab 40 mg/wk. Due to lack of response, treatment was discontinued at week 16. Clindamycin and ­rifampicin 300 mg were immediately reintroduced with no benefit on the genital lesions. The patient underwent genital reconstruction, including penile degloving, scrotoplasty, infrapubic fat pad removal, and perineoplasty (Figure 1). The patient currently is not undergoing any therapies.

A 55-year-old man presented with Hurley stage II HS of 33 years’ duration. He had a BMI of 52; a history of hypertension, hyperuricemia, severe hip and knee osteoarthritis, and orchiopexy in childhood; a smoking history of 40 cigarettes per day; and an alcohol consumption history of 200 mL per day since 18 years of age. He had radical excision of axillary lesions 8 years prior. One year later, he was treated with concomitant clindamycin and rifampicin 300 mg twice daily for 3 months with no desirable effects. Adalimumab 40 mg/wk was initiated. After 12 weeks of treatment, he experienced 80% improvement in all areas except the genital region. He continued adalimumab for 3 years with good clinical response in all HS-affected sites except the genital region.

A 66-year-old man presented with Hurley stage III HS of 37 years’ duration. He had a smoking history of 10 cigarettes per day for 30 years, a BMI of 24.6, and a medical history of long-standing hypertension and hypothyroidism. A 3-month course of clindamycin and rifampicin 600 mg/d was ineffective; adalimumab 40 mg/wk was initiated. All affected areas improved, except for the saxophone penis. He continues his fifth year of therapy with adalimumab (Figure 2).

Hidradenitis suppurativa is associated with chronic pain, purulent malodor, and scarring with structural deformity. Repetitive inflammation causes fibrosis, scar formation, and soft-tissue destruction of lymphatic vessels, leading to lymphedema; primary lymphedema of the genitals in men has been reported to result in a saxophone penis.⁴

The only approved biologic treatments for moderate to severe HS are the tumor necrosis factor α inhibitor adalimumab and anti-IL-17 secukinumab.¹ All 3 of our patients with HS were treated with adalimumab with reasonable success; however, the penile condition remained refractory, which we speculate may be due to adalimumab’s ability to control only active inflammatory lesions but not scars or fibrotic tissue.⁷ Higher adalimumab dosages were unlikely to be beneficial for their penile condition; some improvements have been reported following fluoroquinolone therapy. To our knowledge, there is no effective medical treatment for saxophone penis. However, surgery showed good results in one of our patients. Among our 3 adalimumab-treated patients, only 1 patient had corrective surgery that resulted in improvement in the penile deformity, further confirming adalimumab’s limited role in genital lymphedema.⁷ Extensive resection of the lymphedematous tissue, scrotoplasty, and Charles procedure are treatment options.⁸

Genital lymphedema has been associated with lymphangiectasia, lymphangioma circumscriptum, infections, and neoplasms such as lymphangiosarcoma and squamous cell carcinoma.⁹ Our patients reported discomfort, hygiene issues, and swelling. One patient reported micturition, and 2 patients reported sexual dysfunction.

Saxophone penis remains a disabling sequela of HS. Early diagnosis and treatment of HS may help prevent development of this condition.

To the Editor:

Henoch-Schönlein purpura (HSP)(also known as IgA vasculitis) is a small vessel vasculitis characterized by deposition of IgA in small vessels, resulting in the development of purpura on the legs. Based on the European Alliance of Associations for Rheumatology criteria,¹ the patient also must have at least 1 of the following: arthritis, arthralgia, abdominal pain, leukocytoclastic vasculitis with IgA deposition, or kidney involvement. The disease can be triggered by infection—with more than 75% of patients reporting an antecedent upper respiratory tract infection²—as well as medications, circulating immune complexes, certain foods, vaccines, and rarely cancer.^3,4 The disease more commonly occurs in children but also can affect adults.

Several cases of HSP have been reported following COVID-19 vaccination.⁵ We report a case of HSP developing days after the messenger RNA Pfizer-BioNTech COVID-19 vaccine booster that was associated with anti-Smith and anti–double-stranded DNA (dsDNA) antibodies as well as antineutrophil cytoplasmic antibodies (ANCAs).

A 24-year-old man presented to dermatology with a rash of 3 weeks’ duration that first appeared 1 week after receiving his second booster of the messenger RNA Pfizer-BioNTech COVID-19 vaccine. Physical examination revealed petechiae with nonblanching erythematous macules and papules covering the legs below the knees (Figure 1) as well as the back of the right arm. A few days later, he developed arthralgia in the knees, hands, and feet. The patient denied any recent infections as well as respiratory and urinary tract symptoms. Approximately 10 days after the rash appeared, he developed epigastric abdominal pain that gradually worsened and sought care from his primary care physician, who ordered computed tomography and referred him for endoscopy. Computed tomography with and without contrast was suspicious for colitis. Colonoscopy and endoscopy were unremarkable. Laboratory tests were notable for elevated white blood cell count (17.08×10³/µL [reference range, 3.66–10.60×10³/µL]), serum IgA (437 mg/dL [reference range, 70–400 mg/dL]), C-reactive protein (1.5 mg/dL [reference range, <0.5 mg/dL]), anti-Smith antibody (28.1 CU [reference range, <20 CU), positive antinuclear antibody with titer (1:160 [reference range, <1:80]), anti-dsDNA (40.4 IU/mL [reference range, <27 IU/mL]), and cytoplasmic ANCA (c-ANCA) titer (1:320 [reference range, <1:20]). Blood urea nitrogen, creatinine, and estimated glomerular filtration rate were all within reference range. Urinalysis with microscopic examination was notable for 2 to 5 red blood cells per high-power field (reference range, 0) and proteinuria of 1+ (reference range, negative for protein).

The patient’s rash progressively worsened over the next few weeks, spreading proximally on the legs to the buttocks and the back of both elbows. A repeat complete blood cell count showed resolution of the leukocytosis. Two biopsies were taken from a lesion on the left proximal thigh: 1 for hematoxylin and eosin stain for histopathologic examination and 1 for direct immunofluorescence examination.

The patient was preliminarily diagnosed with HSP, and dermatology prescribed oral tofacitinib 5 mg twice daily for 5 days, which was supposed to be increased to 10 mg twice daily on the sixth day of treatment; however, the patient discontinued the medication after 4 days based on his primary care physician’s recommendation due to clotting concerns. The rash and arthralgia temporarily improved for 1 week, then relapsed.

Histopathology revealed neutrophils surrounding and infiltrating small dermal blood vessel walls as well as associated neutrophilic debris and erythrocytes, consistent with leukocytoclastic vasculitis (Figure 2). Direct immunofluorescence was negative for IgA antibodies. His primary care physician, in consultation with his dermatologist, then started the patient on oral prednisone 70 mg once daily for 7 days with a plan to taper. Three days after prednisone was started, the arthralgia and abdominal pain resolved, and the rash became lighter in color. After 1 week, the rash resolved completely.

Due to the unusual antibodies, the patient was referred to a rheumatologist, who repeated the blood tests approximately 1 week after the patient started prednisone. The tests were negative for anti-Smith, anti-dsDNA, and c-ANCA but showed an elevated atypical perinuclear ANCA (p-ANCA) titer of 1:80 (reference range [negative], <1:20). A repeat urinalysis was unremarkable. The patient slowly tapered the prednisone over the course of 3 months and was subsequently lost to follow-up. The rash and other symptoms had not recurred as of the patient’s last physician contact. The most recent laboratory results showed a white blood cell count of 14.0×10³/µL (reference range, 3.4–10.8×10³/µL), likely due to the prednisone; blood urea nitrogen, creatinine, and estimated glomerular filtration rate were within reference range. The urinalysis was notable for occult blood and was negative for protein. C-reactive protein was 1 mg/dL (reference range, 0–10 mg/dL); p-ANCA, c-ANCA, and atypical p-ANCA, as well as antinuclear antibody, were negative. As of his last follow-up, the patient felt well.

The major differential diagnoses for our patient included HSP, ANCA vasculitis, and systemic lupus erythematosus. Although ANCA vasculitis has been reported after SARS-CoV-2 infection,⁶ the lack of pulmonary symptoms made this diagnosis unlikely.⁷ Although our patient initially had elevated anti-Smith and anti-dsDNA antibodies as well as mild renal involvement, he fulfilled at most only 2 of the 11 criteria necessary for diagnosing lupus: malar rash, discoid rash (includes alopecia), photosensitivity, ocular ulcers, nonerosive arthritis, serositis, renal disorder (protein >500 mg/24 h, red blood cells, casts), neurologic disorder (seizures, psychosis), hematologic disorders (hemolytic anemia, leukopenia), ANA, and immunologic disorder (anti-Smith). Four of the 11 criteria are necessary for the diagnosis of lupus.⁸

Torraca et al⁷ reported a case of HSP with positive c-ANCA (1:640) in a patient lacking pulmonary symptoms who was diagnosed with HSP. Cytoplasmic ANCA is not a typical finding in HSP. However, the additional findings of anti-Smith, anti-dsDNA, and mildly elevated atypical p-ANCA antibodies in our patient were unexpected and could be explained by the proposed pathogenesis of HSP—an overzealous immune response resulting in aberrant antibody complex deposition with ensuing complement activation.^5,9 Production of these additional antibodies could be part of the overzealous response to COVID-19 vaccination.

Acknowledgment—We thank our patient for granting permission to publish this information.

To the Editor:

Henoch-Schönlein purpura (HSP)(also known as IgA vasculitis) is a small vessel vasculitis characterized by deposition of IgA in small vessels, resulting in the development of purpura on the legs. Based on the European Alliance of Associations for Rheumatology criteria,¹ the patient also must have at least 1 of the following: arthritis, arthralgia, abdominal pain, leukocytoclastic vasculitis with IgA deposition, or kidney involvement. The disease can be triggered by infection—with more than 75% of patients reporting an antecedent upper respiratory tract infection²—as well as medications, circulating immune complexes, certain foods, vaccines, and rarely cancer.^3,4 The disease more commonly occurs in children but also can affect adults.

Several cases of HSP have been reported following COVID-19 vaccination.⁵ We report a case of HSP developing days after the messenger RNA Pfizer-BioNTech COVID-19 vaccine booster that was associated with anti-Smith and anti–double-stranded DNA (dsDNA) antibodies as well as antineutrophil cytoplasmic antibodies (ANCAs).

A 24-year-old man presented to dermatology with a rash of 3 weeks’ duration that first appeared 1 week after receiving his second booster of the messenger RNA Pfizer-BioNTech COVID-19 vaccine. Physical examination revealed petechiae with nonblanching erythematous macules and papules covering the legs below the knees (Figure 1) as well as the back of the right arm. A few days later, he developed arthralgia in the knees, hands, and feet. The patient denied any recent infections as well as respiratory and urinary tract symptoms. Approximately 10 days after the rash appeared, he developed epigastric abdominal pain that gradually worsened and sought care from his primary care physician, who ordered computed tomography and referred him for endoscopy. Computed tomography with and without contrast was suspicious for colitis. Colonoscopy and endoscopy were unremarkable. Laboratory tests were notable for elevated white blood cell count (17.08×10³/µL [reference range, 3.66–10.60×10³/µL]), serum IgA (437 mg/dL [reference range, 70–400 mg/dL]), C-reactive protein (1.5 mg/dL [reference range, <0.5 mg/dL]), anti-Smith antibody (28.1 CU [reference range, <20 CU), positive antinuclear antibody with titer (1:160 [reference range, <1:80]), anti-dsDNA (40.4 IU/mL [reference range, <27 IU/mL]), and cytoplasmic ANCA (c-ANCA) titer (1:320 [reference range, <1:20]). Blood urea nitrogen, creatinine, and estimated glomerular filtration rate were all within reference range. Urinalysis with microscopic examination was notable for 2 to 5 red blood cells per high-power field (reference range, 0) and proteinuria of 1+ (reference range, negative for protein).

The patient’s rash progressively worsened over the next few weeks, spreading proximally on the legs to the buttocks and the back of both elbows. A repeat complete blood cell count showed resolution of the leukocytosis. Two biopsies were taken from a lesion on the left proximal thigh: 1 for hematoxylin and eosin stain for histopathologic examination and 1 for direct immunofluorescence examination.

The patient was preliminarily diagnosed with HSP, and dermatology prescribed oral tofacitinib 5 mg twice daily for 5 days, which was supposed to be increased to 10 mg twice daily on the sixth day of treatment; however, the patient discontinued the medication after 4 days based on his primary care physician’s recommendation due to clotting concerns. The rash and arthralgia temporarily improved for 1 week, then relapsed.

Histopathology revealed neutrophils surrounding and infiltrating small dermal blood vessel walls as well as associated neutrophilic debris and erythrocytes, consistent with leukocytoclastic vasculitis (Figure 2). Direct immunofluorescence was negative for IgA antibodies. His primary care physician, in consultation with his dermatologist, then started the patient on oral prednisone 70 mg once daily for 7 days with a plan to taper. Three days after prednisone was started, the arthralgia and abdominal pain resolved, and the rash became lighter in color. After 1 week, the rash resolved completely.

Due to the unusual antibodies, the patient was referred to a rheumatologist, who repeated the blood tests approximately 1 week after the patient started prednisone. The tests were negative for anti-Smith, anti-dsDNA, and c-ANCA but showed an elevated atypical perinuclear ANCA (p-ANCA) titer of 1:80 (reference range [negative], <1:20). A repeat urinalysis was unremarkable. The patient slowly tapered the prednisone over the course of 3 months and was subsequently lost to follow-up. The rash and other symptoms had not recurred as of the patient’s last physician contact. The most recent laboratory results showed a white blood cell count of 14.0×10³/µL (reference range, 3.4–10.8×10³/µL), likely due to the prednisone; blood urea nitrogen, creatinine, and estimated glomerular filtration rate were within reference range. The urinalysis was notable for occult blood and was negative for protein. C-reactive protein was 1 mg/dL (reference range, 0–10 mg/dL); p-ANCA, c-ANCA, and atypical p-ANCA, as well as antinuclear antibody, were negative. As of his last follow-up, the patient felt well.

The major differential diagnoses for our patient included HSP, ANCA vasculitis, and systemic lupus erythematosus. Although ANCA vasculitis has been reported after SARS-CoV-2 infection,⁶ the lack of pulmonary symptoms made this diagnosis unlikely.⁷ Although our patient initially had elevated anti-Smith and anti-dsDNA antibodies as well as mild renal involvement, he fulfilled at most only 2 of the 11 criteria necessary for diagnosing lupus: malar rash, discoid rash (includes alopecia), photosensitivity, ocular ulcers, nonerosive arthritis, serositis, renal disorder (protein >500 mg/24 h, red blood cells, casts), neurologic disorder (seizures, psychosis), hematologic disorders (hemolytic anemia, leukopenia), ANA, and immunologic disorder (anti-Smith). Four of the 11 criteria are necessary for the diagnosis of lupus.⁸

Torraca et al⁷ reported a case of HSP with positive c-ANCA (1:640) in a patient lacking pulmonary symptoms who was diagnosed with HSP. Cytoplasmic ANCA is not a typical finding in HSP. However, the additional findings of anti-Smith, anti-dsDNA, and mildly elevated atypical p-ANCA antibodies in our patient were unexpected and could be explained by the proposed pathogenesis of HSP—an overzealous immune response resulting in aberrant antibody complex deposition with ensuing complement activation.^5,9 Production of these additional antibodies could be part of the overzealous response to COVID-19 vaccination.

Acknowledgment—We thank our patient for granting permission to publish this information.

To the Editor:

Henoch-Schönlein purpura (HSP)(also known as IgA vasculitis) is a small vessel vasculitis characterized by deposition of IgA in small vessels, resulting in the development of purpura on the legs. Based on the European Alliance of Associations for Rheumatology criteria,¹ the patient also must have at least 1 of the following: arthritis, arthralgia, abdominal pain, leukocytoclastic vasculitis with IgA deposition, or kidney involvement. The disease can be triggered by infection—with more than 75% of patients reporting an antecedent upper respiratory tract infection²—as well as medications, circulating immune complexes, certain foods, vaccines, and rarely cancer.^3,4 The disease more commonly occurs in children but also can affect adults.

Several cases of HSP have been reported following COVID-19 vaccination.⁵ We report a case of HSP developing days after the messenger RNA Pfizer-BioNTech COVID-19 vaccine booster that was associated with anti-Smith and anti–double-stranded DNA (dsDNA) antibodies as well as antineutrophil cytoplasmic antibodies (ANCAs).

A 24-year-old man presented to dermatology with a rash of 3 weeks’ duration that first appeared 1 week after receiving his second booster of the messenger RNA Pfizer-BioNTech COVID-19 vaccine. Physical examination revealed petechiae with nonblanching erythematous macules and papules covering the legs below the knees (Figure 1) as well as the back of the right arm. A few days later, he developed arthralgia in the knees, hands, and feet. The patient denied any recent infections as well as respiratory and urinary tract symptoms. Approximately 10 days after the rash appeared, he developed epigastric abdominal pain that gradually worsened and sought care from his primary care physician, who ordered computed tomography and referred him for endoscopy. Computed tomography with and without contrast was suspicious for colitis. Colonoscopy and endoscopy were unremarkable. Laboratory tests were notable for elevated white blood cell count (17.08×10³/µL [reference range, 3.66–10.60×10³/µL]), serum IgA (437 mg/dL [reference range, 70–400 mg/dL]), C-reactive protein (1.5 mg/dL [reference range, <0.5 mg/dL]), anti-Smith antibody (28.1 CU [reference range, <20 CU), positive antinuclear antibody with titer (1:160 [reference range, <1:80]), anti-dsDNA (40.4 IU/mL [reference range, <27 IU/mL]), and cytoplasmic ANCA (c-ANCA) titer (1:320 [reference range, <1:20]). Blood urea nitrogen, creatinine, and estimated glomerular filtration rate were all within reference range. Urinalysis with microscopic examination was notable for 2 to 5 red blood cells per high-power field (reference range, 0) and proteinuria of 1+ (reference range, negative for protein).

The patient’s rash progressively worsened over the next few weeks, spreading proximally on the legs to the buttocks and the back of both elbows. A repeat complete blood cell count showed resolution of the leukocytosis. Two biopsies were taken from a lesion on the left proximal thigh: 1 for hematoxylin and eosin stain for histopathologic examination and 1 for direct immunofluorescence examination.

The patient was preliminarily diagnosed with HSP, and dermatology prescribed oral tofacitinib 5 mg twice daily for 5 days, which was supposed to be increased to 10 mg twice daily on the sixth day of treatment; however, the patient discontinued the medication after 4 days based on his primary care physician’s recommendation due to clotting concerns. The rash and arthralgia temporarily improved for 1 week, then relapsed.

Histopathology revealed neutrophils surrounding and infiltrating small dermal blood vessel walls as well as associated neutrophilic debris and erythrocytes, consistent with leukocytoclastic vasculitis (Figure 2). Direct immunofluorescence was negative for IgA antibodies. His primary care physician, in consultation with his dermatologist, then started the patient on oral prednisone 70 mg once daily for 7 days with a plan to taper. Three days after prednisone was started, the arthralgia and abdominal pain resolved, and the rash became lighter in color. After 1 week, the rash resolved completely.

Due to the unusual antibodies, the patient was referred to a rheumatologist, who repeated the blood tests approximately 1 week after the patient started prednisone. The tests were negative for anti-Smith, anti-dsDNA, and c-ANCA but showed an elevated atypical perinuclear ANCA (p-ANCA) titer of 1:80 (reference range [negative], <1:20). A repeat urinalysis was unremarkable. The patient slowly tapered the prednisone over the course of 3 months and was subsequently lost to follow-up. The rash and other symptoms had not recurred as of the patient’s last physician contact. The most recent laboratory results showed a white blood cell count of 14.0×10³/µL (reference range, 3.4–10.8×10³/µL), likely due to the prednisone; blood urea nitrogen, creatinine, and estimated glomerular filtration rate were within reference range. The urinalysis was notable for occult blood and was negative for protein. C-reactive protein was 1 mg/dL (reference range, 0–10 mg/dL); p-ANCA, c-ANCA, and atypical p-ANCA, as well as antinuclear antibody, were negative. As of his last follow-up, the patient felt well.

The major differential diagnoses for our patient included HSP, ANCA vasculitis, and systemic lupus erythematosus. Although ANCA vasculitis has been reported after SARS-CoV-2 infection,⁶ the lack of pulmonary symptoms made this diagnosis unlikely.⁷ Although our patient initially had elevated anti-Smith and anti-dsDNA antibodies as well as mild renal involvement, he fulfilled at most only 2 of the 11 criteria necessary for diagnosing lupus: malar rash, discoid rash (includes alopecia), photosensitivity, ocular ulcers, nonerosive arthritis, serositis, renal disorder (protein >500 mg/24 h, red blood cells, casts), neurologic disorder (seizures, psychosis), hematologic disorders (hemolytic anemia, leukopenia), ANA, and immunologic disorder (anti-Smith). Four of the 11 criteria are necessary for the diagnosis of lupus.⁸

Torraca et al⁷ reported a case of HSP with positive c-ANCA (1:640) in a patient lacking pulmonary symptoms who was diagnosed with HSP. Cytoplasmic ANCA is not a typical finding in HSP. However, the additional findings of anti-Smith, anti-dsDNA, and mildly elevated atypical p-ANCA antibodies in our patient were unexpected and could be explained by the proposed pathogenesis of HSP—an overzealous immune response resulting in aberrant antibody complex deposition with ensuing complement activation.^5,9 Production of these additional antibodies could be part of the overzealous response to COVID-19 vaccination.

Acknowledgment—We thank our patient for granting permission to publish this information.