Cutis

Pseudofolliculitis barbae (PFB)(also known as razor bumps or shaving bumps)¹ is a skin condition that consists of papules resulting from ingrown hairs.² In more severe cases, papules become pustules, then abscesses, which can cause scarring.^1,2 The condition can be distressing for patients, with considerable negative impact on their daily lives.³ The condition also is associated with shaving-related stinging, burning, pruritus, and cuts on the skin.⁴

Pseudofolliculitis barbae is most common in men of African descent due to the curved nature of the hair follicle,^2,5,6 with an estimated prevalence in this population of 45% to 83%,^1,6 but it can affect men of other ethnicities.⁷ A genetic polymorphism in a gene encoding a keratin specific to the hair follicle also has been found to predispose some individuals to PFB.⁵ When hair from a curved or destabilized hair follicle is cut to form a sharp tip, it is susceptible to extrafollicular and/or transfollicular penetration,^5,6,8 as illustrated in Figure 1.

With extrafollicular or transfollicular penetration, the hair shaft re-enters or retracts into the dermis, triggering an inflammatory response that may be exacerbated by subsequent shaving.² Few studies have been published that aim to identify potential shaving solutions for individuals with PFB who elect to or need to continue shaving.

A new razor technology comprising 2 blades separated by a bridge feature has been designed specifically for men with razor bumps (SkinGuard [Procter & Gamble]). The SkinGuard razor redistributes shaving pressure so that there is less force from the blades on the skin and inflamed lesions than without the bridge, as seen in Figure 2. The razor has been designed to protect the skin from the blades, thereby minimizing the occurrence of new lesions and allowing existing lesions to heal.

The primary purpose of this study was to assess the appearance of males with razor bumps and shaving irritation when using the new razor technology in a regular shaving routine. The secondary objective was to measure satisfaction of the shaving experience when using the new razor by means of assessing itching, burning, and stinging using the participant global severity assessment (PGSA) and the impact on quality of life (QOL) measures.

Methods

Participants—Eligible participants were male, aged 20 to 60 years, and had clinically diagnosed PFB as well as symptoms of skin irritation from shaving. Participants were recruited from a dermatology clinic and via institutional review board–approved advertising.

Those eligible for inclusion in the study had a shaving routine that comprised shaving at least 3 times a week using a wet-shave, blade-razor technique accompanied by only a shave gel or foam. In addition, eligible participants had mild to moderate symptoms of skin irritation (a minimum of 10 razor bumps) from shaving based on investigator global severity assessment (IGSA) rating scales and were willing to shave at least 5 times a week during the study period. Participants could continue certain topical and systemic interventions for their skin.

Participants were excluded from the study if they had an underlying inflammatory disease that could manifest with a skin rash or were using any of these medications: topical benzoyl peroxide, topical clindamycin, topical retinoids, or oral antibiotics.

Study Design—A prospective, open-label study was conducted over a period of 12 weeks at a single site in the United States. Investigators instructed participants to shave 5 or more times per week with the test razor and to keep a daily shaving journal to track the number of shaves and compliance.

Participants were evaluated at the baseline screening visit, then at 4, 8, and 12 weeks. Evaluations included an investigator lesion count, the IGSA, and the PGSA. The PGSA was used to evaluate subjective clinical measurements (ie, indicate how much postshave burning/itching/stinging the participant was experiencing). The impact of shaving on daily life was evaluated at the baseline screening visit and at 12 weeks with the Participant Quality of Life Questionnaire comprised of 22 QOL statements. eTable 1 summarizes the investigator assessments used in the study, and eTable 2 summarizes the participant self-assessments. Both tables include the scale details and results interpretation for each assessment.

The study was approved by the local institutional review board, and all participants provided written informed consent in accordance with Title 21 of the Code of Federal Regulations, Part 50.

Study Visits—At the baseline screening visit, participants provided written informed consent and completed a prestudy shave questionnaire concerning shaving preparations, techniques, and opinions. Participants also provided a medical history, including prior and concomitant medications, and were evaluated using the inclusion/exclusion criteria. Investigators explained adverse event reporting to the participants. Participants were provided with an adequate supply of test razors for the 12-week period.

Data Analysis—Means and SDs were calculated for the study measures assessed at each visit. Analyses were performed evaluating change from baseline in repeated-measures analysis of variance models. These models were adjusted for baseline levels of the outcome measure and visit number. The magnitude of change from baseline was evaluated against a null hypothesis of 0% change. This longitudinal model adjusted for any potential differing baseline levels among participants. Statistical significance was defined as P<.05. SAS version 9.4 (SAS Institute Inc) was used for all analyses.

Results

In total, 21 individuals were enrolled, and 20 completed the study. Participants who completed the study were non-Hispanic Black (n=10); non-Hispanic White (n=8); Asian (n=1); or White, American Indian (n=1). All participants adhered to the protocol and reported shaving at least 5 times a week for 12 weeks using the test razor. One participant was removed after he was found to have a history of sarcoidosis, making him ineligible for the study. No study-related adverse events were reported.

Papules and Pustules—Over the course of the 12-week study, the papule count decreased significantly from baseline. Results from the investigator lesion count (see eTable 1 for key) indicated that by week 12—adjusted for number of papules at baseline—the mean percentage reduction was estimated to be 59.6% (P<.0001). A significant decrease in papule count also was observed between the baseline visit and week 8 (57.2%; P<.0001). A nonsignificant decrease was observed at week 4 (18.9%; P=.17). Only 3 participants presented with pustules at baseline, and the pustule count remained low over the course of the study. No significant change was noted at week 12 vs baseline (P=.98). Notably, there was no increase in pustule count at the end of the study compared with baseline (Table 1).

Skin Appearance—An improvement in the skin’s appearance over the course of the study from baseline was consistent with an improvement in the IGSA. The IGSA score significantly improved from a mean (SD) measurement of 2.5 (0.6) (indicating mild to moderate inflammation) at baseline to 1.4 (0.8) at week 8 (P<.0001) and 1.2 (1.1) (indicating mild inflammation to almost clear) at week 12 (P<.0001). The observed decrease in severity of skin condition and skin inflammation is shown in Figure 3.

Significant improvements were observed in every category of the PGSA at week 12 vs baseline (P≤.0007)(Table 2). At week 12, there was a significant (P≤.05) increase from baseline in participant agreement for all 22 QOL metrics describing positive shave experience, achieving results, skin feel, self-confidence, and social interactions (Figure 4), which supports the positive impact of adopting a shaving regimen with the test razor. Notably, after using the test razor for 12 weeks, men reported that they were more likely to agree with the statements “my skin felt smooth,” “my skin felt good to touch,” and “I was able to achieve a consistently good shave.” Other meaningful increases occurred in “shaving was something I looked forward to doing,” “others thought I looked clean cut,” “I looked my best for my family/others/work,” and “I felt comfortable/confident getting closer to others.” All QOL statements are shown in Figure 4.

Improvement With Novel Razor Technology—For the first time, frequent use of a novel razor technology designed specifically for men with PFB was found to significantly improve skin appearance, shave satisfaction, and QOL after 12 weeks vs baseline in participants clinically diagnosed with PFB. In men with shave-related skin irritation and razor bumps who typically wet-shaved with a razor at least 3 times a week, use of the test razor with their regular shaving preparation product 5 or more times per week for 12 weeks was associated with significant improvements from baseline in investigator lesion count, IGSA, PGSA, and Participant Quality of Life Questionnaire measurements.

Study strengths included the quantification of the change in the number of lesions and the degree of severity by a trained investigator in a prospective clinical study along with an assessment of the impact on participant QOL. A lack of a control arm could be considered a limitation of the study; however, study end points were evaluated compared with baseline, with each participant serving as their own control. Spontaneous resolution of the condition with their standard routine was considered highly unlikely in these participants; therefore, in the absence of any other changes, improvements were attributed to regular use of the test product over the course of the study. The results presented here provide strong support for the effectiveness of the new razor technology in improving the appearance of men with razor bumps and shaving irritation.

Hair Removal Tools for the Management of PFB—Although various tools and techniques have been proposed in the past for men with PFB, the current test razor technology provided unique benefits, including improvements in appearance and severity of the condition as well as a positive impact on QOL. In 1979, Conte and Lawrence⁹ evaluated the effect of using an electric hair clipper and twice-daily use of a skin-cleansing pad on the occurrence of PFB. Participants (n=96) allowed their beards to grow out for 1 month, after which they started shaving with an electric clipper with a triple O head. The authors reported a favorable response in 95% (91/96) of cases. However, the electric clippers left 1 mm of beard at the skin level,⁹ which may not be acceptable for those who prefer a clean-shaven appearance.⁶

A prospective survey of 22 men of African descent with PFB found use of a safety razor was preferred over an electric razor.¹⁰ The single-arm study evaluated use of a foil-guarded shaver (single-razor blade) in the management of PFB based on investigator lesion counts and a participant questionnaire. Participants were asked to shave at least every other day and use a specially designed preshave brush. A mean reduction in lesion counts was observed at 2 weeks (29.6%), 4 weeks (38.1%), and 6 weeks (47.1%); statistical significance was not reported. At 6 weeks, 77.3% (17/22) of participants judged the foil-guarded shaver to be superior to other shaving devices in controlling their razor bumps, and 90.9% (20/22) indicated they would recommend the shaver to others with PFB. The authors hypothesized that the guard buffered the skin from the blade, which might otherwise facilitate the penetration of ingrowing hairs and cause trauma to existing lesions.

The mean reduction in lesion count from baseline observed at week 4 was greater in the study with the foil-guarded shaver and preshave brush (38% reduction)¹⁰ than in our study (19% reduction in papule count). Different methodologies, use of a preshave brush in the earlier study, and a difference in lesion severity at baseline may have contributed to this difference. The study with the foil-guarded shaver concluded after 6 weeks, and there was a 47.1% reduction in lesion counts vs baseline.¹⁰ In contrast, the current study continued for 12 weeks, and a 59.6% reduction in lesion counts was reported. Participants from both studies reported an improved shaving experience compared with their usual practice,¹⁰ though only the current study explored the positive impact of the new razor technology on participant QOL.

Preventing Hairs From Being Cut Too Close—The closeness of the shave is believed to be a contributory factor in the development and persistence of PFB^6,8,11 based on a tendency for the distal portion of tightly curled hair shafts to re-enter the skin after shaving via transfollicular penetration.¹² Inclusion of a buffer in the razor between the sharp blades and the skin has been proposed to prevent hairs from being cut too close and causing transfollicular penetration.¹²

In the test razor used in the current study, the bridge technology acted as the buffer to prevent hairs from being cut too close to the skin and to reduce blade contact with the skin (Figure 2). Having only 2 blades also reduced the closeness of the shave compared with 5-bladed technologies,¹³ as each hair can only be pulled and cut up to a maximum of 2 times per shaving stroke. Notably, this did not impact the participants’ QOL scores related to achieving a close shave or skin feeling smooth; both attributes were significantly improved at 12 weeks vs baseline (Figure 4).

By reducing blade contact with the skin, the bridge technology in the test razor was designed to prevent excessive force from being applied to the skin through the blades. Reduced blade loading minimizes contact with and impact on sensitive skin.¹⁴ Additional design features of the test razor to minimize the impact of shaving on the skin include treatment of the 2 blades with low-friction coatings, which allows the blades to cut through the beard hair with minimal force, helping to reduce the tug-and-pull effect that may otherwise result in irritation and inflammation.^13,15 Lubrication strips before and after the blades in the test razor reduce friction between the blades and the skin to further protect the skin from the blades.¹⁵

Shaving With Multiblade Razors Does Not Exacerbate PFB—In a 1-week, split-faced, randomized study of 45 Black men, shaving with a manual 3-bladed razor was compared with use of 3 different chemical depilatory formulations.¹⁶ Shaving every other day for 1 week with the manual razor resulted in more papule formation but less irritation than use of the depilatories. The authors concluded that a study with longer duration was needed to explore the impact of shaving on papule formation in participants with a history of PFB.¹⁶

In 2013, an investigator-blinded study of 90 African American men with PFB compared the impact of different shaving regimens on the signs and symptoms of PFB over a 12-week period.⁴ Participants were randomized to 1 of 3 arms: (1) shaving 2 to 3 times per week with a triple-blade razor and standard products (control group); (2) shaving daily with a 5-bladed razor and standard products; and (3) shaving daily with a 5-bladed razor and “advanced” specific pre- and postshave products. The researchers found that the mean papule measurement significantly decreased from baseline in the advanced (P=.01) and control (P=.016) groups. Between-group comparison revealed no significant differences for papule or pustule count among each arm. For the investigator-graded severity, the change from baseline was significant for all 3 groups (P≤.04); however, the differences among groups were not significant. Importantly, these data demonstrated that PFB was not exacerbated by multiblade razors used as part of a daily shaving regimen.⁴

The findings of the current study were consistent with those of Daniel et al⁴ in that there was no exacerbation of the signs and symptoms of PFB associated with daily shaving. However, rather than requiring participants to change their entire shaving regimen, the present study only required a change of razor type. Moreover, the use of the new razor technology significantly decreased papule counts at week 12 vs the baseline measurement (P<.0001) and was associated with an improvement in subjective skin severity measurements. The participants in the present study reported significantly less burning, stinging, and itching after using the test product for 12 weeks (P<.0001).

Impact of Treatment on QOL—The current study further expanded on prior findings by combining these clinical end points with the QOL results to assess the test razor’s impact on participants’ lives. Results showed that over the course of 12 weeks, the new razor technology significantly improved the participants’ QOL in all questions related to shaving experience, achieving results, skin feel, self-confidence, and social interactions. The significant improvement in QOL included statements such as “shaving was a pleasant experience,” “I was able to achieve a consistently good shave,” and “my skin felt smooth.” Participants also reported improvements in meaningful categories such as “my shave made me feel attractive” and “I felt comfortable/confident getting closer to others.” As the current study showed, a shave regimen has the potential to change participants’ overall assessment of their QOL, a variable that must not be overlooked.

Conclusion

In men with clinically diagnosed PFB, regular shaving with a razor designed to protect the skin was found to significantly decrease lesion counts, increase shave satisfaction, and improve QOL after 12 weeks compared with their usual shaving practice (baseline measures). This razor technology provides another option to help manage PFB for men who wish to or need to continue shaving.

Acknowledgments—The clinical study was funded by the Procter & Gamble Company. Editorial writing assistance, supported financially by the Procter & Gamble Company, was provided by Gill McFeat, PhD, of McFeat Science Ltd (Devon, United Kingdom).

Pseudofolliculitis barbae (PFB)(also known as razor bumps or shaving bumps)¹ is a skin condition that consists of papules resulting from ingrown hairs.² In more severe cases, papules become pustules, then abscesses, which can cause scarring.^1,2 The condition can be distressing for patients, with considerable negative impact on their daily lives.³ The condition also is associated with shaving-related stinging, burning, pruritus, and cuts on the skin.⁴

Pseudofolliculitis barbae is most common in men of African descent due to the curved nature of the hair follicle,^2,5,6 with an estimated prevalence in this population of 45% to 83%,^1,6 but it can affect men of other ethnicities.⁷ A genetic polymorphism in a gene encoding a keratin specific to the hair follicle also has been found to predispose some individuals to PFB.⁵ When hair from a curved or destabilized hair follicle is cut to form a sharp tip, it is susceptible to extrafollicular and/or transfollicular penetration,^5,6,8 as illustrated in Figure 1.

With extrafollicular or transfollicular penetration, the hair shaft re-enters or retracts into the dermis, triggering an inflammatory response that may be exacerbated by subsequent shaving.² Few studies have been published that aim to identify potential shaving solutions for individuals with PFB who elect to or need to continue shaving.

A new razor technology comprising 2 blades separated by a bridge feature has been designed specifically for men with razor bumps (SkinGuard [Procter & Gamble]). The SkinGuard razor redistributes shaving pressure so that there is less force from the blades on the skin and inflamed lesions than without the bridge, as seen in Figure 2. The razor has been designed to protect the skin from the blades, thereby minimizing the occurrence of new lesions and allowing existing lesions to heal.

The primary purpose of this study was to assess the appearance of males with razor bumps and shaving irritation when using the new razor technology in a regular shaving routine. The secondary objective was to measure satisfaction of the shaving experience when using the new razor by means of assessing itching, burning, and stinging using the participant global severity assessment (PGSA) and the impact on quality of life (QOL) measures.

Methods

Participants—Eligible participants were male, aged 20 to 60 years, and had clinically diagnosed PFB as well as symptoms of skin irritation from shaving. Participants were recruited from a dermatology clinic and via institutional review board–approved advertising.

Those eligible for inclusion in the study had a shaving routine that comprised shaving at least 3 times a week using a wet-shave, blade-razor technique accompanied by only a shave gel or foam. In addition, eligible participants had mild to moderate symptoms of skin irritation (a minimum of 10 razor bumps) from shaving based on investigator global severity assessment (IGSA) rating scales and were willing to shave at least 5 times a week during the study period. Participants could continue certain topical and systemic interventions for their skin.

Participants were excluded from the study if they had an underlying inflammatory disease that could manifest with a skin rash or were using any of these medications: topical benzoyl peroxide, topical clindamycin, topical retinoids, or oral antibiotics.

Study Design—A prospective, open-label study was conducted over a period of 12 weeks at a single site in the United States. Investigators instructed participants to shave 5 or more times per week with the test razor and to keep a daily shaving journal to track the number of shaves and compliance.

Participants were evaluated at the baseline screening visit, then at 4, 8, and 12 weeks. Evaluations included an investigator lesion count, the IGSA, and the PGSA. The PGSA was used to evaluate subjective clinical measurements (ie, indicate how much postshave burning/itching/stinging the participant was experiencing). The impact of shaving on daily life was evaluated at the baseline screening visit and at 12 weeks with the Participant Quality of Life Questionnaire comprised of 22 QOL statements. eTable 1 summarizes the investigator assessments used in the study, and eTable 2 summarizes the participant self-assessments. Both tables include the scale details and results interpretation for each assessment.

The study was approved by the local institutional review board, and all participants provided written informed consent in accordance with Title 21 of the Code of Federal Regulations, Part 50.

Study Visits—At the baseline screening visit, participants provided written informed consent and completed a prestudy shave questionnaire concerning shaving preparations, techniques, and opinions. Participants also provided a medical history, including prior and concomitant medications, and were evaluated using the inclusion/exclusion criteria. Investigators explained adverse event reporting to the participants. Participants were provided with an adequate supply of test razors for the 12-week period.

Data Analysis—Means and SDs were calculated for the study measures assessed at each visit. Analyses were performed evaluating change from baseline in repeated-measures analysis of variance models. These models were adjusted for baseline levels of the outcome measure and visit number. The magnitude of change from baseline was evaluated against a null hypothesis of 0% change. This longitudinal model adjusted for any potential differing baseline levels among participants. Statistical significance was defined as P<.05. SAS version 9.4 (SAS Institute Inc) was used for all analyses.

Results

In total, 21 individuals were enrolled, and 20 completed the study. Participants who completed the study were non-Hispanic Black (n=10); non-Hispanic White (n=8); Asian (n=1); or White, American Indian (n=1). All participants adhered to the protocol and reported shaving at least 5 times a week for 12 weeks using the test razor. One participant was removed after he was found to have a history of sarcoidosis, making him ineligible for the study. No study-related adverse events were reported.

Papules and Pustules—Over the course of the 12-week study, the papule count decreased significantly from baseline. Results from the investigator lesion count (see eTable 1 for key) indicated that by week 12—adjusted for number of papules at baseline—the mean percentage reduction was estimated to be 59.6% (P<.0001). A significant decrease in papule count also was observed between the baseline visit and week 8 (57.2%; P<.0001). A nonsignificant decrease was observed at week 4 (18.9%; P=.17). Only 3 participants presented with pustules at baseline, and the pustule count remained low over the course of the study. No significant change was noted at week 12 vs baseline (P=.98). Notably, there was no increase in pustule count at the end of the study compared with baseline (Table 1).

Skin Appearance—An improvement in the skin’s appearance over the course of the study from baseline was consistent with an improvement in the IGSA. The IGSA score significantly improved from a mean (SD) measurement of 2.5 (0.6) (indicating mild to moderate inflammation) at baseline to 1.4 (0.8) at week 8 (P<.0001) and 1.2 (1.1) (indicating mild inflammation to almost clear) at week 12 (P<.0001). The observed decrease in severity of skin condition and skin inflammation is shown in Figure 3.

Significant improvements were observed in every category of the PGSA at week 12 vs baseline (P≤.0007)(Table 2). At week 12, there was a significant (P≤.05) increase from baseline in participant agreement for all 22 QOL metrics describing positive shave experience, achieving results, skin feel, self-confidence, and social interactions (Figure 4), which supports the positive impact of adopting a shaving regimen with the test razor. Notably, after using the test razor for 12 weeks, men reported that they were more likely to agree with the statements “my skin felt smooth,” “my skin felt good to touch,” and “I was able to achieve a consistently good shave.” Other meaningful increases occurred in “shaving was something I looked forward to doing,” “others thought I looked clean cut,” “I looked my best for my family/others/work,” and “I felt comfortable/confident getting closer to others.” All QOL statements are shown in Figure 4.

Improvement With Novel Razor Technology—For the first time, frequent use of a novel razor technology designed specifically for men with PFB was found to significantly improve skin appearance, shave satisfaction, and QOL after 12 weeks vs baseline in participants clinically diagnosed with PFB. In men with shave-related skin irritation and razor bumps who typically wet-shaved with a razor at least 3 times a week, use of the test razor with their regular shaving preparation product 5 or more times per week for 12 weeks was associated with significant improvements from baseline in investigator lesion count, IGSA, PGSA, and Participant Quality of Life Questionnaire measurements.

Study strengths included the quantification of the change in the number of lesions and the degree of severity by a trained investigator in a prospective clinical study along with an assessment of the impact on participant QOL. A lack of a control arm could be considered a limitation of the study; however, study end points were evaluated compared with baseline, with each participant serving as their own control. Spontaneous resolution of the condition with their standard routine was considered highly unlikely in these participants; therefore, in the absence of any other changes, improvements were attributed to regular use of the test product over the course of the study. The results presented here provide strong support for the effectiveness of the new razor technology in improving the appearance of men with razor bumps and shaving irritation.

Hair Removal Tools for the Management of PFB—Although various tools and techniques have been proposed in the past for men with PFB, the current test razor technology provided unique benefits, including improvements in appearance and severity of the condition as well as a positive impact on QOL. In 1979, Conte and Lawrence⁹ evaluated the effect of using an electric hair clipper and twice-daily use of a skin-cleansing pad on the occurrence of PFB. Participants (n=96) allowed their beards to grow out for 1 month, after which they started shaving with an electric clipper with a triple O head. The authors reported a favorable response in 95% (91/96) of cases. However, the electric clippers left 1 mm of beard at the skin level,⁹ which may not be acceptable for those who prefer a clean-shaven appearance.⁶

A prospective survey of 22 men of African descent with PFB found use of a safety razor was preferred over an electric razor.¹⁰ The single-arm study evaluated use of a foil-guarded shaver (single-razor blade) in the management of PFB based on investigator lesion counts and a participant questionnaire. Participants were asked to shave at least every other day and use a specially designed preshave brush. A mean reduction in lesion counts was observed at 2 weeks (29.6%), 4 weeks (38.1%), and 6 weeks (47.1%); statistical significance was not reported. At 6 weeks, 77.3% (17/22) of participants judged the foil-guarded shaver to be superior to other shaving devices in controlling their razor bumps, and 90.9% (20/22) indicated they would recommend the shaver to others with PFB. The authors hypothesized that the guard buffered the skin from the blade, which might otherwise facilitate the penetration of ingrowing hairs and cause trauma to existing lesions.

The mean reduction in lesion count from baseline observed at week 4 was greater in the study with the foil-guarded shaver and preshave brush (38% reduction)¹⁰ than in our study (19% reduction in papule count). Different methodologies, use of a preshave brush in the earlier study, and a difference in lesion severity at baseline may have contributed to this difference. The study with the foil-guarded shaver concluded after 6 weeks, and there was a 47.1% reduction in lesion counts vs baseline.¹⁰ In contrast, the current study continued for 12 weeks, and a 59.6% reduction in lesion counts was reported. Participants from both studies reported an improved shaving experience compared with their usual practice,¹⁰ though only the current study explored the positive impact of the new razor technology on participant QOL.

Preventing Hairs From Being Cut Too Close—The closeness of the shave is believed to be a contributory factor in the development and persistence of PFB^6,8,11 based on a tendency for the distal portion of tightly curled hair shafts to re-enter the skin after shaving via transfollicular penetration.¹² Inclusion of a buffer in the razor between the sharp blades and the skin has been proposed to prevent hairs from being cut too close and causing transfollicular penetration.¹²

In the test razor used in the current study, the bridge technology acted as the buffer to prevent hairs from being cut too close to the skin and to reduce blade contact with the skin (Figure 2). Having only 2 blades also reduced the closeness of the shave compared with 5-bladed technologies,¹³ as each hair can only be pulled and cut up to a maximum of 2 times per shaving stroke. Notably, this did not impact the participants’ QOL scores related to achieving a close shave or skin feeling smooth; both attributes were significantly improved at 12 weeks vs baseline (Figure 4).

By reducing blade contact with the skin, the bridge technology in the test razor was designed to prevent excessive force from being applied to the skin through the blades. Reduced blade loading minimizes contact with and impact on sensitive skin.¹⁴ Additional design features of the test razor to minimize the impact of shaving on the skin include treatment of the 2 blades with low-friction coatings, which allows the blades to cut through the beard hair with minimal force, helping to reduce the tug-and-pull effect that may otherwise result in irritation and inflammation.^13,15 Lubrication strips before and after the blades in the test razor reduce friction between the blades and the skin to further protect the skin from the blades.¹⁵

Shaving With Multiblade Razors Does Not Exacerbate PFB—In a 1-week, split-faced, randomized study of 45 Black men, shaving with a manual 3-bladed razor was compared with use of 3 different chemical depilatory formulations.¹⁶ Shaving every other day for 1 week with the manual razor resulted in more papule formation but less irritation than use of the depilatories. The authors concluded that a study with longer duration was needed to explore the impact of shaving on papule formation in participants with a history of PFB.¹⁶

In 2013, an investigator-blinded study of 90 African American men with PFB compared the impact of different shaving regimens on the signs and symptoms of PFB over a 12-week period.⁴ Participants were randomized to 1 of 3 arms: (1) shaving 2 to 3 times per week with a triple-blade razor and standard products (control group); (2) shaving daily with a 5-bladed razor and standard products; and (3) shaving daily with a 5-bladed razor and “advanced” specific pre- and postshave products. The researchers found that the mean papule measurement significantly decreased from baseline in the advanced (P=.01) and control (P=.016) groups. Between-group comparison revealed no significant differences for papule or pustule count among each arm. For the investigator-graded severity, the change from baseline was significant for all 3 groups (P≤.04); however, the differences among groups were not significant. Importantly, these data demonstrated that PFB was not exacerbated by multiblade razors used as part of a daily shaving regimen.⁴

The findings of the current study were consistent with those of Daniel et al⁴ in that there was no exacerbation of the signs and symptoms of PFB associated with daily shaving. However, rather than requiring participants to change their entire shaving regimen, the present study only required a change of razor type. Moreover, the use of the new razor technology significantly decreased papule counts at week 12 vs the baseline measurement (P<.0001) and was associated with an improvement in subjective skin severity measurements. The participants in the present study reported significantly less burning, stinging, and itching after using the test product for 12 weeks (P<.0001).

Impact of Treatment on QOL—The current study further expanded on prior findings by combining these clinical end points with the QOL results to assess the test razor’s impact on participants’ lives. Results showed that over the course of 12 weeks, the new razor technology significantly improved the participants’ QOL in all questions related to shaving experience, achieving results, skin feel, self-confidence, and social interactions. The significant improvement in QOL included statements such as “shaving was a pleasant experience,” “I was able to achieve a consistently good shave,” and “my skin felt smooth.” Participants also reported improvements in meaningful categories such as “my shave made me feel attractive” and “I felt comfortable/confident getting closer to others.” As the current study showed, a shave regimen has the potential to change participants’ overall assessment of their QOL, a variable that must not be overlooked.

Conclusion

In men with clinically diagnosed PFB, regular shaving with a razor designed to protect the skin was found to significantly decrease lesion counts, increase shave satisfaction, and improve QOL after 12 weeks compared with their usual shaving practice (baseline measures). This razor technology provides another option to help manage PFB for men who wish to or need to continue shaving.

Acknowledgments—The clinical study was funded by the Procter & Gamble Company. Editorial writing assistance, supported financially by the Procter & Gamble Company, was provided by Gill McFeat, PhD, of McFeat Science Ltd (Devon, United Kingdom).

Pseudofolliculitis barbae (PFB)(also known as razor bumps or shaving bumps)¹ is a skin condition that consists of papules resulting from ingrown hairs.² In more severe cases, papules become pustules, then abscesses, which can cause scarring.^1,2 The condition can be distressing for patients, with considerable negative impact on their daily lives.³ The condition also is associated with shaving-related stinging, burning, pruritus, and cuts on the skin.⁴

Pseudofolliculitis barbae is most common in men of African descent due to the curved nature of the hair follicle,^2,5,6 with an estimated prevalence in this population of 45% to 83%,^1,6 but it can affect men of other ethnicities.⁷ A genetic polymorphism in a gene encoding a keratin specific to the hair follicle also has been found to predispose some individuals to PFB.⁵ When hair from a curved or destabilized hair follicle is cut to form a sharp tip, it is susceptible to extrafollicular and/or transfollicular penetration,^5,6,8 as illustrated in Figure 1.

With extrafollicular or transfollicular penetration, the hair shaft re-enters or retracts into the dermis, triggering an inflammatory response that may be exacerbated by subsequent shaving.² Few studies have been published that aim to identify potential shaving solutions for individuals with PFB who elect to or need to continue shaving.

A new razor technology comprising 2 blades separated by a bridge feature has been designed specifically for men with razor bumps (SkinGuard [Procter & Gamble]). The SkinGuard razor redistributes shaving pressure so that there is less force from the blades on the skin and inflamed lesions than without the bridge, as seen in Figure 2. The razor has been designed to protect the skin from the blades, thereby minimizing the occurrence of new lesions and allowing existing lesions to heal.

The primary purpose of this study was to assess the appearance of males with razor bumps and shaving irritation when using the new razor technology in a regular shaving routine. The secondary objective was to measure satisfaction of the shaving experience when using the new razor by means of assessing itching, burning, and stinging using the participant global severity assessment (PGSA) and the impact on quality of life (QOL) measures.

Methods

Participants—Eligible participants were male, aged 20 to 60 years, and had clinically diagnosed PFB as well as symptoms of skin irritation from shaving. Participants were recruited from a dermatology clinic and via institutional review board–approved advertising.

Those eligible for inclusion in the study had a shaving routine that comprised shaving at least 3 times a week using a wet-shave, blade-razor technique accompanied by only a shave gel or foam. In addition, eligible participants had mild to moderate symptoms of skin irritation (a minimum of 10 razor bumps) from shaving based on investigator global severity assessment (IGSA) rating scales and were willing to shave at least 5 times a week during the study period. Participants could continue certain topical and systemic interventions for their skin.

Participants were excluded from the study if they had an underlying inflammatory disease that could manifest with a skin rash or were using any of these medications: topical benzoyl peroxide, topical clindamycin, topical retinoids, or oral antibiotics.

Study Design—A prospective, open-label study was conducted over a period of 12 weeks at a single site in the United States. Investigators instructed participants to shave 5 or more times per week with the test razor and to keep a daily shaving journal to track the number of shaves and compliance.

Participants were evaluated at the baseline screening visit, then at 4, 8, and 12 weeks. Evaluations included an investigator lesion count, the IGSA, and the PGSA. The PGSA was used to evaluate subjective clinical measurements (ie, indicate how much postshave burning/itching/stinging the participant was experiencing). The impact of shaving on daily life was evaluated at the baseline screening visit and at 12 weeks with the Participant Quality of Life Questionnaire comprised of 22 QOL statements. eTable 1 summarizes the investigator assessments used in the study, and eTable 2 summarizes the participant self-assessments. Both tables include the scale details and results interpretation for each assessment.

The study was approved by the local institutional review board, and all participants provided written informed consent in accordance with Title 21 of the Code of Federal Regulations, Part 50.

Study Visits—At the baseline screening visit, participants provided written informed consent and completed a prestudy shave questionnaire concerning shaving preparations, techniques, and opinions. Participants also provided a medical history, including prior and concomitant medications, and were evaluated using the inclusion/exclusion criteria. Investigators explained adverse event reporting to the participants. Participants were provided with an adequate supply of test razors for the 12-week period.

Data Analysis—Means and SDs were calculated for the study measures assessed at each visit. Analyses were performed evaluating change from baseline in repeated-measures analysis of variance models. These models were adjusted for baseline levels of the outcome measure and visit number. The magnitude of change from baseline was evaluated against a null hypothesis of 0% change. This longitudinal model adjusted for any potential differing baseline levels among participants. Statistical significance was defined as P<.05. SAS version 9.4 (SAS Institute Inc) was used for all analyses.

Results

In total, 21 individuals were enrolled, and 20 completed the study. Participants who completed the study were non-Hispanic Black (n=10); non-Hispanic White (n=8); Asian (n=1); or White, American Indian (n=1). All participants adhered to the protocol and reported shaving at least 5 times a week for 12 weeks using the test razor. One participant was removed after he was found to have a history of sarcoidosis, making him ineligible for the study. No study-related adverse events were reported.

Papules and Pustules—Over the course of the 12-week study, the papule count decreased significantly from baseline. Results from the investigator lesion count (see eTable 1 for key) indicated that by week 12—adjusted for number of papules at baseline—the mean percentage reduction was estimated to be 59.6% (P<.0001). A significant decrease in papule count also was observed between the baseline visit and week 8 (57.2%; P<.0001). A nonsignificant decrease was observed at week 4 (18.9%; P=.17). Only 3 participants presented with pustules at baseline, and the pustule count remained low over the course of the study. No significant change was noted at week 12 vs baseline (P=.98). Notably, there was no increase in pustule count at the end of the study compared with baseline (Table 1).

Skin Appearance—An improvement in the skin’s appearance over the course of the study from baseline was consistent with an improvement in the IGSA. The IGSA score significantly improved from a mean (SD) measurement of 2.5 (0.6) (indicating mild to moderate inflammation) at baseline to 1.4 (0.8) at week 8 (P<.0001) and 1.2 (1.1) (indicating mild inflammation to almost clear) at week 12 (P<.0001). The observed decrease in severity of skin condition and skin inflammation is shown in Figure 3.

Significant improvements were observed in every category of the PGSA at week 12 vs baseline (P≤.0007)(Table 2). At week 12, there was a significant (P≤.05) increase from baseline in participant agreement for all 22 QOL metrics describing positive shave experience, achieving results, skin feel, self-confidence, and social interactions (Figure 4), which supports the positive impact of adopting a shaving regimen with the test razor. Notably, after using the test razor for 12 weeks, men reported that they were more likely to agree with the statements “my skin felt smooth,” “my skin felt good to touch,” and “I was able to achieve a consistently good shave.” Other meaningful increases occurred in “shaving was something I looked forward to doing,” “others thought I looked clean cut,” “I looked my best for my family/others/work,” and “I felt comfortable/confident getting closer to others.” All QOL statements are shown in Figure 4.

Improvement With Novel Razor Technology—For the first time, frequent use of a novel razor technology designed specifically for men with PFB was found to significantly improve skin appearance, shave satisfaction, and QOL after 12 weeks vs baseline in participants clinically diagnosed with PFB. In men with shave-related skin irritation and razor bumps who typically wet-shaved with a razor at least 3 times a week, use of the test razor with their regular shaving preparation product 5 or more times per week for 12 weeks was associated with significant improvements from baseline in investigator lesion count, IGSA, PGSA, and Participant Quality of Life Questionnaire measurements.

Study strengths included the quantification of the change in the number of lesions and the degree of severity by a trained investigator in a prospective clinical study along with an assessment of the impact on participant QOL. A lack of a control arm could be considered a limitation of the study; however, study end points were evaluated compared with baseline, with each participant serving as their own control. Spontaneous resolution of the condition with their standard routine was considered highly unlikely in these participants; therefore, in the absence of any other changes, improvements were attributed to regular use of the test product over the course of the study. The results presented here provide strong support for the effectiveness of the new razor technology in improving the appearance of men with razor bumps and shaving irritation.

Hair Removal Tools for the Management of PFB—Although various tools and techniques have been proposed in the past for men with PFB, the current test razor technology provided unique benefits, including improvements in appearance and severity of the condition as well as a positive impact on QOL. In 1979, Conte and Lawrence⁹ evaluated the effect of using an electric hair clipper and twice-daily use of a skin-cleansing pad on the occurrence of PFB. Participants (n=96) allowed their beards to grow out for 1 month, after which they started shaving with an electric clipper with a triple O head. The authors reported a favorable response in 95% (91/96) of cases. However, the electric clippers left 1 mm of beard at the skin level,⁹ which may not be acceptable for those who prefer a clean-shaven appearance.⁶

A prospective survey of 22 men of African descent with PFB found use of a safety razor was preferred over an electric razor.¹⁰ The single-arm study evaluated use of a foil-guarded shaver (single-razor blade) in the management of PFB based on investigator lesion counts and a participant questionnaire. Participants were asked to shave at least every other day and use a specially designed preshave brush. A mean reduction in lesion counts was observed at 2 weeks (29.6%), 4 weeks (38.1%), and 6 weeks (47.1%); statistical significance was not reported. At 6 weeks, 77.3% (17/22) of participants judged the foil-guarded shaver to be superior to other shaving devices in controlling their razor bumps, and 90.9% (20/22) indicated they would recommend the shaver to others with PFB. The authors hypothesized that the guard buffered the skin from the blade, which might otherwise facilitate the penetration of ingrowing hairs and cause trauma to existing lesions.

The mean reduction in lesion count from baseline observed at week 4 was greater in the study with the foil-guarded shaver and preshave brush (38% reduction)¹⁰ than in our study (19% reduction in papule count). Different methodologies, use of a preshave brush in the earlier study, and a difference in lesion severity at baseline may have contributed to this difference. The study with the foil-guarded shaver concluded after 6 weeks, and there was a 47.1% reduction in lesion counts vs baseline.¹⁰ In contrast, the current study continued for 12 weeks, and a 59.6% reduction in lesion counts was reported. Participants from both studies reported an improved shaving experience compared with their usual practice,¹⁰ though only the current study explored the positive impact of the new razor technology on participant QOL.

Preventing Hairs From Being Cut Too Close—The closeness of the shave is believed to be a contributory factor in the development and persistence of PFB^6,8,11 based on a tendency for the distal portion of tightly curled hair shafts to re-enter the skin after shaving via transfollicular penetration.¹² Inclusion of a buffer in the razor between the sharp blades and the skin has been proposed to prevent hairs from being cut too close and causing transfollicular penetration.¹²

In the test razor used in the current study, the bridge technology acted as the buffer to prevent hairs from being cut too close to the skin and to reduce blade contact with the skin (Figure 2). Having only 2 blades also reduced the closeness of the shave compared with 5-bladed technologies,¹³ as each hair can only be pulled and cut up to a maximum of 2 times per shaving stroke. Notably, this did not impact the participants’ QOL scores related to achieving a close shave or skin feeling smooth; both attributes were significantly improved at 12 weeks vs baseline (Figure 4).

By reducing blade contact with the skin, the bridge technology in the test razor was designed to prevent excessive force from being applied to the skin through the blades. Reduced blade loading minimizes contact with and impact on sensitive skin.¹⁴ Additional design features of the test razor to minimize the impact of shaving on the skin include treatment of the 2 blades with low-friction coatings, which allows the blades to cut through the beard hair with minimal force, helping to reduce the tug-and-pull effect that may otherwise result in irritation and inflammation.^13,15 Lubrication strips before and after the blades in the test razor reduce friction between the blades and the skin to further protect the skin from the blades.¹⁵

Shaving With Multiblade Razors Does Not Exacerbate PFB—In a 1-week, split-faced, randomized study of 45 Black men, shaving with a manual 3-bladed razor was compared with use of 3 different chemical depilatory formulations.¹⁶ Shaving every other day for 1 week with the manual razor resulted in more papule formation but less irritation than use of the depilatories. The authors concluded that a study with longer duration was needed to explore the impact of shaving on papule formation in participants with a history of PFB.¹⁶

In 2013, an investigator-blinded study of 90 African American men with PFB compared the impact of different shaving regimens on the signs and symptoms of PFB over a 12-week period.⁴ Participants were randomized to 1 of 3 arms: (1) shaving 2 to 3 times per week with a triple-blade razor and standard products (control group); (2) shaving daily with a 5-bladed razor and standard products; and (3) shaving daily with a 5-bladed razor and “advanced” specific pre- and postshave products. The researchers found that the mean papule measurement significantly decreased from baseline in the advanced (P=.01) and control (P=.016) groups. Between-group comparison revealed no significant differences for papule or pustule count among each arm. For the investigator-graded severity, the change from baseline was significant for all 3 groups (P≤.04); however, the differences among groups were not significant. Importantly, these data demonstrated that PFB was not exacerbated by multiblade razors used as part of a daily shaving regimen.⁴

The findings of the current study were consistent with those of Daniel et al⁴ in that there was no exacerbation of the signs and symptoms of PFB associated with daily shaving. However, rather than requiring participants to change their entire shaving regimen, the present study only required a change of razor type. Moreover, the use of the new razor technology significantly decreased papule counts at week 12 vs the baseline measurement (P<.0001) and was associated with an improvement in subjective skin severity measurements. The participants in the present study reported significantly less burning, stinging, and itching after using the test product for 12 weeks (P<.0001).

Impact of Treatment on QOL—The current study further expanded on prior findings by combining these clinical end points with the QOL results to assess the test razor’s impact on participants’ lives. Results showed that over the course of 12 weeks, the new razor technology significantly improved the participants’ QOL in all questions related to shaving experience, achieving results, skin feel, self-confidence, and social interactions. The significant improvement in QOL included statements such as “shaving was a pleasant experience,” “I was able to achieve a consistently good shave,” and “my skin felt smooth.” Participants also reported improvements in meaningful categories such as “my shave made me feel attractive” and “I felt comfortable/confident getting closer to others.” As the current study showed, a shave regimen has the potential to change participants’ overall assessment of their QOL, a variable that must not be overlooked.

Conclusion

In men with clinically diagnosed PFB, regular shaving with a razor designed to protect the skin was found to significantly decrease lesion counts, increase shave satisfaction, and improve QOL after 12 weeks compared with their usual shaving practice (baseline measures). This razor technology provides another option to help manage PFB for men who wish to or need to continue shaving.

Acknowledgments—The clinical study was funded by the Procter & Gamble Company. Editorial writing assistance, supported financially by the Procter & Gamble Company, was provided by Gill McFeat, PhD, of McFeat Science Ltd (Devon, United Kingdom).

The Diagnosis: Mid-Borderline Multibacillary Leprosy

The biopsies showed a granulomatous dermatitis involving the dermis and subcutaneous adipose tissue (Figure, A). Fite staining also revealed numerous acid-fast bacilli (AFB) throughout the dermis (Figure, B); however, polymerase chain reaction (PCR) for Mycobacterium tuberculosis was negative, and concomitant AFB tissue culture showed no growth after 8 weeks of incubation from the left wrist biopsy (Table). Interestingly, a left inguinal lymph node biopsy performed 6 months prior to presentation that helped to establish the diagnosis of follicular lymphoma also revealed nonnecrotizing granulomas and the presence of rare AFB; this formalin-fixed specimen subsequently tested negative for M tuberculosis and nontuberculous mycobacteria (NTM) by broad-range PCR. Due to a high index of suspicion, another unpreserved skin biopsy of the right knee was sent for NTM testing with PCR. Primers to 16S ribosomal RNA and the beta subunit of RNA polymerase, rpoB, gene detected Mycobacterium leprae DNA, leading to the diagnosis of mid-borderline (or borderline-borderline) multibacillary leprosy. Our patient subsequently reported subtle hypoesthesia of the plaques on the knees. He recalled eating undercooked armadillo meat in the southern United States more than 30 years prior to admission. In addition, he had a history of being incarcerated in the northeastern United States. This case was reported to the National Hansen’s Disease Program, and our patient was started on a 2-year course of daily clarithromycin, daily minocycline, and once-monthly moxifloxacin. His family also was evaluated and did not have any skin lesions concerning for leprosy.

Leprosy is a major global health concern, transmitted via breaks in the skin, respiratory secretions, and contact with armadillos. It continues to be endemic in India, Brazil, and Indonesia.¹ In the United States where leprosy is nonendemic, 159 new cases were detected in 2020; the most notable risk factors in the United States are armadillo exposure and travel history.^2,3Mycobacterium leprae are intracellular bacilli that preferentially infect macrophages and Schwann cells, resulting in erythematous or hypopigmented skin lesions that often are anesthetic. Mycobacterium leprae has the longest doubling time of all bacteria with unknown in vitro growth requirements and a typical in vivo incubation period of 2 to 10 years.⁴ Therefore, in vitro cultures will yield no growth, as seen in our case. In our patient, Fite stain showed acid-fast organisms in multiple tissue specimens, but AFB cultures demonstrated no growth after 8 weeks of incubation. Although clinicopathologic correlation is most important, PCR analysis can help to assist in the diagnosis of leprosy. Unpreserved tissue should be used when possible, as the fixation process may adversely affect the analytic sensitivity of subsequent PCR-based assays.⁵ In our case, NTM were not detected by PCR in the inguinal lymph node specimen despite demonstrating rare AFB staining. This result likely was multifactorial, including the effect of formalin fixation and paraffin embedding as well as concomitant low biomass.

Leprosy is known as a great imitator, and clinical manifestations (both neurologic and cutaneous) depend on host immune response to the mycobacteria. Although tuberculoid leprosy (associated with T helper type 1 immune response) is distinguished by few asymmetric, well-demarcated, and often hypopigmented plaques, lepromatous leprosy (associated with T helper type 2 response) is characterized by numerous symmetric and poorly defined lesions. Borderline leprosy, as seen in our patient, is the most common type of leprosy and shows features of both tuberculoid and lepromatous leprosy.⁴ It also may be particularly difficult to diagnose.^6,7 Borderline-borderline leprosy involves lesions that mostly are of the lepromatous type and symmetric but also may include raised plaques, as in tuberculoid leprosy.⁴ Plaques in an annular configuration with central clearing, as seen in our patient, are considered suggestive.⁸ Histopathology of borderline-borderline leprosy lesions shows subepidermal clear zones, and granulomas are more diffuse than in tuberculoid leprosy.⁴

Given the noncaseating granulomatous dermatitis seen on histopathology and the relatively higher incidence of sarcoidosis in our region of practice, our initial differential included sarcoidosis and other granulomatous disorders such as granuloma annulare. Interestingly, sarcoidosis has been misdiagnosed as leprosy on multiple occasions in countries where leprosy is endemic.^9,10 Localized cutaneous leishmaniasis typically presents with infiltrated plaques and nodules that may ulcerate; diffuse and disseminated as well as mucocutaneous presentations may occur depending on the species and severity of infection. Parasitized macrophages containing amastigotes may be seen in the dermis highlighted by CD1a immunostaining. Mycosis fungoides presents as papulosquamous patches or plaques, often favoring sunprotected sites; the hypopigmented variant may mimic the central clearing seen in leprosy.

The diagnosis of leprosy can be challenging due to varying clinical presentation; indolent growth of the causative organism; and indeterminate nature of stains, including the Fite stain. Although leprosy is an uncommon diagnosis, this case underscores the need to keep it in the differential of granulomatous dermatoses in the appropriate clinical setting, particularly in patients with risk factors for exposure.⁸

The Diagnosis: Mid-Borderline Multibacillary Leprosy

The biopsies showed a granulomatous dermatitis involving the dermis and subcutaneous adipose tissue (Figure, A). Fite staining also revealed numerous acid-fast bacilli (AFB) throughout the dermis (Figure, B); however, polymerase chain reaction (PCR) for Mycobacterium tuberculosis was negative, and concomitant AFB tissue culture showed no growth after 8 weeks of incubation from the left wrist biopsy (Table). Interestingly, a left inguinal lymph node biopsy performed 6 months prior to presentation that helped to establish the diagnosis of follicular lymphoma also revealed nonnecrotizing granulomas and the presence of rare AFB; this formalin-fixed specimen subsequently tested negative for M tuberculosis and nontuberculous mycobacteria (NTM) by broad-range PCR. Due to a high index of suspicion, another unpreserved skin biopsy of the right knee was sent for NTM testing with PCR. Primers to 16S ribosomal RNA and the beta subunit of RNA polymerase, rpoB, gene detected Mycobacterium leprae DNA, leading to the diagnosis of mid-borderline (or borderline-borderline) multibacillary leprosy. Our patient subsequently reported subtle hypoesthesia of the plaques on the knees. He recalled eating undercooked armadillo meat in the southern United States more than 30 years prior to admission. In addition, he had a history of being incarcerated in the northeastern United States. This case was reported to the National Hansen’s Disease Program, and our patient was started on a 2-year course of daily clarithromycin, daily minocycline, and once-monthly moxifloxacin. His family also was evaluated and did not have any skin lesions concerning for leprosy.

Leprosy is a major global health concern, transmitted via breaks in the skin, respiratory secretions, and contact with armadillos. It continues to be endemic in India, Brazil, and Indonesia.¹ In the United States where leprosy is nonendemic, 159 new cases were detected in 2020; the most notable risk factors in the United States are armadillo exposure and travel history.^2,3Mycobacterium leprae are intracellular bacilli that preferentially infect macrophages and Schwann cells, resulting in erythematous or hypopigmented skin lesions that often are anesthetic. Mycobacterium leprae has the longest doubling time of all bacteria with unknown in vitro growth requirements and a typical in vivo incubation period of 2 to 10 years.⁴ Therefore, in vitro cultures will yield no growth, as seen in our case. In our patient, Fite stain showed acid-fast organisms in multiple tissue specimens, but AFB cultures demonstrated no growth after 8 weeks of incubation. Although clinicopathologic correlation is most important, PCR analysis can help to assist in the diagnosis of leprosy. Unpreserved tissue should be used when possible, as the fixation process may adversely affect the analytic sensitivity of subsequent PCR-based assays.⁵ In our case, NTM were not detected by PCR in the inguinal lymph node specimen despite demonstrating rare AFB staining. This result likely was multifactorial, including the effect of formalin fixation and paraffin embedding as well as concomitant low biomass.

Leprosy is known as a great imitator, and clinical manifestations (both neurologic and cutaneous) depend on host immune response to the mycobacteria. Although tuberculoid leprosy (associated with T helper type 1 immune response) is distinguished by few asymmetric, well-demarcated, and often hypopigmented plaques, lepromatous leprosy (associated with T helper type 2 response) is characterized by numerous symmetric and poorly defined lesions. Borderline leprosy, as seen in our patient, is the most common type of leprosy and shows features of both tuberculoid and lepromatous leprosy.⁴ It also may be particularly difficult to diagnose.^6,7 Borderline-borderline leprosy involves lesions that mostly are of the lepromatous type and symmetric but also may include raised plaques, as in tuberculoid leprosy.⁴ Plaques in an annular configuration with central clearing, as seen in our patient, are considered suggestive.⁸ Histopathology of borderline-borderline leprosy lesions shows subepidermal clear zones, and granulomas are more diffuse than in tuberculoid leprosy.⁴

Given the noncaseating granulomatous dermatitis seen on histopathology and the relatively higher incidence of sarcoidosis in our region of practice, our initial differential included sarcoidosis and other granulomatous disorders such as granuloma annulare. Interestingly, sarcoidosis has been misdiagnosed as leprosy on multiple occasions in countries where leprosy is endemic.^9,10 Localized cutaneous leishmaniasis typically presents with infiltrated plaques and nodules that may ulcerate; diffuse and disseminated as well as mucocutaneous presentations may occur depending on the species and severity of infection. Parasitized macrophages containing amastigotes may be seen in the dermis highlighted by CD1a immunostaining. Mycosis fungoides presents as papulosquamous patches or plaques, often favoring sunprotected sites; the hypopigmented variant may mimic the central clearing seen in leprosy.

The diagnosis of leprosy can be challenging due to varying clinical presentation; indolent growth of the causative organism; and indeterminate nature of stains, including the Fite stain. Although leprosy is an uncommon diagnosis, this case underscores the need to keep it in the differential of granulomatous dermatoses in the appropriate clinical setting, particularly in patients with risk factors for exposure.⁸

The Diagnosis: Mid-Borderline Multibacillary Leprosy

The biopsies showed a granulomatous dermatitis involving the dermis and subcutaneous adipose tissue (Figure, A). Fite staining also revealed numerous acid-fast bacilli (AFB) throughout the dermis (Figure, B); however, polymerase chain reaction (PCR) for Mycobacterium tuberculosis was negative, and concomitant AFB tissue culture showed no growth after 8 weeks of incubation from the left wrist biopsy (Table). Interestingly, a left inguinal lymph node biopsy performed 6 months prior to presentation that helped to establish the diagnosis of follicular lymphoma also revealed nonnecrotizing granulomas and the presence of rare AFB; this formalin-fixed specimen subsequently tested negative for M tuberculosis and nontuberculous mycobacteria (NTM) by broad-range PCR. Due to a high index of suspicion, another unpreserved skin biopsy of the right knee was sent for NTM testing with PCR. Primers to 16S ribosomal RNA and the beta subunit of RNA polymerase, rpoB, gene detected Mycobacterium leprae DNA, leading to the diagnosis of mid-borderline (or borderline-borderline) multibacillary leprosy. Our patient subsequently reported subtle hypoesthesia of the plaques on the knees. He recalled eating undercooked armadillo meat in the southern United States more than 30 years prior to admission. In addition, he had a history of being incarcerated in the northeastern United States. This case was reported to the National Hansen’s Disease Program, and our patient was started on a 2-year course of daily clarithromycin, daily minocycline, and once-monthly moxifloxacin. His family also was evaluated and did not have any skin lesions concerning for leprosy.

Leprosy is a major global health concern, transmitted via breaks in the skin, respiratory secretions, and contact with armadillos. It continues to be endemic in India, Brazil, and Indonesia.¹ In the United States where leprosy is nonendemic, 159 new cases were detected in 2020; the most notable risk factors in the United States are armadillo exposure and travel history.^2,3Mycobacterium leprae are intracellular bacilli that preferentially infect macrophages and Schwann cells, resulting in erythematous or hypopigmented skin lesions that often are anesthetic. Mycobacterium leprae has the longest doubling time of all bacteria with unknown in vitro growth requirements and a typical in vivo incubation period of 2 to 10 years.⁴ Therefore, in vitro cultures will yield no growth, as seen in our case. In our patient, Fite stain showed acid-fast organisms in multiple tissue specimens, but AFB cultures demonstrated no growth after 8 weeks of incubation. Although clinicopathologic correlation is most important, PCR analysis can help to assist in the diagnosis of leprosy. Unpreserved tissue should be used when possible, as the fixation process may adversely affect the analytic sensitivity of subsequent PCR-based assays.⁵ In our case, NTM were not detected by PCR in the inguinal lymph node specimen despite demonstrating rare AFB staining. This result likely was multifactorial, including the effect of formalin fixation and paraffin embedding as well as concomitant low biomass.

Leprosy is known as a great imitator, and clinical manifestations (both neurologic and cutaneous) depend on host immune response to the mycobacteria. Although tuberculoid leprosy (associated with T helper type 1 immune response) is distinguished by few asymmetric, well-demarcated, and often hypopigmented plaques, lepromatous leprosy (associated with T helper type 2 response) is characterized by numerous symmetric and poorly defined lesions. Borderline leprosy, as seen in our patient, is the most common type of leprosy and shows features of both tuberculoid and lepromatous leprosy.⁴ It also may be particularly difficult to diagnose.^6,7 Borderline-borderline leprosy involves lesions that mostly are of the lepromatous type and symmetric but also may include raised plaques, as in tuberculoid leprosy.⁴ Plaques in an annular configuration with central clearing, as seen in our patient, are considered suggestive.⁸ Histopathology of borderline-borderline leprosy lesions shows subepidermal clear zones, and granulomas are more diffuse than in tuberculoid leprosy.⁴

Given the noncaseating granulomatous dermatitis seen on histopathology and the relatively higher incidence of sarcoidosis in our region of practice, our initial differential included sarcoidosis and other granulomatous disorders such as granuloma annulare. Interestingly, sarcoidosis has been misdiagnosed as leprosy on multiple occasions in countries where leprosy is endemic.^9,10 Localized cutaneous leishmaniasis typically presents with infiltrated plaques and nodules that may ulcerate; diffuse and disseminated as well as mucocutaneous presentations may occur depending on the species and severity of infection. Parasitized macrophages containing amastigotes may be seen in the dermis highlighted by CD1a immunostaining. Mycosis fungoides presents as papulosquamous patches or plaques, often favoring sunprotected sites; the hypopigmented variant may mimic the central clearing seen in leprosy.

The diagnosis of leprosy can be challenging due to varying clinical presentation; indolent growth of the causative organism; and indeterminate nature of stains, including the Fite stain. Although leprosy is an uncommon diagnosis, this case underscores the need to keep it in the differential of granulomatous dermatoses in the appropriate clinical setting, particularly in patients with risk factors for exposure.⁸

Change is inevitable in residency as well as in life. Every year on July 1, the atmosphere and social structure of residencies change with the new postgraduate year 2 class. Each class brings a unique perspective and energy. Residents come together from different backgrounds and life situations. Some residents are single, some are engaged or married, and some are starting or expanding their families. Some residents will have prior careers, others will have graduate degrees or expertise in various fields. They will have different ethnic backgrounds, religious and/or spiritual beliefs, familial upbringings, personalities, and methods of communicating. These differences all are important to consider when developing a mindset of inclusion and camaraderie. As residents start their journey together, it is important to remember that residency is a team endeavor. The principles of teamwork apply directly to residents and are founded on creating a climate of trust and building strong relationships with one another._¹ Trust is the foundation of good relationships in the workplace; it allows people to communicate freely and foster the belief that everyone is working for each other’s best interests. Being open and sharing knowledge about networking opportunities, scholarships, and research projects is one way to foster collaboration and trust in residency.

Diversity, equity, and inclusion in dermatology is a work in progress. In the 2020-2021 dermatology application cycle, only 4.8% of applicants identified as Hispanic or Latino, and 7.8% identified as Black or African American.² The American Academy of Dermatology took an active role in promoting diversity by creating a task force in 2018 to increase the exposure and recruitment into dermatology of medical students who are underrepresented in medicine.2 As standards for diversity are met in dermatology, we will have the wonderful opportunity to welcome even more diversity into our lives.

Listening, showing curiosity about your co-residents’ lives outside of work, and asking questions can help build respect, friendships, and camaraderie. Ask your co-residents what makes them happy and what their goals are in residency. Finding common goals and cultivating the mindset that you all work together to achieve your goals is key to the success of a residency class. Now that we discussed accepting and welcoming differences, how do you foster camaraderie in a social setting?

Establish a Social Committee

As a class, consider 1 or 2 residents who are always excited to try new activities such as attend restaurant openings, exercise classes, concerts, or movie nights. Consider nominating these co-residents along with one attending to be social chairs of your residency. The social chairs should meet and establish at least 1 social event per season, with 4 total for the academic year. There are only 2 rules with social events: (1) they must be held outside of clinic, and (2) everyone should try their best to attend.

Social chairs should try to prioritize a location-specific event that allows the residents who are not from the area to experience something local, which can be anything from apple picking at an orchard in the fall to beach volleyball in the summer. Planning these parties gives everyone an event to look forward to and a chance to spend time together and grow closer. The memories and inside jokes that arise from these outings are invaluable and increase joy inside and outside of clinic.

Utilize Social Media

Another project can be developing a social media account for your program with the approval of your faculty. @unmcdermatology, @uwderm, and @gwdermres can help foster social relationships by establishing a lighthearted space to celebrate the residency’s achievements, new publications, volunteer events, or social gatherings.

Encourage Local and National Conference Attendance

All residents should be encouraged to submit abstracts to local and national conferences and attend with their co-residents. Conferences are peak opportunities to foster camaraderie within residency classes, as they involve a sense of togetherness in the specialty along with the excitement of traveling to a new city and meeting other like-minded individuals. Conferences allow collaboration within the specialty on a national level and foster relationships between residency programs.

In addition, national groups such as the Women’s Dermatologic Society, the Skin of Color Society, and the American Academy of Dermatology Diversity, Equity, and Inclusion task force meet at the national conferences and discuss their next initiatives and projects. Joining a society of your interest can lead to many new networks and relationships you may not have had before. Even if you are not interested in specializing after general dermatology, consider attending a surgery, dermatopathology, or pediatric or cosmetic dermatology conference to learn more about the field from the experts.

Repair Conflicts and Build a Climate of Collaboration

Conflicts and disagreements unfortunately are inevitable during residency. Whether they involve planning vacation times or coordinating call schedules, everyone will not agree on every decision. Learning how to handle and approach conflict with co-residents is of utmost importance to maintaining the hard work you have put in to create trust, camaraderie, and a good social atmosphere. If you are having an issue with a circumstance involving a co-resident, holding a grudge will only sour your experience and the experience of others. Talking to your co-resident directly about your concerns before escalating the issue to a chief resident or faculty member is a great start. Consider asking them about their thought process and show concern for their point of view. Listen to them openly before going into your preferences. It is important to remember that working as a team requires sacrifices, and sometimes you will not be satisfied with the outcome of a conflict.

It also is important to remember that feelings change, and an issue you feel you must address immediately can wait to be addressed at a better time when you have calmed down. You may even find that you decide not to address it at all. At the end of the day, if a conflict cannot be worked out between those involved, consider confiding in a chief resident or a faculty mentor for advice on the next steps to take to resolve the problem. Ultimately, having a good foundation of respect and strong bonds with your residents will help tremendously when conflicts arise.

Final Thoughts

Fostering camaraderie in residency will improve the overall experience and lives of the residents, as well as the experience of the faculty, staff, and patients by the trickle-down effect. Creating a cheerful and fun atmosphere filled with inside jokes and excitement regarding upcoming social events or conferences will certainly result in a time you will cherish for the rest of your life.

Change is inevitable in residency as well as in life. Every year on July 1, the atmosphere and social structure of residencies change with the new postgraduate year 2 class. Each class brings a unique perspective and energy. Residents come together from different backgrounds and life situations. Some residents are single, some are engaged or married, and some are starting or expanding their families. Some residents will have prior careers, others will have graduate degrees or expertise in various fields. They will have different ethnic backgrounds, religious and/or spiritual beliefs, familial upbringings, personalities, and methods of communicating. These differences all are important to consider when developing a mindset of inclusion and camaraderie. As residents start their journey together, it is important to remember that residency is a team endeavor. The principles of teamwork apply directly to residents and are founded on creating a climate of trust and building strong relationships with one another._¹ Trust is the foundation of good relationships in the workplace; it allows people to communicate freely and foster the belief that everyone is working for each other’s best interests. Being open and sharing knowledge about networking opportunities, scholarships, and research projects is one way to foster collaboration and trust in residency.

Diversity, equity, and inclusion in dermatology is a work in progress. In the 2020-2021 dermatology application cycle, only 4.8% of applicants identified as Hispanic or Latino, and 7.8% identified as Black or African American.² The American Academy of Dermatology took an active role in promoting diversity by creating a task force in 2018 to increase the exposure and recruitment into dermatology of medical students who are underrepresented in medicine.2 As standards for diversity are met in dermatology, we will have the wonderful opportunity to welcome even more diversity into our lives.

Listening, showing curiosity about your co-residents’ lives outside of work, and asking questions can help build respect, friendships, and camaraderie. Ask your co-residents what makes them happy and what their goals are in residency. Finding common goals and cultivating the mindset that you all work together to achieve your goals is key to the success of a residency class. Now that we discussed accepting and welcoming differences, how do you foster camaraderie in a social setting?

Establish a Social Committee

As a class, consider 1 or 2 residents who are always excited to try new activities such as attend restaurant openings, exercise classes, concerts, or movie nights. Consider nominating these co-residents along with one attending to be social chairs of your residency. The social chairs should meet and establish at least 1 social event per season, with 4 total for the academic year. There are only 2 rules with social events: (1) they must be held outside of clinic, and (2) everyone should try their best to attend.

Social chairs should try to prioritize a location-specific event that allows the residents who are not from the area to experience something local, which can be anything from apple picking at an orchard in the fall to beach volleyball in the summer. Planning these parties gives everyone an event to look forward to and a chance to spend time together and grow closer. The memories and inside jokes that arise from these outings are invaluable and increase joy inside and outside of clinic.

Utilize Social Media

Another project can be developing a social media account for your program with the approval of your faculty. @unmcdermatology, @uwderm, and @gwdermres can help foster social relationships by establishing a lighthearted space to celebrate the residency’s achievements, new publications, volunteer events, or social gatherings.

Encourage Local and National Conference Attendance

All residents should be encouraged to submit abstracts to local and national conferences and attend with their co-residents. Conferences are peak opportunities to foster camaraderie within residency classes, as they involve a sense of togetherness in the specialty along with the excitement of traveling to a new city and meeting other like-minded individuals. Conferences allow collaboration within the specialty on a national level and foster relationships between residency programs.

In addition, national groups such as the Women’s Dermatologic Society, the Skin of Color Society, and the American Academy of Dermatology Diversity, Equity, and Inclusion task force meet at the national conferences and discuss their next initiatives and projects. Joining a society of your interest can lead to many new networks and relationships you may not have had before. Even if you are not interested in specializing after general dermatology, consider attending a surgery, dermatopathology, or pediatric or cosmetic dermatology conference to learn more about the field from the experts.

Repair Conflicts and Build a Climate of Collaboration

Conflicts and disagreements unfortunately are inevitable during residency. Whether they involve planning vacation times or coordinating call schedules, everyone will not agree on every decision. Learning how to handle and approach conflict with co-residents is of utmost importance to maintaining the hard work you have put in to create trust, camaraderie, and a good social atmosphere. If you are having an issue with a circumstance involving a co-resident, holding a grudge will only sour your experience and the experience of others. Talking to your co-resident directly about your concerns before escalating the issue to a chief resident or faculty member is a great start. Consider asking them about their thought process and show concern for their point of view. Listen to them openly before going into your preferences. It is important to remember that working as a team requires sacrifices, and sometimes you will not be satisfied with the outcome of a conflict.

It also is important to remember that feelings change, and an issue you feel you must address immediately can wait to be addressed at a better time when you have calmed down. You may even find that you decide not to address it at all. At the end of the day, if a conflict cannot be worked out between those involved, consider confiding in a chief resident or a faculty mentor for advice on the next steps to take to resolve the problem. Ultimately, having a good foundation of respect and strong bonds with your residents will help tremendously when conflicts arise.

Final Thoughts

Fostering camaraderie in residency will improve the overall experience and lives of the residents, as well as the experience of the faculty, staff, and patients by the trickle-down effect. Creating a cheerful and fun atmosphere filled with inside jokes and excitement regarding upcoming social events or conferences will certainly result in a time you will cherish for the rest of your life.

Change is inevitable in residency as well as in life. Every year on July 1, the atmosphere and social structure of residencies change with the new postgraduate year 2 class. Each class brings a unique perspective and energy. Residents come together from different backgrounds and life situations. Some residents are single, some are engaged or married, and some are starting or expanding their families. Some residents will have prior careers, others will have graduate degrees or expertise in various fields. They will have different ethnic backgrounds, religious and/or spiritual beliefs, familial upbringings, personalities, and methods of communicating. These differences all are important to consider when developing a mindset of inclusion and camaraderie. As residents start their journey together, it is important to remember that residency is a team endeavor. The principles of teamwork apply directly to residents and are founded on creating a climate of trust and building strong relationships with one another._¹ Trust is the foundation of good relationships in the workplace; it allows people to communicate freely and foster the belief that everyone is working for each other’s best interests. Being open and sharing knowledge about networking opportunities, scholarships, and research projects is one way to foster collaboration and trust in residency.

Diversity, equity, and inclusion in dermatology is a work in progress. In the 2020-2021 dermatology application cycle, only 4.8% of applicants identified as Hispanic or Latino, and 7.8% identified as Black or African American.² The American Academy of Dermatology took an active role in promoting diversity by creating a task force in 2018 to increase the exposure and recruitment into dermatology of medical students who are underrepresented in medicine.2 As standards for diversity are met in dermatology, we will have the wonderful opportunity to welcome even more diversity into our lives.

Listening, showing curiosity about your co-residents’ lives outside of work, and asking questions can help build respect, friendships, and camaraderie. Ask your co-residents what makes them happy and what their goals are in residency. Finding common goals and cultivating the mindset that you all work together to achieve your goals is key to the success of a residency class. Now that we discussed accepting and welcoming differences, how do you foster camaraderie in a social setting?

Establish a Social Committee

As a class, consider 1 or 2 residents who are always excited to try new activities such as attend restaurant openings, exercise classes, concerts, or movie nights. Consider nominating these co-residents along with one attending to be social chairs of your residency. The social chairs should meet and establish at least 1 social event per season, with 4 total for the academic year. There are only 2 rules with social events: (1) they must be held outside of clinic, and (2) everyone should try their best to attend.

Social chairs should try to prioritize a location-specific event that allows the residents who are not from the area to experience something local, which can be anything from apple picking at an orchard in the fall to beach volleyball in the summer. Planning these parties gives everyone an event to look forward to and a chance to spend time together and grow closer. The memories and inside jokes that arise from these outings are invaluable and increase joy inside and outside of clinic.

Utilize Social Media

Another project can be developing a social media account for your program with the approval of your faculty. @unmcdermatology, @uwderm, and @gwdermres can help foster social relationships by establishing a lighthearted space to celebrate the residency’s achievements, new publications, volunteer events, or social gatherings.

Encourage Local and National Conference Attendance

All residents should be encouraged to submit abstracts to local and national conferences and attend with their co-residents. Conferences are peak opportunities to foster camaraderie within residency classes, as they involve a sense of togetherness in the specialty along with the excitement of traveling to a new city and meeting other like-minded individuals. Conferences allow collaboration within the specialty on a national level and foster relationships between residency programs.

In addition, national groups such as the Women’s Dermatologic Society, the Skin of Color Society, and the American Academy of Dermatology Diversity, Equity, and Inclusion task force meet at the national conferences and discuss their next initiatives and projects. Joining a society of your interest can lead to many new networks and relationships you may not have had before. Even if you are not interested in specializing after general dermatology, consider attending a surgery, dermatopathology, or pediatric or cosmetic dermatology conference to learn more about the field from the experts.

Repair Conflicts and Build a Climate of Collaboration

Conflicts and disagreements unfortunately are inevitable during residency. Whether they involve planning vacation times or coordinating call schedules, everyone will not agree on every decision. Learning how to handle and approach conflict with co-residents is of utmost importance to maintaining the hard work you have put in to create trust, camaraderie, and a good social atmosphere. If you are having an issue with a circumstance involving a co-resident, holding a grudge will only sour your experience and the experience of others. Talking to your co-resident directly about your concerns before escalating the issue to a chief resident or faculty member is a great start. Consider asking them about their thought process and show concern for their point of view. Listen to them openly before going into your preferences. It is important to remember that working as a team requires sacrifices, and sometimes you will not be satisfied with the outcome of a conflict.

It also is important to remember that feelings change, and an issue you feel you must address immediately can wait to be addressed at a better time when you have calmed down. You may even find that you decide not to address it at all. At the end of the day, if a conflict cannot be worked out between those involved, consider confiding in a chief resident or a faculty mentor for advice on the next steps to take to resolve the problem. Ultimately, having a good foundation of respect and strong bonds with your residents will help tremendously when conflicts arise.

Final Thoughts

Fostering camaraderie in residency will improve the overall experience and lives of the residents, as well as the experience of the faculty, staff, and patients by the trickle-down effect. Creating a cheerful and fun atmosphere filled with inside jokes and excitement regarding upcoming social events or conferences will certainly result in a time you will cherish for the rest of your life.

The Diagnosis: Solitary Sclerotic Fibroma

Based on the clinical and histologic findings, the patient was diagnosed with solitary sclerotic fibroma (SF). Sclerotic fibroma is a rare benign tumor that first was described in 1972 by Weary et al¹ in the oral mucosa of a patient with Cowden syndrome, a genodermatosis associated with multiple benign and malignant tumors. Rapini and Golitz² reported solitary SF in 11 otherwise-healthy individuals with no signs of multiple hamartoma syndrome. Solitary SF is a sporadic benign condition, whereas multiple lesions are suggestive of Cowden syndrome. Solitary SF most commonly appears as an asymptomatic white-yellow papule or nodule on the head or neck, though larger tumors have been reported on the trunk and extremities.³ Histologic features of solitary SF include a well-circumscribed dermal nodule composed of eosinophilic dense collagen bundles arranged in a plywoodlike pattern (Figure). Immunohistochemistry is positive for CD34 and vimentin but negative for S-100, epithelial membrane antigen, and neuron-specific enolase.⁴

The differential diagnosis of solitary SF of the head and neck includes sebaceous adenoma, pilar cyst, nodular basal cell carcinoma, and giant molluscum contagiosum. Sebaceous adenomas usually are solitary yellow nodules less than 1 cm in diameter and located on the head and neck. They are the most common sebaceous neoplasm associated with Muir-Torre syndrome, an autosomal-dominant disorder characterized by sebaceous adenoma or carcinoma and colorectal cancer. Histopathology demonstrates well-circumscribed, round aggregations of mature lipid-filled sebocytes with a rim of basaloid germinative cells at the periphery. Pilar cysts typically are flesh-colored subcutaneous nodules on the scalp that are freely mobile over underlying tissue. Histopathology shows stratified squamous epithelium lining and trichilemmal keratinization. Nodular basal cell carcinoma has a pearly translucent appearance and arborizing telangiectases. Histopathology demonstrates nests of basaloid cells with palisading of the cells at the periphery. Giant solitary molluscum contagiosum is a dome-shaped, flesh-colored nodule with central umbilication. Histopathology reveals hyperplastic squamous epithelium with characteristic eosinophilic inclusion bodies above the basal layer.

Solitary SF can be difficult to diagnose based solely on the clinical presentation; thus biopsy with histologic evaluation is recommended. If SF is confirmed, the clinician should inquire about a family history of Cowden syndrome and then perform a total-body skin examination to check for multiple SF and other clinical hamartomas of Cowden syndrome such as trichilemmomas, acral keratosis, and oral papillomas.

The Diagnosis: Solitary Sclerotic Fibroma

Based on the clinical and histologic findings, the patient was diagnosed with solitary sclerotic fibroma (SF). Sclerotic fibroma is a rare benign tumor that first was described in 1972 by Weary et al¹ in the oral mucosa of a patient with Cowden syndrome, a genodermatosis associated with multiple benign and malignant tumors. Rapini and Golitz² reported solitary SF in 11 otherwise-healthy individuals with no signs of multiple hamartoma syndrome. Solitary SF is a sporadic benign condition, whereas multiple lesions are suggestive of Cowden syndrome. Solitary SF most commonly appears as an asymptomatic white-yellow papule or nodule on the head or neck, though larger tumors have been reported on the trunk and extremities.³ Histologic features of solitary SF include a well-circumscribed dermal nodule composed of eosinophilic dense collagen bundles arranged in a plywoodlike pattern (Figure). Immunohistochemistry is positive for CD34 and vimentin but negative for S-100, epithelial membrane antigen, and neuron-specific enolase.⁴

The differential diagnosis of solitary SF of the head and neck includes sebaceous adenoma, pilar cyst, nodular basal cell carcinoma, and giant molluscum contagiosum. Sebaceous adenomas usually are solitary yellow nodules less than 1 cm in diameter and located on the head and neck. They are the most common sebaceous neoplasm associated with Muir-Torre syndrome, an autosomal-dominant disorder characterized by sebaceous adenoma or carcinoma and colorectal cancer. Histopathology demonstrates well-circumscribed, round aggregations of mature lipid-filled sebocytes with a rim of basaloid germinative cells at the periphery. Pilar cysts typically are flesh-colored subcutaneous nodules on the scalp that are freely mobile over underlying tissue. Histopathology shows stratified squamous epithelium lining and trichilemmal keratinization. Nodular basal cell carcinoma has a pearly translucent appearance and arborizing telangiectases. Histopathology demonstrates nests of basaloid cells with palisading of the cells at the periphery. Giant solitary molluscum contagiosum is a dome-shaped, flesh-colored nodule with central umbilication. Histopathology reveals hyperplastic squamous epithelium with characteristic eosinophilic inclusion bodies above the basal layer.

Solitary SF can be difficult to diagnose based solely on the clinical presentation; thus biopsy with histologic evaluation is recommended. If SF is confirmed, the clinician should inquire about a family history of Cowden syndrome and then perform a total-body skin examination to check for multiple SF and other clinical hamartomas of Cowden syndrome such as trichilemmomas, acral keratosis, and oral papillomas.

The Diagnosis: Solitary Sclerotic Fibroma

Based on the clinical and histologic findings, the patient was diagnosed with solitary sclerotic fibroma (SF). Sclerotic fibroma is a rare benign tumor that first was described in 1972 by Weary et al¹ in the oral mucosa of a patient with Cowden syndrome, a genodermatosis associated with multiple benign and malignant tumors. Rapini and Golitz² reported solitary SF in 11 otherwise-healthy individuals with no signs of multiple hamartoma syndrome. Solitary SF is a sporadic benign condition, whereas multiple lesions are suggestive of Cowden syndrome. Solitary SF most commonly appears as an asymptomatic white-yellow papule or nodule on the head or neck, though larger tumors have been reported on the trunk and extremities.³ Histologic features of solitary SF include a well-circumscribed dermal nodule composed of eosinophilic dense collagen bundles arranged in a plywoodlike pattern (Figure). Immunohistochemistry is positive for CD34 and vimentin but negative for S-100, epithelial membrane antigen, and neuron-specific enolase.⁴

The differential diagnosis of solitary SF of the head and neck includes sebaceous adenoma, pilar cyst, nodular basal cell carcinoma, and giant molluscum contagiosum. Sebaceous adenomas usually are solitary yellow nodules less than 1 cm in diameter and located on the head and neck. They are the most common sebaceous neoplasm associated with Muir-Torre syndrome, an autosomal-dominant disorder characterized by sebaceous adenoma or carcinoma and colorectal cancer. Histopathology demonstrates well-circumscribed, round aggregations of mature lipid-filled sebocytes with a rim of basaloid germinative cells at the periphery. Pilar cysts typically are flesh-colored subcutaneous nodules on the scalp that are freely mobile over underlying tissue. Histopathology shows stratified squamous epithelium lining and trichilemmal keratinization. Nodular basal cell carcinoma has a pearly translucent appearance and arborizing telangiectases. Histopathology demonstrates nests of basaloid cells with palisading of the cells at the periphery. Giant solitary molluscum contagiosum is a dome-shaped, flesh-colored nodule with central umbilication. Histopathology reveals hyperplastic squamous epithelium with characteristic eosinophilic inclusion bodies above the basal layer.

Solitary SF can be difficult to diagnose based solely on the clinical presentation; thus biopsy with histologic evaluation is recommended. If SF is confirmed, the clinician should inquire about a family history of Cowden syndrome and then perform a total-body skin examination to check for multiple SF and other clinical hamartomas of Cowden syndrome such as trichilemmomas, acral keratosis, and oral papillomas.

To the Editor:

An 82-year-old man presented to our dermatology clinic for a total-body skin examination due to a recently diagnosed primary melanoma of the left middle ear. He reported pain of the left ear and water behind the left eardrum of 1 year’s duration. An otorhinolaryngologist performed surgery due to the severe mastoiditis. A biopsy of the contents of the left middle ear revealed malignant melanoma. Positron emission tomography–computed tomography revealed the mass was mainly located in the anterior aspect of the left middle ear with suspicion of tumor extension into the bony portion of the eustachian tube. No other disease was present. Prior to presentation to dermatology, gross excision of the left middle ear with removal of additional melanoma was confirmed by biopsy, and further analysis revealed v-Raf murine sarcoma viral oncogene (BRAF) was not detected while cellular proto-oncogene receptor kinase (KIT) mutation was detected on exon 13p (K642E).

The patient had no family history of melanoma. He never smoked and did not have contact with hazardous material. Initial examination at our clinic revealed no other suspicious pigmented lesions. After additional negative workup by the oncologist, the patient was presented to the tumor board, and postoperative radiotherapy was recommended to improve local control. Eight months after the patient’s initial diagnosis of the primary middle ear melanoma, a computed tomography–guided right lung biopsy showed metastatic melanoma. After various treatment modalities were discussed with the patient and his family, he was started on pembrolizumab. After 6 months on pembrolizumab, the patient developed autoimmune pneumonitis and pembrolizumab was discontinued. The patient elected to discontinue treatment and died 6 months later.

Malignant melanoma with primary involvement of the middle ear and mastoid mucosa rarely has been reported.^1-3 Primary malignant melanoma of the middle ear mucosa is difficult to diagnose clinically. Difficulty and delay in diagnosis occur because of the location and frequent lack of pathognomonic symptoms of the disease.² A comprehensive literature review by Maxwell et al³ in 2018 of the 10 reported primary middle ear mucosal melanomas found that patients most commonly presented with otorrhea, aural fullness, and hearing loss. Less common symptoms included otalgia, tinnitus, and facial weakness. Clinical examination revealed patients presented with serous otitis and/or a visible mass within the middle ear or external auditory canal. These melanomas demonstrated particularly poor outcomes, with 70% mortality, 20% local recurrence, and 50% distant metastasis. Distant metastases that occurred with primary middle ear mucosal melanoma include lung, liver, intraparotid, abdomen, and cutaneous metastasis.³

The specific pathophysiologic factors underlying the development of primary malignant melanoma of the middle ear mucosa are not known.² The middle ear and its components develop from the first and second pharyngeal arches.⁴ Melanocyte precursors from the neural crest migrate during the seventh or eighth week of embryogenesis. These precursors migrate to the epidermis, various mucosal epithelial, hair follicles, dermis, retina, uveal tract, leptomeninges, inner ear, and other tissues.⁵ The ossicles of the middle ear develop from the neural crest⁶ and remain in the mesenchyme until the eighth month, when the surrounding tissue dissolves.⁴ Cutaneous melanomas arise from the malignant transformation of melanocytes in the skin of neural crest lineage. Noncutaneous melanomas are hypothesized to arise from melanoblasts migrating to noncutaneous organs after neural crest cells undergo an epithelial-mesenchymal translation.⁷

Melanoma 5-year survival rates vary based on the melanoma disease stage: 98% for stage 1, 90% for stage 2, 70% for stage 3, and 10% for stage 4. Although early-stage disease mainly is treated with surgery, advanced and unresectable disease is managed with different therapeutic options, including BRAF inhibitors such as vemurafenib, dabrafenib mesylate, and encorafenib; immune checkpoint inhibitors such as ipilimumab, nivolumab, and pembrolizumab; and oncolytic virus such as talimogene laherparepvec.^8,9

Ninety percent of melanomas are of cutaneous origin. Extracutaneous melanomas may be derived from the uvea, leptomeninges, mucous membranes, and gastrointestinal tract.¹⁰ Mucosal melanomas are rare and represent only approximately 1% of all melanomas.¹¹ In order of frequency, primary mucosal melanomas include the head and neck, anorectal region, vulvovaginal region, and urinary tract. UV radiation exposure is an important risk factor for cutaneous melanoma but has not been associated with the development of mucosal melanoma.⁷ In 2019, Altieri et al¹¹ analyzed 1824 cases of mucosal melanoma and found that anatomic site influences survival because mucosal melanomas in the most occult anatomic sites—spinal/central nervous system, lung and pleura, liver, and pancreas—have the worst prognosis, likely because they have already metastasized by the time they are diagnosed. Due to their occult anatomic location and lack of early presenting signs and symptoms, mucosal melanomas are difficult to diagnose at an early stage, resulting in a poorer prognosis compared with cutaneous melanomas. The most important prognostic indicator for cutaneous melanomas of tumor thickness (ie, Breslow depth) provides less prognostic value for patients with mucosal melanoma. Limitations also include the lack of a standardized staging system for mucosal melanoma, but Altieri et al¹¹ found that poorer survival in patients with mucosal melanoma was observed in relation to stage based on the clinical and pathologic tumor-node-metastasis staging system of the Surveillance, Epidemiology, and End Results program. An aggregate 5-year survival estimate of patients diagnosed with mucosal melanoma is 28%, underscoring that mucosal melanoma is an aggressive melanoma that carries a poor prognosis and warrants a more aggressive treatment approach at the time of diagnosis.¹¹

Common treatment of primary middle ear mucosal melanoma involves a multimodality therapy including surgical oncological resection for most patients. Currently, radiation is in use for adjuvant treatment and definitive therapy in unresectable tumors or patients who are poor surgical candidates. Malignant melanoma traditionally was considered radioresistant, yet considerable variability in responsiveness has been observed both within and between tumors. Although there are no defined indications for adjuvant therapy, it is often administered in advanced or recurrent cases and those with positive or close margins. Chemotherapy generally is reserved for patients with systemic disease. The chemotherapeutic agents that have been used in the treatment of patients with melanoma of the middle ear include the alkylating agents dacarbazine, cisplatin, nimustine, paclitaxel, and temozolomide. Also, chemotherapeutic agents that have been reported in the treatment of melanoma of the middle ear include tamoxifen, the selective estrogen receptor inhibitor, and interferon. Most recently, programed cell death protein 1 inhibitors pembrolizumab and nivolumab have been used in the treatment of middle ear melanoma. Outcomes remain poor with a high rate of mortality. Novel immunotherapeutic agents combined with adjuvant radiotherapy have been proposed to improve disease control and survival rates.³

Data on systemic therapies for mucosal melanomas are limited due to the rarity of the disease. Even with the development of novel therapies, outcomes remain poor for mucosal melanomas, and additional treatment strategies are needed. Although proto-oncogene BRAF mutations occur in 50% to 70% of cutaneous melanomas, these mutations are rare in mucosal melanomas.³ In mucosal melanomas, activating mutations of the cell receptor KIT are identified more frequently.⁷ Alterations in proto-oncogene KIT have been found in acral, mucosal, and cutaneous melanoma. KIT mutations were found on exons 11 and 13.¹² Variability in the biology of KIT is suggested. Treatment of melanomas with the KIT mutations with tyrosine inhibitors imatinib and nilotinib have shown variable benefits.¹⁰ In a 2019 study of 44 patients with mucosal melanoma, Moya-Plana et al¹³ found that in cases of unresectable and/or metastatic disease, immunotherapy with pembrolizumab had a better benefit-risk ratio than immune treatment with ipilimumab, a cytotoxic T-cell lymphocyte-associated protein 4 inhibitor.

Primary malignant melanoma of the middle ear is unusual and difficult to diagnose clinically. These melanomas have a poor prognosis and can have distant metastasis including cutaneous metastasis. We present this case to emphasize the need to be aware that melanoma can arise in the middle ear.

To the Editor:

An 82-year-old man presented to our dermatology clinic for a total-body skin examination due to a recently diagnosed primary melanoma of the left middle ear. He reported pain of the left ear and water behind the left eardrum of 1 year’s duration. An otorhinolaryngologist performed surgery due to the severe mastoiditis. A biopsy of the contents of the left middle ear revealed malignant melanoma. Positron emission tomography–computed tomography revealed the mass was mainly located in the anterior aspect of the left middle ear with suspicion of tumor extension into the bony portion of the eustachian tube. No other disease was present. Prior to presentation to dermatology, gross excision of the left middle ear with removal of additional melanoma was confirmed by biopsy, and further analysis revealed v-Raf murine sarcoma viral oncogene (BRAF) was not detected while cellular proto-oncogene receptor kinase (KIT) mutation was detected on exon 13p (K642E).

The patient had no family history of melanoma. He never smoked and did not have contact with hazardous material. Initial examination at our clinic revealed no other suspicious pigmented lesions. After additional negative workup by the oncologist, the patient was presented to the tumor board, and postoperative radiotherapy was recommended to improve local control. Eight months after the patient’s initial diagnosis of the primary middle ear melanoma, a computed tomography–guided right lung biopsy showed metastatic melanoma. After various treatment modalities were discussed with the patient and his family, he was started on pembrolizumab. After 6 months on pembrolizumab, the patient developed autoimmune pneumonitis and pembrolizumab was discontinued. The patient elected to discontinue treatment and died 6 months later.

Malignant melanoma with primary involvement of the middle ear and mastoid mucosa rarely has been reported.^1-3 Primary malignant melanoma of the middle ear mucosa is difficult to diagnose clinically. Difficulty and delay in diagnosis occur because of the location and frequent lack of pathognomonic symptoms of the disease.² A comprehensive literature review by Maxwell et al³ in 2018 of the 10 reported primary middle ear mucosal melanomas found that patients most commonly presented with otorrhea, aural fullness, and hearing loss. Less common symptoms included otalgia, tinnitus, and facial weakness. Clinical examination revealed patients presented with serous otitis and/or a visible mass within the middle ear or external auditory canal. These melanomas demonstrated particularly poor outcomes, with 70% mortality, 20% local recurrence, and 50% distant metastasis. Distant metastases that occurred with primary middle ear mucosal melanoma include lung, liver, intraparotid, abdomen, and cutaneous metastasis.³

The specific pathophysiologic factors underlying the development of primary malignant melanoma of the middle ear mucosa are not known.² The middle ear and its components develop from the first and second pharyngeal arches.⁴ Melanocyte precursors from the neural crest migrate during the seventh or eighth week of embryogenesis. These precursors migrate to the epidermis, various mucosal epithelial, hair follicles, dermis, retina, uveal tract, leptomeninges, inner ear, and other tissues.⁵ The ossicles of the middle ear develop from the neural crest⁶ and remain in the mesenchyme until the eighth month, when the surrounding tissue dissolves.⁴ Cutaneous melanomas arise from the malignant transformation of melanocytes in the skin of neural crest lineage. Noncutaneous melanomas are hypothesized to arise from melanoblasts migrating to noncutaneous organs after neural crest cells undergo an epithelial-mesenchymal translation.⁷

Melanoma 5-year survival rates vary based on the melanoma disease stage: 98% for stage 1, 90% for stage 2, 70% for stage 3, and 10% for stage 4. Although early-stage disease mainly is treated with surgery, advanced and unresectable disease is managed with different therapeutic options, including BRAF inhibitors such as vemurafenib, dabrafenib mesylate, and encorafenib; immune checkpoint inhibitors such as ipilimumab, nivolumab, and pembrolizumab; and oncolytic virus such as talimogene laherparepvec.^8,9

Ninety percent of melanomas are of cutaneous origin. Extracutaneous melanomas may be derived from the uvea, leptomeninges, mucous membranes, and gastrointestinal tract.¹⁰ Mucosal melanomas are rare and represent only approximately 1% of all melanomas.¹¹ In order of frequency, primary mucosal melanomas include the head and neck, anorectal region, vulvovaginal region, and urinary tract. UV radiation exposure is an important risk factor for cutaneous melanoma but has not been associated with the development of mucosal melanoma.⁷ In 2019, Altieri et al¹¹ analyzed 1824 cases of mucosal melanoma and found that anatomic site influences survival because mucosal melanomas in the most occult anatomic sites—spinal/central nervous system, lung and pleura, liver, and pancreas—have the worst prognosis, likely because they have already metastasized by the time they are diagnosed. Due to their occult anatomic location and lack of early presenting signs and symptoms, mucosal melanomas are difficult to diagnose at an early stage, resulting in a poorer prognosis compared with cutaneous melanomas. The most important prognostic indicator for cutaneous melanomas of tumor thickness (ie, Breslow depth) provides less prognostic value for patients with mucosal melanoma. Limitations also include the lack of a standardized staging system for mucosal melanoma, but Altieri et al¹¹ found that poorer survival in patients with mucosal melanoma was observed in relation to stage based on the clinical and pathologic tumor-node-metastasis staging system of the Surveillance, Epidemiology, and End Results program. An aggregate 5-year survival estimate of patients diagnosed with mucosal melanoma is 28%, underscoring that mucosal melanoma is an aggressive melanoma that carries a poor prognosis and warrants a more aggressive treatment approach at the time of diagnosis.¹¹

Common treatment of primary middle ear mucosal melanoma involves a multimodality therapy including surgical oncological resection for most patients. Currently, radiation is in use for adjuvant treatment and definitive therapy in unresectable tumors or patients who are poor surgical candidates. Malignant melanoma traditionally was considered radioresistant, yet considerable variability in responsiveness has been observed both within and between tumors. Although there are no defined indications for adjuvant therapy, it is often administered in advanced or recurrent cases and those with positive or close margins. Chemotherapy generally is reserved for patients with systemic disease. The chemotherapeutic agents that have been used in the treatment of patients with melanoma of the middle ear include the alkylating agents dacarbazine, cisplatin, nimustine, paclitaxel, and temozolomide. Also, chemotherapeutic agents that have been reported in the treatment of melanoma of the middle ear include tamoxifen, the selective estrogen receptor inhibitor, and interferon. Most recently, programed cell death protein 1 inhibitors pembrolizumab and nivolumab have been used in the treatment of middle ear melanoma. Outcomes remain poor with a high rate of mortality. Novel immunotherapeutic agents combined with adjuvant radiotherapy have been proposed to improve disease control and survival rates.³

Data on systemic therapies for mucosal melanomas are limited due to the rarity of the disease. Even with the development of novel therapies, outcomes remain poor for mucosal melanomas, and additional treatment strategies are needed. Although proto-oncogene BRAF mutations occur in 50% to 70% of cutaneous melanomas, these mutations are rare in mucosal melanomas.³ In mucosal melanomas, activating mutations of the cell receptor KIT are identified more frequently.⁷ Alterations in proto-oncogene KIT have been found in acral, mucosal, and cutaneous melanoma. KIT mutations were found on exons 11 and 13.¹² Variability in the biology of KIT is suggested. Treatment of melanomas with the KIT mutations with tyrosine inhibitors imatinib and nilotinib have shown variable benefits.¹⁰ In a 2019 study of 44 patients with mucosal melanoma, Moya-Plana et al¹³ found that in cases of unresectable and/or metastatic disease, immunotherapy with pembrolizumab had a better benefit-risk ratio than immune treatment with ipilimumab, a cytotoxic T-cell lymphocyte-associated protein 4 inhibitor.

Primary malignant melanoma of the middle ear is unusual and difficult to diagnose clinically. These melanomas have a poor prognosis and can have distant metastasis including cutaneous metastasis. We present this case to emphasize the need to be aware that melanoma can arise in the middle ear.

To the Editor:

An 82-year-old man presented to our dermatology clinic for a total-body skin examination due to a recently diagnosed primary melanoma of the left middle ear. He reported pain of the left ear and water behind the left eardrum of 1 year’s duration. An otorhinolaryngologist performed surgery due to the severe mastoiditis. A biopsy of the contents of the left middle ear revealed malignant melanoma. Positron emission tomography–computed tomography revealed the mass was mainly located in the anterior aspect of the left middle ear with suspicion of tumor extension into the bony portion of the eustachian tube. No other disease was present. Prior to presentation to dermatology, gross excision of the left middle ear with removal of additional melanoma was confirmed by biopsy, and further analysis revealed v-Raf murine sarcoma viral oncogene (BRAF) was not detected while cellular proto-oncogene receptor kinase (KIT) mutation was detected on exon 13p (K642E).

The patient had no family history of melanoma. He never smoked and did not have contact with hazardous material. Initial examination at our clinic revealed no other suspicious pigmented lesions. After additional negative workup by the oncologist, the patient was presented to the tumor board, and postoperative radiotherapy was recommended to improve local control. Eight months after the patient’s initial diagnosis of the primary middle ear melanoma, a computed tomography–guided right lung biopsy showed metastatic melanoma. After various treatment modalities were discussed with the patient and his family, he was started on pembrolizumab. After 6 months on pembrolizumab, the patient developed autoimmune pneumonitis and pembrolizumab was discontinued. The patient elected to discontinue treatment and died 6 months later.

Malignant melanoma with primary involvement of the middle ear and mastoid mucosa rarely has been reported.^1-3 Primary malignant melanoma of the middle ear mucosa is difficult to diagnose clinically. Difficulty and delay in diagnosis occur because of the location and frequent lack of pathognomonic symptoms of the disease.² A comprehensive literature review by Maxwell et al³ in 2018 of the 10 reported primary middle ear mucosal melanomas found that patients most commonly presented with otorrhea, aural fullness, and hearing loss. Less common symptoms included otalgia, tinnitus, and facial weakness. Clinical examination revealed patients presented with serous otitis and/or a visible mass within the middle ear or external auditory canal. These melanomas demonstrated particularly poor outcomes, with 70% mortality, 20% local recurrence, and 50% distant metastasis. Distant metastases that occurred with primary middle ear mucosal melanoma include lung, liver, intraparotid, abdomen, and cutaneous metastasis.³

The specific pathophysiologic factors underlying the development of primary malignant melanoma of the middle ear mucosa are not known.² The middle ear and its components develop from the first and second pharyngeal arches.⁴ Melanocyte precursors from the neural crest migrate during the seventh or eighth week of embryogenesis. These precursors migrate to the epidermis, various mucosal epithelial, hair follicles, dermis, retina, uveal tract, leptomeninges, inner ear, and other tissues.⁵ The ossicles of the middle ear develop from the neural crest⁶ and remain in the mesenchyme until the eighth month, when the surrounding tissue dissolves.⁴ Cutaneous melanomas arise from the malignant transformation of melanocytes in the skin of neural crest lineage. Noncutaneous melanomas are hypothesized to arise from melanoblasts migrating to noncutaneous organs after neural crest cells undergo an epithelial-mesenchymal translation.⁷

Melanoma 5-year survival rates vary based on the melanoma disease stage: 98% for stage 1, 90% for stage 2, 70% for stage 3, and 10% for stage 4. Although early-stage disease mainly is treated with surgery, advanced and unresectable disease is managed with different therapeutic options, including BRAF inhibitors such as vemurafenib, dabrafenib mesylate, and encorafenib; immune checkpoint inhibitors such as ipilimumab, nivolumab, and pembrolizumab; and oncolytic virus such as talimogene laherparepvec.^8,9

Ninety percent of melanomas are of cutaneous origin. Extracutaneous melanomas may be derived from the uvea, leptomeninges, mucous membranes, and gastrointestinal tract.¹⁰ Mucosal melanomas are rare and represent only approximately 1% of all melanomas.¹¹ In order of frequency, primary mucosal melanomas include the head and neck, anorectal region, vulvovaginal region, and urinary tract. UV radiation exposure is an important risk factor for cutaneous melanoma but has not been associated with the development of mucosal melanoma.⁷ In 2019, Altieri et al¹¹ analyzed 1824 cases of mucosal melanoma and found that anatomic site influences survival because mucosal melanomas in the most occult anatomic sites—spinal/central nervous system, lung and pleura, liver, and pancreas—have the worst prognosis, likely because they have already metastasized by the time they are diagnosed. Due to their occult anatomic location and lack of early presenting signs and symptoms, mucosal melanomas are difficult to diagnose at an early stage, resulting in a poorer prognosis compared with cutaneous melanomas. The most important prognostic indicator for cutaneous melanomas of tumor thickness (ie, Breslow depth) provides less prognostic value for patients with mucosal melanoma. Limitations also include the lack of a standardized staging system for mucosal melanoma, but Altieri et al¹¹ found that poorer survival in patients with mucosal melanoma was observed in relation to stage based on the clinical and pathologic tumor-node-metastasis staging system of the Surveillance, Epidemiology, and End Results program. An aggregate 5-year survival estimate of patients diagnosed with mucosal melanoma is 28%, underscoring that mucosal melanoma is an aggressive melanoma that carries a poor prognosis and warrants a more aggressive treatment approach at the time of diagnosis.¹¹

Common treatment of primary middle ear mucosal melanoma involves a multimodality therapy including surgical oncological resection for most patients. Currently, radiation is in use for adjuvant treatment and definitive therapy in unresectable tumors or patients who are poor surgical candidates. Malignant melanoma traditionally was considered radioresistant, yet considerable variability in responsiveness has been observed both within and between tumors. Although there are no defined indications for adjuvant therapy, it is often administered in advanced or recurrent cases and those with positive or close margins. Chemotherapy generally is reserved for patients with systemic disease. The chemotherapeutic agents that have been used in the treatment of patients with melanoma of the middle ear include the alkylating agents dacarbazine, cisplatin, nimustine, paclitaxel, and temozolomide. Also, chemotherapeutic agents that have been reported in the treatment of melanoma of the middle ear include tamoxifen, the selective estrogen receptor inhibitor, and interferon. Most recently, programed cell death protein 1 inhibitors pembrolizumab and nivolumab have been used in the treatment of middle ear melanoma. Outcomes remain poor with a high rate of mortality. Novel immunotherapeutic agents combined with adjuvant radiotherapy have been proposed to improve disease control and survival rates.³

Data on systemic therapies for mucosal melanomas are limited due to the rarity of the disease. Even with the development of novel therapies, outcomes remain poor for mucosal melanomas, and additional treatment strategies are needed. Although proto-oncogene BRAF mutations occur in 50% to 70% of cutaneous melanomas, these mutations are rare in mucosal melanomas.³ In mucosal melanomas, activating mutations of the cell receptor KIT are identified more frequently.⁷ Alterations in proto-oncogene KIT have been found in acral, mucosal, and cutaneous melanoma. KIT mutations were found on exons 11 and 13.¹² Variability in the biology of KIT is suggested. Treatment of melanomas with the KIT mutations with tyrosine inhibitors imatinib and nilotinib have shown variable benefits.¹⁰ In a 2019 study of 44 patients with mucosal melanoma, Moya-Plana et al¹³ found that in cases of unresectable and/or metastatic disease, immunotherapy with pembrolizumab had a better benefit-risk ratio than immune treatment with ipilimumab, a cytotoxic T-cell lymphocyte-associated protein 4 inhibitor.

Primary malignant melanoma of the middle ear is unusual and difficult to diagnose clinically. These melanomas have a poor prognosis and can have distant metastasis including cutaneous metastasis. We present this case to emphasize the need to be aware that melanoma can arise in the middle ear.

To the Editor:

The posttraumatic pseudolipoma (PTL) is a painless localized mass comprised of unencapsulated adipose tissue that develops at the site of acute or prolonged blunt soft tissue trauma. It may be round or fusiform in shape and has areas of saponification leading to fat necrosis.¹ Posttraumatic pseudolipomas are 12 times more likely to occur in females, which may be attributed to sex-determined adipose tissue distribution or cosmetic concerns.² Most PTLs are found in areas of the body with high adiposity, including the hip, thigh, and gluteal regions.³ A patient history of a traumatic event resulting in a hematoma and a subsequent latent period of several months to years before the pseudolipoma formation occurs is common.^1,2,4-6

A 27-year-old woman presented to the family medicine clinic for examination of a deformity on the right buttock. She noticed a soft protruding mass months after landing on the buttocks and on top of a stick during routine physical training. Prior ultrasonography of the deformity proved unhelpful in determining the etiology. Physical examination revealed a protruding, 2-cm, flesh-colored mass on the right buttock intergluteal fold that was soft, compressible, and nontender (Figure 1). There was no capsule, nodule, loculation, or sinus tract. The patient underwent excisional resection with findings of benign-appearing unencapsulated adipose tissue (Figure 2). The wound was closed without difficulty. After several weeks, she had a well-healing scar without contour deficits of the buttocks. Two to 3 months after the initial repair, the patient presented to the family medicine clinic with recurrence of the fatty protrusion. She was referred for consultation and definitive management to a plastic surgeon but was lost to follow up.

In a systematic review of the literature to research pathogenesis theories, a PubMed search of articles indexed for MEDLINE using the terms trauma and pseudolipoma, lipoma, fat, or adipose yielded 45 citations, with only 10 publications addressing the pathology specific to pseudolipomas. Two leading theories of the pathogenesis of PTLs include the adipose herniation pathway and the inflammatory proliferation pathway.^4,5

Adipose tissue comprises fat lobules that are organized underneath the supportive elastic fascial layers. Injury from forces exceeding the fascial strength is the basis for the oldest pathogenesis theory. The adipose herniation theory suggests that fat lobules are displaced through the damaged septae, allowing for the development of an epidermal pseudolipoma at the site of blunt trauma.⁷ This theory has been supported by many case reports; however, more recent reports have identified a larger number of PTL cases that showed no identifiable disruptions in the fascia.^1,4,8

In 1997, the inflammatory proliferation theory began to gain attention. The theory describes how local tissue trauma leads to the release of inflammatory cytokines, which successively signals the development of preadipocytes or adipose tissue–derived stem cells (ASCs) into mature adipocytes.⁴ Most patients report a history of a hematoma in the area of pseudolipoma development, which strongly supports this newer theory. Studies exploring hematomas have found elevated levels of growth factors and inflammatory markers.^2,9 In particular, tumor necrosis factor α, peroxisome proliferator–activated receptor γ, vascular endothelial growth factor, and IL-6 and IL-8 may foster an environment in which adipogenic cells are both chemotaxed to the area of trauma and differentiated to white adipose tissue.^2,10

Despite addressing the role of the preadipocyte, the available research fails to address the general development of mesenchymal cells into the preadipocyte. White adipose tissue develops at sites of neovascularization and frequently has been observed spreading into the nearby tissue toward other blood vessels. Furthermore, these white adipose tissue expansions remain reliant on multiple growth factors and cell-signaling molecules.¹⁰ Numerous investigations into stem cell grafting have found that implantation of ASCs in vivo within animal models does not result in the proliferation and differentiation of ASCs unless specific conditions have been met such as prior tissue injury or immunodeficiency.^10-12 These investigations support and expand on the inflammatory proliferation pathway. Thus, most of the true PTLs in the available research appear as de novo tumors and are more congruent with the inflammatory proliferation model.^1,2,4-6,8

Typical treatment of a PTL is surgical excision or liposuction depending on the pathology and size of the pseudolipoma. Biopsy examination prior to liposuction is critical for evaluation of liposarcoma and may help identify damage to Scarpa fascia. Recurrence of a PTL is rare regardless of treatment method; however, in a study of 31 PTL cases, only 6 were pathologically identified as PTLs without fibrous material.¹

Our patient experienced a blunt trauma to the buttocks and subsequently developed a PTL that was surgically excised and recurred within 3 months. Research surrounding the pathogenesis of the PTL has evolved from the theory of physical herniation of adipose tissue to an inflammatory differentiation of preadipocytes, but there is still much to learn about how and why it occurs and the mesenchymal differentiation following tissue injury.

To the Editor:

The posttraumatic pseudolipoma (PTL) is a painless localized mass comprised of unencapsulated adipose tissue that develops at the site of acute or prolonged blunt soft tissue trauma. It may be round or fusiform in shape and has areas of saponification leading to fat necrosis.¹ Posttraumatic pseudolipomas are 12 times more likely to occur in females, which may be attributed to sex-determined adipose tissue distribution or cosmetic concerns.² Most PTLs are found in areas of the body with high adiposity, including the hip, thigh, and gluteal regions.³ A patient history of a traumatic event resulting in a hematoma and a subsequent latent period of several months to years before the pseudolipoma formation occurs is common.^1,2,4-6

A 27-year-old woman presented to the family medicine clinic for examination of a deformity on the right buttock. She noticed a soft protruding mass months after landing on the buttocks and on top of a stick during routine physical training. Prior ultrasonography of the deformity proved unhelpful in determining the etiology. Physical examination revealed a protruding, 2-cm, flesh-colored mass on the right buttock intergluteal fold that was soft, compressible, and nontender (Figure 1). There was no capsule, nodule, loculation, or sinus tract. The patient underwent excisional resection with findings of benign-appearing unencapsulated adipose tissue (Figure 2). The wound was closed without difficulty. After several weeks, she had a well-healing scar without contour deficits of the buttocks. Two to 3 months after the initial repair, the patient presented to the family medicine clinic with recurrence of the fatty protrusion. She was referred for consultation and definitive management to a plastic surgeon but was lost to follow up.

In a systematic review of the literature to research pathogenesis theories, a PubMed search of articles indexed for MEDLINE using the terms trauma and pseudolipoma, lipoma, fat, or adipose yielded 45 citations, with only 10 publications addressing the pathology specific to pseudolipomas. Two leading theories of the pathogenesis of PTLs include the adipose herniation pathway and the inflammatory proliferation pathway.^4,5

Adipose tissue comprises fat lobules that are organized underneath the supportive elastic fascial layers. Injury from forces exceeding the fascial strength is the basis for the oldest pathogenesis theory. The adipose herniation theory suggests that fat lobules are displaced through the damaged septae, allowing for the development of an epidermal pseudolipoma at the site of blunt trauma.⁷ This theory has been supported by many case reports; however, more recent reports have identified a larger number of PTL cases that showed no identifiable disruptions in the fascia.^1,4,8

In 1997, the inflammatory proliferation theory began to gain attention. The theory describes how local tissue trauma leads to the release of inflammatory cytokines, which successively signals the development of preadipocytes or adipose tissue–derived stem cells (ASCs) into mature adipocytes.⁴ Most patients report a history of a hematoma in the area of pseudolipoma development, which strongly supports this newer theory. Studies exploring hematomas have found elevated levels of growth factors and inflammatory markers.^2,9 In particular, tumor necrosis factor α, peroxisome proliferator–activated receptor γ, vascular endothelial growth factor, and IL-6 and IL-8 may foster an environment in which adipogenic cells are both chemotaxed to the area of trauma and differentiated to white adipose tissue.^2,10

Despite addressing the role of the preadipocyte, the available research fails to address the general development of mesenchymal cells into the preadipocyte. White adipose tissue develops at sites of neovascularization and frequently has been observed spreading into the nearby tissue toward other blood vessels. Furthermore, these white adipose tissue expansions remain reliant on multiple growth factors and cell-signaling molecules.¹⁰ Numerous investigations into stem cell grafting have found that implantation of ASCs in vivo within animal models does not result in the proliferation and differentiation of ASCs unless specific conditions have been met such as prior tissue injury or immunodeficiency.^10-12 These investigations support and expand on the inflammatory proliferation pathway. Thus, most of the true PTLs in the available research appear as de novo tumors and are more congruent with the inflammatory proliferation model.^1,2,4-6,8

Typical treatment of a PTL is surgical excision or liposuction depending on the pathology and size of the pseudolipoma. Biopsy examination prior to liposuction is critical for evaluation of liposarcoma and may help identify damage to Scarpa fascia. Recurrence of a PTL is rare regardless of treatment method; however, in a study of 31 PTL cases, only 6 were pathologically identified as PTLs without fibrous material.¹

Our patient experienced a blunt trauma to the buttocks and subsequently developed a PTL that was surgically excised and recurred within 3 months. Research surrounding the pathogenesis of the PTL has evolved from the theory of physical herniation of adipose tissue to an inflammatory differentiation of preadipocytes, but there is still much to learn about how and why it occurs and the mesenchymal differentiation following tissue injury.

To the Editor:

The posttraumatic pseudolipoma (PTL) is a painless localized mass comprised of unencapsulated adipose tissue that develops at the site of acute or prolonged blunt soft tissue trauma. It may be round or fusiform in shape and has areas of saponification leading to fat necrosis.¹ Posttraumatic pseudolipomas are 12 times more likely to occur in females, which may be attributed to sex-determined adipose tissue distribution or cosmetic concerns.² Most PTLs are found in areas of the body with high adiposity, including the hip, thigh, and gluteal regions.³ A patient history of a traumatic event resulting in a hematoma and a subsequent latent period of several months to years before the pseudolipoma formation occurs is common.^1,2,4-6

A 27-year-old woman presented to the family medicine clinic for examination of a deformity on the right buttock. She noticed a soft protruding mass months after landing on the buttocks and on top of a stick during routine physical training. Prior ultrasonography of the deformity proved unhelpful in determining the etiology. Physical examination revealed a protruding, 2-cm, flesh-colored mass on the right buttock intergluteal fold that was soft, compressible, and nontender (Figure 1). There was no capsule, nodule, loculation, or sinus tract. The patient underwent excisional resection with findings of benign-appearing unencapsulated adipose tissue (Figure 2). The wound was closed without difficulty. After several weeks, she had a well-healing scar without contour deficits of the buttocks. Two to 3 months after the initial repair, the patient presented to the family medicine clinic with recurrence of the fatty protrusion. She was referred for consultation and definitive management to a plastic surgeon but was lost to follow up.

In a systematic review of the literature to research pathogenesis theories, a PubMed search of articles indexed for MEDLINE using the terms trauma and pseudolipoma, lipoma, fat, or adipose yielded 45 citations, with only 10 publications addressing the pathology specific to pseudolipomas. Two leading theories of the pathogenesis of PTLs include the adipose herniation pathway and the inflammatory proliferation pathway.^4,5

Adipose tissue comprises fat lobules that are organized underneath the supportive elastic fascial layers. Injury from forces exceeding the fascial strength is the basis for the oldest pathogenesis theory. The adipose herniation theory suggests that fat lobules are displaced through the damaged septae, allowing for the development of an epidermal pseudolipoma at the site of blunt trauma.⁷ This theory has been supported by many case reports; however, more recent reports have identified a larger number of PTL cases that showed no identifiable disruptions in the fascia.^1,4,8

In 1997, the inflammatory proliferation theory began to gain attention. The theory describes how local tissue trauma leads to the release of inflammatory cytokines, which successively signals the development of preadipocytes or adipose tissue–derived stem cells (ASCs) into mature adipocytes.⁴ Most patients report a history of a hematoma in the area of pseudolipoma development, which strongly supports this newer theory. Studies exploring hematomas have found elevated levels of growth factors and inflammatory markers.^2,9 In particular, tumor necrosis factor α, peroxisome proliferator–activated receptor γ, vascular endothelial growth factor, and IL-6 and IL-8 may foster an environment in which adipogenic cells are both chemotaxed to the area of trauma and differentiated to white adipose tissue.^2,10

Despite addressing the role of the preadipocyte, the available research fails to address the general development of mesenchymal cells into the preadipocyte. White adipose tissue develops at sites of neovascularization and frequently has been observed spreading into the nearby tissue toward other blood vessels. Furthermore, these white adipose tissue expansions remain reliant on multiple growth factors and cell-signaling molecules.¹⁰ Numerous investigations into stem cell grafting have found that implantation of ASCs in vivo within animal models does not result in the proliferation and differentiation of ASCs unless specific conditions have been met such as prior tissue injury or immunodeficiency.^10-12 These investigations support and expand on the inflammatory proliferation pathway. Thus, most of the true PTLs in the available research appear as de novo tumors and are more congruent with the inflammatory proliferation model.^1,2,4-6,8

Typical treatment of a PTL is surgical excision or liposuction depending on the pathology and size of the pseudolipoma. Biopsy examination prior to liposuction is critical for evaluation of liposarcoma and may help identify damage to Scarpa fascia. Recurrence of a PTL is rare regardless of treatment method; however, in a study of 31 PTL cases, only 6 were pathologically identified as PTLs without fibrous material.¹

Our patient experienced a blunt trauma to the buttocks and subsequently developed a PTL that was surgically excised and recurred within 3 months. Research surrounding the pathogenesis of the PTL has evolved from the theory of physical herniation of adipose tissue to an inflammatory differentiation of preadipocytes, but there is still much to learn about how and why it occurs and the mesenchymal differentiation following tissue injury.

The Diagnosis: Immunotherapy-Related Lichenoid Drug Eruption

Direct immunofluorescence was negative, and histopathology revealed a lichenoid interface dermatitis, minimal parakeratosis, and saw-toothed rete ridges (Figure 1). He was diagnosed with an immunotherapyrelated lichenoid drug eruption based on the morphology of the skin lesions and clinicopathologic correlation. Bullous pemphigoid and lichen planus pemphigoides were ruled out given the negative direct immunofluorescence findings. Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) was not consistent with the clinical presentation, especially given the lack of mucosal findings. The histology also was not consistent, as the biopsy specimen lacked apoptotic and necrotic keratinocytes to the degree seen in SJS/TEN and also had a greater degree of inflammatory infiltrate. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome was ruled out given the lack of systemic findings, including facial swelling and lymphadenopathy and the clinical appearance of the rash. No morbilliform features were present, which is the most common presentation of DRESS syndrome.

Checkpoint inhibitor (CPI) therapy has become the cornerstone in management of certain advanced malignancies.¹ Checkpoint inhibitors block cytotoxic T lymphocyte–associated protein 4, programmed cell death-1, and/or programmed cell death ligand-1, allowing activated T cells to infiltrate the tumor microenvironment and destroy malignant cells. Checkpoint inhibitors are approved for the treatment of melanoma, cutaneous squamous cell carcinoma, and Merkel cell carcinoma and are being investigated in various other cutaneous and soft tissue malignancies.^1-3

Although CPIs have shown substantial efficacy in the management of advanced malignancies, immune-related adverse events (AEs) are common due to nonspecific immune activation.² Immune-related cutaneous AEs are the most common immune-related AEs, occurring in 30% to 50% of patients who undergo treatment.^2-5 Common immune-related cutaneous AEs include maculopapular, psoriasiform, and lichenoid dermatitis, as well as pruritus without dermatitis.^2,3,6 Other reactions include but are not limited to bullous pemphigoid, vitiligolike depigmentation, and alopecia.^2,3 Immune-related cutaneous AEs usually are self-limited; however, severe life-threatening reactions such as the spectrum of SJS/TEN and DRESS syndrome also can occur.^2-4 Immune-related cutaneous AEs are graded based on the Common Terminology Criteria for Adverse Events: grade 1 reactions are asymptomatic and cover less than 10% of the patient’s body surface area (BSA), grade 2 reactions have mild symptoms and cover 10% to 30% of the patient’s BSA, grade 3 reactions have moderate to severe symptoms and cover greater than 30% of the patient’s BSA, and grade 4 reactions are life-threatening.^2,3 With prompt recognition and adequate treatment, mild to moderate immune-related cutaneous AEs—grades 1 and 2—largely are reversible, and less than 5% require discontinuation of therapy.^2,3,6 It has been suggested that immune-related cutaneous AEs may be a positive prognostic factor in the treatment of underlying malignancy, indicating adequate immune activation targeting the malignant cells.⁶

Although our patient had some typical violaceous, flat-topped papules and plaques with Wickham striae, he also had atypical findings for a lichenoid reaction. Given the endorsement of blisters, it is possible that some of these lesions initially were bullous and subsequently ruptured, leaving behind erosions. However, in other areas, there also were eroded papules and ulcerations without a reported history of excoriation, scratching, picking, or prior bullae, including difficult-to-reach areas such as the back. It is favored that these lesions represented a robust lichenoid dermatitis leading to erosive and ulcerated lesions, similar to the formation of bullous lichen planus. Lichenoid eruptions secondary to immunotherapy are well-known phenomena, but a PubMed search of articles indexed for MEDLINE using the terms ulcer, lichenoid, and immunotherapy revealed only 2 cases of ulcerative lichenoid eruptions: a localized digital erosive lichenoid dermatitis and a widespread ulcerative lichenoid drug eruption without true erosions.7,8 However, widespread erosive and ulcerated lichenoid reactions are rare.

Lichenoid eruptions most strongly are associated with anti–programmed cell death-1/ programmed cell death ligand-1 therapy, occurring in 20% of patients undergoing treatment.³ Lichenoid eruptions present as discrete, pruritic, erythematous, violaceous papules and plaques on the chest and back and rarely may involve the limbs, palmoplantar surfaces, and oral mucosa.^2,3,6 Histopathologic features include a dense bandlike lymphocytic infiltrate in the dermis with scattered apoptotic keratinocytes in the basal layer of the epidermis.^2,4,6 Grades 1 to 2 lesions can be managed with high-potency topical corticosteroids without CPI dose interruption, with more extensive grade 2 lesions requiring systemic corticosteroids.^2,6,9 Lichenoid eruptions grade 3 or higher also require systemic corticosteroid therapy CPI therapy cessation until the eruption has receded to grade 0 to 1.² Alternative treatment options for high-grade toxicity include phototherapy and acitretin.^2,4,9

Our patient was treated with cessation of immunotherapy and initiation of a systemic corticosteroid taper, acitretin, and narrowband UVB therapy. After 6 weeks of treatment, the pain and pruritus improved and the rash had resolved in some areas while it had taken on a more classic lichenoid appearance with violaceous scaly papules and plaques (Figure 2) in areas of prior ulcers and erosions. He no longer had any bullae, erosions, or ulcers.

The Diagnosis: Immunotherapy-Related Lichenoid Drug Eruption

Direct immunofluorescence was negative, and histopathology revealed a lichenoid interface dermatitis, minimal parakeratosis, and saw-toothed rete ridges (Figure 1). He was diagnosed with an immunotherapyrelated lichenoid drug eruption based on the morphology of the skin lesions and clinicopathologic correlation. Bullous pemphigoid and lichen planus pemphigoides were ruled out given the negative direct immunofluorescence findings. Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) was not consistent with the clinical presentation, especially given the lack of mucosal findings. The histology also was not consistent, as the biopsy specimen lacked apoptotic and necrotic keratinocytes to the degree seen in SJS/TEN and also had a greater degree of inflammatory infiltrate. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome was ruled out given the lack of systemic findings, including facial swelling and lymphadenopathy and the clinical appearance of the rash. No morbilliform features were present, which is the most common presentation of DRESS syndrome.

Checkpoint inhibitor (CPI) therapy has become the cornerstone in management of certain advanced malignancies.¹ Checkpoint inhibitors block cytotoxic T lymphocyte–associated protein 4, programmed cell death-1, and/or programmed cell death ligand-1, allowing activated T cells to infiltrate the tumor microenvironment and destroy malignant cells. Checkpoint inhibitors are approved for the treatment of melanoma, cutaneous squamous cell carcinoma, and Merkel cell carcinoma and are being investigated in various other cutaneous and soft tissue malignancies.^1-3

Although CPIs have shown substantial efficacy in the management of advanced malignancies, immune-related adverse events (AEs) are common due to nonspecific immune activation.² Immune-related cutaneous AEs are the most common immune-related AEs, occurring in 30% to 50% of patients who undergo treatment.^2-5 Common immune-related cutaneous AEs include maculopapular, psoriasiform, and lichenoid dermatitis, as well as pruritus without dermatitis.^2,3,6 Other reactions include but are not limited to bullous pemphigoid, vitiligolike depigmentation, and alopecia.^2,3 Immune-related cutaneous AEs usually are self-limited; however, severe life-threatening reactions such as the spectrum of SJS/TEN and DRESS syndrome also can occur.^2-4 Immune-related cutaneous AEs are graded based on the Common Terminology Criteria for Adverse Events: grade 1 reactions are asymptomatic and cover less than 10% of the patient’s body surface area (BSA), grade 2 reactions have mild symptoms and cover 10% to 30% of the patient’s BSA, grade 3 reactions have moderate to severe symptoms and cover greater than 30% of the patient’s BSA, and grade 4 reactions are life-threatening.^2,3 With prompt recognition and adequate treatment, mild to moderate immune-related cutaneous AEs—grades 1 and 2—largely are reversible, and less than 5% require discontinuation of therapy.^2,3,6 It has been suggested that immune-related cutaneous AEs may be a positive prognostic factor in the treatment of underlying malignancy, indicating adequate immune activation targeting the malignant cells.⁶

Although our patient had some typical violaceous, flat-topped papules and plaques with Wickham striae, he also had atypical findings for a lichenoid reaction. Given the endorsement of blisters, it is possible that some of these lesions initially were bullous and subsequently ruptured, leaving behind erosions. However, in other areas, there also were eroded papules and ulcerations without a reported history of excoriation, scratching, picking, or prior bullae, including difficult-to-reach areas such as the back. It is favored that these lesions represented a robust lichenoid dermatitis leading to erosive and ulcerated lesions, similar to the formation of bullous lichen planus. Lichenoid eruptions secondary to immunotherapy are well-known phenomena, but a PubMed search of articles indexed for MEDLINE using the terms ulcer, lichenoid, and immunotherapy revealed only 2 cases of ulcerative lichenoid eruptions: a localized digital erosive lichenoid dermatitis and a widespread ulcerative lichenoid drug eruption without true erosions.7,8 However, widespread erosive and ulcerated lichenoid reactions are rare.

Lichenoid eruptions most strongly are associated with anti–programmed cell death-1/ programmed cell death ligand-1 therapy, occurring in 20% of patients undergoing treatment.³ Lichenoid eruptions present as discrete, pruritic, erythematous, violaceous papules and plaques on the chest and back and rarely may involve the limbs, palmoplantar surfaces, and oral mucosa.^2,3,6 Histopathologic features include a dense bandlike lymphocytic infiltrate in the dermis with scattered apoptotic keratinocytes in the basal layer of the epidermis.^2,4,6 Grades 1 to 2 lesions can be managed with high-potency topical corticosteroids without CPI dose interruption, with more extensive grade 2 lesions requiring systemic corticosteroids.^2,6,9 Lichenoid eruptions grade 3 or higher also require systemic corticosteroid therapy CPI therapy cessation until the eruption has receded to grade 0 to 1.² Alternative treatment options for high-grade toxicity include phototherapy and acitretin.^2,4,9

Our patient was treated with cessation of immunotherapy and initiation of a systemic corticosteroid taper, acitretin, and narrowband UVB therapy. After 6 weeks of treatment, the pain and pruritus improved and the rash had resolved in some areas while it had taken on a more classic lichenoid appearance with violaceous scaly papules and plaques (Figure 2) in areas of prior ulcers and erosions. He no longer had any bullae, erosions, or ulcers.

The Diagnosis: Immunotherapy-Related Lichenoid Drug Eruption

Direct immunofluorescence was negative, and histopathology revealed a lichenoid interface dermatitis, minimal parakeratosis, and saw-toothed rete ridges (Figure 1). He was diagnosed with an immunotherapyrelated lichenoid drug eruption based on the morphology of the skin lesions and clinicopathologic correlation. Bullous pemphigoid and lichen planus pemphigoides were ruled out given the negative direct immunofluorescence findings. Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) was not consistent with the clinical presentation, especially given the lack of mucosal findings. The histology also was not consistent, as the biopsy specimen lacked apoptotic and necrotic keratinocytes to the degree seen in SJS/TEN and also had a greater degree of inflammatory infiltrate. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome was ruled out given the lack of systemic findings, including facial swelling and lymphadenopathy and the clinical appearance of the rash. No morbilliform features were present, which is the most common presentation of DRESS syndrome.

Checkpoint inhibitor (CPI) therapy has become the cornerstone in management of certain advanced malignancies.¹ Checkpoint inhibitors block cytotoxic T lymphocyte–associated protein 4, programmed cell death-1, and/or programmed cell death ligand-1, allowing activated T cells to infiltrate the tumor microenvironment and destroy malignant cells. Checkpoint inhibitors are approved for the treatment of melanoma, cutaneous squamous cell carcinoma, and Merkel cell carcinoma and are being investigated in various other cutaneous and soft tissue malignancies.^1-3

Although CPIs have shown substantial efficacy in the management of advanced malignancies, immune-related adverse events (AEs) are common due to nonspecific immune activation.² Immune-related cutaneous AEs are the most common immune-related AEs, occurring in 30% to 50% of patients who undergo treatment.^2-5 Common immune-related cutaneous AEs include maculopapular, psoriasiform, and lichenoid dermatitis, as well as pruritus without dermatitis.^2,3,6 Other reactions include but are not limited to bullous pemphigoid, vitiligolike depigmentation, and alopecia.^2,3 Immune-related cutaneous AEs usually are self-limited; however, severe life-threatening reactions such as the spectrum of SJS/TEN and DRESS syndrome also can occur.^2-4 Immune-related cutaneous AEs are graded based on the Common Terminology Criteria for Adverse Events: grade 1 reactions are asymptomatic and cover less than 10% of the patient’s body surface area (BSA), grade 2 reactions have mild symptoms and cover 10% to 30% of the patient’s BSA, grade 3 reactions have moderate to severe symptoms and cover greater than 30% of the patient’s BSA, and grade 4 reactions are life-threatening.^2,3 With prompt recognition and adequate treatment, mild to moderate immune-related cutaneous AEs—grades 1 and 2—largely are reversible, and less than 5% require discontinuation of therapy.^2,3,6 It has been suggested that immune-related cutaneous AEs may be a positive prognostic factor in the treatment of underlying malignancy, indicating adequate immune activation targeting the malignant cells.⁶

Although our patient had some typical violaceous, flat-topped papules and plaques with Wickham striae, he also had atypical findings for a lichenoid reaction. Given the endorsement of blisters, it is possible that some of these lesions initially were bullous and subsequently ruptured, leaving behind erosions. However, in other areas, there also were eroded papules and ulcerations without a reported history of excoriation, scratching, picking, or prior bullae, including difficult-to-reach areas such as the back. It is favored that these lesions represented a robust lichenoid dermatitis leading to erosive and ulcerated lesions, similar to the formation of bullous lichen planus. Lichenoid eruptions secondary to immunotherapy are well-known phenomena, but a PubMed search of articles indexed for MEDLINE using the terms ulcer, lichenoid, and immunotherapy revealed only 2 cases of ulcerative lichenoid eruptions: a localized digital erosive lichenoid dermatitis and a widespread ulcerative lichenoid drug eruption without true erosions.7,8 However, widespread erosive and ulcerated lichenoid reactions are rare.

Lichenoid eruptions most strongly are associated with anti–programmed cell death-1/ programmed cell death ligand-1 therapy, occurring in 20% of patients undergoing treatment.³ Lichenoid eruptions present as discrete, pruritic, erythematous, violaceous papules and plaques on the chest and back and rarely may involve the limbs, palmoplantar surfaces, and oral mucosa.^2,3,6 Histopathologic features include a dense bandlike lymphocytic infiltrate in the dermis with scattered apoptotic keratinocytes in the basal layer of the epidermis.^2,4,6 Grades 1 to 2 lesions can be managed with high-potency topical corticosteroids without CPI dose interruption, with more extensive grade 2 lesions requiring systemic corticosteroids.^2,6,9 Lichenoid eruptions grade 3 or higher also require systemic corticosteroid therapy CPI therapy cessation until the eruption has receded to grade 0 to 1.² Alternative treatment options for high-grade toxicity include phototherapy and acitretin.^2,4,9

Our patient was treated with cessation of immunotherapy and initiation of a systemic corticosteroid taper, acitretin, and narrowband UVB therapy. After 6 weeks of treatment, the pain and pruritus improved and the rash had resolved in some areas while it had taken on a more classic lichenoid appearance with violaceous scaly papules and plaques (Figure 2) in areas of prior ulcers and erosions. He no longer had any bullae, erosions, or ulcers.

To the Editor:

Atopic diseases, specifically atopic dermatitis (AD) and alopecia areata (AA), are at the forefront of a new era in dermatology involving molecular-directed therapy. Dupilumab is one specific example, having received US Food and Drug Administration approval in March 2017 for the treatment of adults with moderate to severe AD.¹ It currently is being investigated for use in pediatric AD. The most commonly reported side effects associated with the use of dupilumab include headaches, conjunctivitis, keratitis, blepharitis, nasopharyngitis, and injection-site reactions.² We discuss a case of hair regrowth in a patient who was previously diagnosed with AA after treatment with dupilumab for refractory AD.

A 65-year-old White man presented with a history of AD since childhood. Additional medical history included hyperlipidemia; herpes simplex virus infection; asthma; and a diagnosis of AA 6 years prior, which eventually progressed to alopecia universalis. Physical examination demonstrated scattered erythematous lichenified plaques with excoriations involving the arms, legs, and trunk. The patient’s face and scalp were spared of lesions. Complete loss of body hair including the eyelashes and eyebrows also was noted, which was consistent with alopecia universalis.

The patient was started on dupilumab for refractory AD after multiple courses of topical and systemic steroids failed. Prior treatment for AD did not include immunosuppressive or light therapy. The standard dosage of dupilumab was administered, which consisted of a 600-mg subcutaneous loading dose, followed by 300 mg every 2 weeks. There was no concurrent topical corticosteroid or topical calcineurin inhibitor prescribed. After 1 month of treatment with dupilumab, near-complete resolution of the patient’s AD was noted, and after 10 months of treatment, the patient experienced regrowth of the eyelashes, terminal hairs of the beard area (Figure), and vellus hairs of the eyebrows. This hair regrowth persists today with continued dupilumab treatment, and the patient has experienced no additional side effects.

Multiple retrospective and meta-analysis studies have demonstrated a high occurrence of AD comorbid with AA, which strongly suggests a common pathogenesis.^3,4 Atopic dermatitis is an inflammatory skin disease mediated by IL-4, IL-5, and IL-13 of the helper T-cell type 2 (T_H2) pathway.¹ Dupilumab is a human monoclonal antibody that binds to IL-4Rα, which also is found in IL-13 receptors. Dupilumab prevents T_H2 pathway-related downstream signaling effects of both cytokines. Although this effect was originally utilized to suppress the T_H2-mediated signaling in AD, our patient and others have demonstrated successful hair regrowth with dupilumab, which likely stems from a similar T_H2-related antagonism in AA.^5,6

The cause of AA is unknown, but IL-4 and IL-13 of the T_H2 pathway have been implicated, which renders support for the therapeutic effect of dupilumab in the treatment of AA. Scalp samples of patients with AA have demonstrated upregulation of T_H2, helper T-cell type 1 (T_H1), and IL-23 cytokines, suggesting efficacy with the use of anti-T_H2, anti-T_H1, and anti–IL-23 therapies.⁷ Polymerase chain reaction testing performed on serum samples in patients with AA displayed marked elevation of T_H2 cytokines, notably IL-13, which were reduced following intralesional corticosteroid treatment.⁸ It also has been demonstrated that multiple T_H2-related genes contribute to the genetic susceptibility of developing AA, specifically IL-4 and IL-13.^9,10

Prior case reports have shown contradicting effects (dupilumab-induced AA), which are speculated to be caused by a stronger T_H1 response from T_H2 suppression.^11,12 In one report, dupilumab was initiated for AD refractory to multiple topical and oral interventions. New-onset hair loss to the scalp was noted after 18 weeks of therapy. Twenty-six weeks into therapy with dupilumab, full hair regrowth was then reported.¹¹ Despite this report, our patient’s hair regrowth after the use of dupilumab for refractory AD further strengthens support for the use of dupilumab as a potential therapy for alopecia universalis and other lymphocyte-mediated hair loss conditions. However, a large disparity in response time and an overall slower progression of hair regrowth reported in our case separate it from other reports of rapid voluminous hair regrowth.^5,6 Our findings support the potential use of dupilumab in the treatment of patients with AA.

To the Editor:

Atopic diseases, specifically atopic dermatitis (AD) and alopecia areata (AA), are at the forefront of a new era in dermatology involving molecular-directed therapy. Dupilumab is one specific example, having received US Food and Drug Administration approval in March 2017 for the treatment of adults with moderate to severe AD.¹ It currently is being investigated for use in pediatric AD. The most commonly reported side effects associated with the use of dupilumab include headaches, conjunctivitis, keratitis, blepharitis, nasopharyngitis, and injection-site reactions.² We discuss a case of hair regrowth in a patient who was previously diagnosed with AA after treatment with dupilumab for refractory AD.

A 65-year-old White man presented with a history of AD since childhood. Additional medical history included hyperlipidemia; herpes simplex virus infection; asthma; and a diagnosis of AA 6 years prior, which eventually progressed to alopecia universalis. Physical examination demonstrated scattered erythematous lichenified plaques with excoriations involving the arms, legs, and trunk. The patient’s face and scalp were spared of lesions. Complete loss of body hair including the eyelashes and eyebrows also was noted, which was consistent with alopecia universalis.

The patient was started on dupilumab for refractory AD after multiple courses of topical and systemic steroids failed. Prior treatment for AD did not include immunosuppressive or light therapy. The standard dosage of dupilumab was administered, which consisted of a 600-mg subcutaneous loading dose, followed by 300 mg every 2 weeks. There was no concurrent topical corticosteroid or topical calcineurin inhibitor prescribed. After 1 month of treatment with dupilumab, near-complete resolution of the patient’s AD was noted, and after 10 months of treatment, the patient experienced regrowth of the eyelashes, terminal hairs of the beard area (Figure), and vellus hairs of the eyebrows. This hair regrowth persists today with continued dupilumab treatment, and the patient has experienced no additional side effects.

Multiple retrospective and meta-analysis studies have demonstrated a high occurrence of AD comorbid with AA, which strongly suggests a common pathogenesis.^3,4 Atopic dermatitis is an inflammatory skin disease mediated by IL-4, IL-5, and IL-13 of the helper T-cell type 2 (T_H2) pathway.¹ Dupilumab is a human monoclonal antibody that binds to IL-4Rα, which also is found in IL-13 receptors. Dupilumab prevents T_H2 pathway-related downstream signaling effects of both cytokines. Although this effect was originally utilized to suppress the T_H2-mediated signaling in AD, our patient and others have demonstrated successful hair regrowth with dupilumab, which likely stems from a similar T_H2-related antagonism in AA.^5,6

The cause of AA is unknown, but IL-4 and IL-13 of the T_H2 pathway have been implicated, which renders support for the therapeutic effect of dupilumab in the treatment of AA. Scalp samples of patients with AA have demonstrated upregulation of T_H2, helper T-cell type 1 (T_H1), and IL-23 cytokines, suggesting efficacy with the use of anti-T_H2, anti-T_H1, and anti–IL-23 therapies.⁷ Polymerase chain reaction testing performed on serum samples in patients with AA displayed marked elevation of T_H2 cytokines, notably IL-13, which were reduced following intralesional corticosteroid treatment.⁸ It also has been demonstrated that multiple T_H2-related genes contribute to the genetic susceptibility of developing AA, specifically IL-4 and IL-13.^9,10

Prior case reports have shown contradicting effects (dupilumab-induced AA), which are speculated to be caused by a stronger T_H1 response from T_H2 suppression.^11,12 In one report, dupilumab was initiated for AD refractory to multiple topical and oral interventions. New-onset hair loss to the scalp was noted after 18 weeks of therapy. Twenty-six weeks into therapy with dupilumab, full hair regrowth was then reported.¹¹ Despite this report, our patient’s hair regrowth after the use of dupilumab for refractory AD further strengthens support for the use of dupilumab as a potential therapy for alopecia universalis and other lymphocyte-mediated hair loss conditions. However, a large disparity in response time and an overall slower progression of hair regrowth reported in our case separate it from other reports of rapid voluminous hair regrowth.^5,6 Our findings support the potential use of dupilumab in the treatment of patients with AA.

To the Editor:

Atopic diseases, specifically atopic dermatitis (AD) and alopecia areata (AA), are at the forefront of a new era in dermatology involving molecular-directed therapy. Dupilumab is one specific example, having received US Food and Drug Administration approval in March 2017 for the treatment of adults with moderate to severe AD.¹ It currently is being investigated for use in pediatric AD. The most commonly reported side effects associated with the use of dupilumab include headaches, conjunctivitis, keratitis, blepharitis, nasopharyngitis, and injection-site reactions.² We discuss a case of hair regrowth in a patient who was previously diagnosed with AA after treatment with dupilumab for refractory AD.

A 65-year-old White man presented with a history of AD since childhood. Additional medical history included hyperlipidemia; herpes simplex virus infection; asthma; and a diagnosis of AA 6 years prior, which eventually progressed to alopecia universalis. Physical examination demonstrated scattered erythematous lichenified plaques with excoriations involving the arms, legs, and trunk. The patient’s face and scalp were spared of lesions. Complete loss of body hair including the eyelashes and eyebrows also was noted, which was consistent with alopecia universalis.

The patient was started on dupilumab for refractory AD after multiple courses of topical and systemic steroids failed. Prior treatment for AD did not include immunosuppressive or light therapy. The standard dosage of dupilumab was administered, which consisted of a 600-mg subcutaneous loading dose, followed by 300 mg every 2 weeks. There was no concurrent topical corticosteroid or topical calcineurin inhibitor prescribed. After 1 month of treatment with dupilumab, near-complete resolution of the patient’s AD was noted, and after 10 months of treatment, the patient experienced regrowth of the eyelashes, terminal hairs of the beard area (Figure), and vellus hairs of the eyebrows. This hair regrowth persists today with continued dupilumab treatment, and the patient has experienced no additional side effects.

Multiple retrospective and meta-analysis studies have demonstrated a high occurrence of AD comorbid with AA, which strongly suggests a common pathogenesis.^3,4 Atopic dermatitis is an inflammatory skin disease mediated by IL-4, IL-5, and IL-13 of the helper T-cell type 2 (T_H2) pathway.¹ Dupilumab is a human monoclonal antibody that binds to IL-4Rα, which also is found in IL-13 receptors. Dupilumab prevents T_H2 pathway-related downstream signaling effects of both cytokines. Although this effect was originally utilized to suppress the T_H2-mediated signaling in AD, our patient and others have demonstrated successful hair regrowth with dupilumab, which likely stems from a similar T_H2-related antagonism in AA.^5,6

The cause of AA is unknown, but IL-4 and IL-13 of the T_H2 pathway have been implicated, which renders support for the therapeutic effect of dupilumab in the treatment of AA. Scalp samples of patients with AA have demonstrated upregulation of T_H2, helper T-cell type 1 (T_H1), and IL-23 cytokines, suggesting efficacy with the use of anti-T_H2, anti-T_H1, and anti–IL-23 therapies.⁷ Polymerase chain reaction testing performed on serum samples in patients with AA displayed marked elevation of T_H2 cytokines, notably IL-13, which were reduced following intralesional corticosteroid treatment.⁸ It also has been demonstrated that multiple T_H2-related genes contribute to the genetic susceptibility of developing AA, specifically IL-4 and IL-13.^9,10

Prior case reports have shown contradicting effects (dupilumab-induced AA), which are speculated to be caused by a stronger T_H1 response from T_H2 suppression.^11,12 In one report, dupilumab was initiated for AD refractory to multiple topical and oral interventions. New-onset hair loss to the scalp was noted after 18 weeks of therapy. Twenty-six weeks into therapy with dupilumab, full hair regrowth was then reported.¹¹ Despite this report, our patient’s hair regrowth after the use of dupilumab for refractory AD further strengthens support for the use of dupilumab as a potential therapy for alopecia universalis and other lymphocyte-mediated hair loss conditions. However, a large disparity in response time and an overall slower progression of hair regrowth reported in our case separate it from other reports of rapid voluminous hair regrowth.^5,6 Our findings support the potential use of dupilumab in the treatment of patients with AA.

To the Editor:

The Moderna COVID-19 messenger RNA (mRNA) vaccine was authorized for use on December 18, 2020, with the second dose beginning on January 15, 2021.^1-3 Some individuals who received the Moderna vaccine experienced an intense rash known as “COVID arm,” a harmless but bothersome adverse effect that typically appears within a week and is a localized and transient immunogenic response.⁴ COVID arm differs from most vaccine adverse effects. The rash emerges not immediately but 5 to 9 days after the initial dose—on average, 1 week later. Apart from being itchy, the rash does not appear to be harmful and is not a reason to hesitate getting vaccinated.

Dermatologists and allergists have been studying this adverse effect, which has been formally termed delayed cutaneous hypersensitivity. Of potential clinical consequence is that the efficacy of the mRNA COVID-19 vaccine may be harmed if postvaccination dermal reactions necessitate systemic corticosteroid therapy. Because this vaccine stimulates an immune response as viral RNA integrates in cells secondary to production of the spike protein of the virus, the skin may be affected secondarily and manifestations of any underlying disease may be aggravated.⁵ We report a patient who developed a psoriasiform dermatitis after the first dose of the Moderna vaccine.

A 65-year-old woman presented to her primary care physician because of the severity of psoriasiform dermatitis that developed 5 days after she received the first dose of the Moderna COVID-19 mRNA vaccine. The patient had a medical history of Sjögren syndrome. Her medication history was negative, and her family history was negative for autoimmune disease. Physical examination by primary care revealed an erythematous scaly rash with plaques and papules on the neck and back (Figure 1). The patient presented again to primary care 2 days later with swollen, painful, discolored digits (Figure 2) and a stiff, sore neck.

Laboratory results were positive for anti–Sjögren syndrome–related antigens A and B. A complete blood cell count; comprehensive metabolic panel; erythrocyte sedimentation rate; and assays of rheumatoid factor, C-reactive protein, and anti–cyclic citrullinated peptide were within reference range. A biopsy of a lesion on the back showed psoriasiform dermatitis with confluent parakeratosis and scattered necrotic keratinocytes. There was superficial perivascular inflammation with rare eosinophils (Figure 3).

The patient was treated with a course of systemic corticosteroids. The rash resolved in 1 week. She did not receive the second dose due to the rash.

Two mRNA COVID-19 vaccines—Pfizer BioNTech and Moderna—have been granted emergency use authorization by the US Food and Drug Administration.⁶ The safety profile of the mRNA-1273 vaccine for the median 2-month follow-up showed no safety concerns.³ Minor localized adverse effects (eg, pain, redness, swelling) have been observed more frequently with the vaccines than with placebo. Systemic symptoms, such as fever, fatigue, headache, and muscle and joint pain, also were seen somewhat more often with the vaccines than with placebo; most such effects occurred 24 to 48 hours after vaccination.^3,6,7 The frequency of unsolicited adverse events and serious adverse events reported during the 28-day period after vaccination generally was similar among participants in the vaccine and placebo groups.³

There are 2 types of reactions to COVID-19 vaccination: immediate and delayed. Immediate reactions usually are due to anaphylaxis, requiring prompt recognition and treatment with epinephrine to stop rapid progression of life-threatening symptoms. Delayed reactions include localized reactions, such as urticaria and benign exanthema; serum sickness and serum sickness–like reactions; fever; and rare skin, organ, and neurologic sequelae.^1,6-8

Cutaneous manifestations, present in 16% to 50% of patients with Sjögren syndrome, are considered one of the most common extraglandular presentations of the syndrome. They are classified as nonvascular (eg, xerosis, angular cheilitis, eyelid dermatitis, annular erythema) and vascular (eg, Raynaud phenomenon, vasculitis).^9-11 Our patient did not have any of those findings. She had not taken any medications before the rash appeared, thereby ruling out a drug reaction.

The differential for our patient included post–urinary tract infection immune-reactive arthritis and rash, which is not typical with Escherichia coli infection but is described with infection with Chlamydia species and Salmonella species. Moreover, post–urinary tract infection immune-reactive arthritis and rash appear mostly on the palms and soles. Systemic lupus erythematosus–like rashes have a different histology and appear on sun-exposed areas; our patient’s rash was found mainly on unexposed areas.¹²

Because our patient received the Moderna vaccine 5 days before the rash appeared and later developed swelling of the digits with morning stiffness, a delayed serum sickness–like reaction secondary to COVID-19 vaccination was possible.^3,6

COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna incorporate a lipid-based nanoparticle carrier system that prevents rapid enzymatic degradation of mRNA and facilitates in vivo delivery of mRNA. This lipid-based nanoparticle carrier system is further stabilized by a polyethylene glycol 2000 lipid conjugate that provides a hydrophilic layer, thus prolonging half-life. The presence of lipid polyethylene glycol 2000 in mRNA vaccines has led to concern that this component could be implicated in anaphylaxis.⁶

COVID-19 antigens can give rise to varying clinical manifestations that are directly related to viral tissue damage or are indirectly induced by the antiviral immune response.^13,14 Hyperactivation of the immune system to eradicate COVID-19 may trigger autoimmunity; several immune-mediated disorders have been described in individuals infected with SARS-CoV-2. Dermal manifestations include cutaneous rash and vasculitis.^13-16 Crucial immunologic steps occur during SARS-CoV-2 infection that may link autoimmunity to COVID-19.^13,14 In preliminary published data on the efficacy of the Moderna vaccine on 45 trial enrollees, 3 did not receive the second dose of vaccination, including 1 who developed urticaria on both legs 5 days after the first dose.¹

Introduction of viral RNA can induce autoimmunity that can be explained by various phenomena, including epitope spreading, molecular mimicry, cryptic antigen, and bystander activation. Remarkably, more than one-third of immunogenic proteins in SARS-CoV-2 have potentially problematic homology to proteins that are key to the human adaptive immune system.⁵

Moreover, SARS-CoV-2 seems to induce organ injury through alternative mechanisms beyond direct viral infection, including immunologic injury. In some situations, hyperactivation of the immune response to SARS-CoV-2 RNA can result in autoimmune disease. COVID-19 has been associated with immune-mediated systemic or organ-selective manifestations, some of which fulfill the diagnostic or classification criteria of specific autoimmune diseases. It is unclear whether those medical disorders are the result of transitory postinfectious epiphenomena.⁵

A few studies have shown that patients with rheumatic disease have an incidence and prevalence of COVID-19 that is similar to the general population. A similar pattern has been detected in COVID-19 morbidity and mortality rates, even among patients with an autoimmune disease, such as rheumatoid arthritis and Sjögren syndrome.^5,17 Furthermore, exacerbation of preexisting rheumatic symptoms may be due to hyperactivation of antiviral pathways in a person with an autoimmune disease.^17-19 The findings in our patient suggested a direct role for the vaccine in skin manifestations, rather than for reactivation or development of new systemic autoimmune processes, such as systemic lupus erythematosus.

Exacerbation of psoriasis following COVID-19 vaccination has been described²⁰; however, the case patient did not have a history of psoriasis. The mechanism(s) of such exacerbation remain unclear; COVID-19 vaccine–induced helper T cells (T_H17) may play a role.²¹ Other skin manifestations encountered following COVID-19 vaccination include lichen planus, leukocytoclastic vasculitic rash, erythema multiforme–like rash, and pityriasis rosea–like rash.^22-25 The immune mechanisms of these manifestations remain unclear.

The clinical presentation of delayed vaccination reactions can be attributed to the timing of symptoms and, in this case, the immune-mediated background of a psoriasiform reaction. Although adverse reactions to the SARS-CoV-2 mRNA vaccine are rare, more individuals should be studied after vaccination to confirm and better understand this phenomenon.

To the Editor:

The Moderna COVID-19 messenger RNA (mRNA) vaccine was authorized for use on December 18, 2020, with the second dose beginning on January 15, 2021.^1-3 Some individuals who received the Moderna vaccine experienced an intense rash known as “COVID arm,” a harmless but bothersome adverse effect that typically appears within a week and is a localized and transient immunogenic response.⁴ COVID arm differs from most vaccine adverse effects. The rash emerges not immediately but 5 to 9 days after the initial dose—on average, 1 week later. Apart from being itchy, the rash does not appear to be harmful and is not a reason to hesitate getting vaccinated.

Dermatologists and allergists have been studying this adverse effect, which has been formally termed delayed cutaneous hypersensitivity. Of potential clinical consequence is that the efficacy of the mRNA COVID-19 vaccine may be harmed if postvaccination dermal reactions necessitate systemic corticosteroid therapy. Because this vaccine stimulates an immune response as viral RNA integrates in cells secondary to production of the spike protein of the virus, the skin may be affected secondarily and manifestations of any underlying disease may be aggravated.⁵ We report a patient who developed a psoriasiform dermatitis after the first dose of the Moderna vaccine.

A 65-year-old woman presented to her primary care physician because of the severity of psoriasiform dermatitis that developed 5 days after she received the first dose of the Moderna COVID-19 mRNA vaccine. The patient had a medical history of Sjögren syndrome. Her medication history was negative, and her family history was negative for autoimmune disease. Physical examination by primary care revealed an erythematous scaly rash with plaques and papules on the neck and back (Figure 1). The patient presented again to primary care 2 days later with swollen, painful, discolored digits (Figure 2) and a stiff, sore neck.

Laboratory results were positive for anti–Sjögren syndrome–related antigens A and B. A complete blood cell count; comprehensive metabolic panel; erythrocyte sedimentation rate; and assays of rheumatoid factor, C-reactive protein, and anti–cyclic citrullinated peptide were within reference range. A biopsy of a lesion on the back showed psoriasiform dermatitis with confluent parakeratosis and scattered necrotic keratinocytes. There was superficial perivascular inflammation with rare eosinophils (Figure 3).

The patient was treated with a course of systemic corticosteroids. The rash resolved in 1 week. She did not receive the second dose due to the rash.

Two mRNA COVID-19 vaccines—Pfizer BioNTech and Moderna—have been granted emergency use authorization by the US Food and Drug Administration.⁶ The safety profile of the mRNA-1273 vaccine for the median 2-month follow-up showed no safety concerns.³ Minor localized adverse effects (eg, pain, redness, swelling) have been observed more frequently with the vaccines than with placebo. Systemic symptoms, such as fever, fatigue, headache, and muscle and joint pain, also were seen somewhat more often with the vaccines than with placebo; most such effects occurred 24 to 48 hours after vaccination.^3,6,7 The frequency of unsolicited adverse events and serious adverse events reported during the 28-day period after vaccination generally was similar among participants in the vaccine and placebo groups.³

There are 2 types of reactions to COVID-19 vaccination: immediate and delayed. Immediate reactions usually are due to anaphylaxis, requiring prompt recognition and treatment with epinephrine to stop rapid progression of life-threatening symptoms. Delayed reactions include localized reactions, such as urticaria and benign exanthema; serum sickness and serum sickness–like reactions; fever; and rare skin, organ, and neurologic sequelae.^1,6-8

Cutaneous manifestations, present in 16% to 50% of patients with Sjögren syndrome, are considered one of the most common extraglandular presentations of the syndrome. They are classified as nonvascular (eg, xerosis, angular cheilitis, eyelid dermatitis, annular erythema) and vascular (eg, Raynaud phenomenon, vasculitis).^9-11 Our patient did not have any of those findings. She had not taken any medications before the rash appeared, thereby ruling out a drug reaction.

The differential for our patient included post–urinary tract infection immune-reactive arthritis and rash, which is not typical with Escherichia coli infection but is described with infection with Chlamydia species and Salmonella species. Moreover, post–urinary tract infection immune-reactive arthritis and rash appear mostly on the palms and soles. Systemic lupus erythematosus–like rashes have a different histology and appear on sun-exposed areas; our patient’s rash was found mainly on unexposed areas.¹²

Because our patient received the Moderna vaccine 5 days before the rash appeared and later developed swelling of the digits with morning stiffness, a delayed serum sickness–like reaction secondary to COVID-19 vaccination was possible.^3,6

COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna incorporate a lipid-based nanoparticle carrier system that prevents rapid enzymatic degradation of mRNA and facilitates in vivo delivery of mRNA. This lipid-based nanoparticle carrier system is further stabilized by a polyethylene glycol 2000 lipid conjugate that provides a hydrophilic layer, thus prolonging half-life. The presence of lipid polyethylene glycol 2000 in mRNA vaccines has led to concern that this component could be implicated in anaphylaxis.⁶

COVID-19 antigens can give rise to varying clinical manifestations that are directly related to viral tissue damage or are indirectly induced by the antiviral immune response.^13,14 Hyperactivation of the immune system to eradicate COVID-19 may trigger autoimmunity; several immune-mediated disorders have been described in individuals infected with SARS-CoV-2. Dermal manifestations include cutaneous rash and vasculitis.^13-16 Crucial immunologic steps occur during SARS-CoV-2 infection that may link autoimmunity to COVID-19.^13,14 In preliminary published data on the efficacy of the Moderna vaccine on 45 trial enrollees, 3 did not receive the second dose of vaccination, including 1 who developed urticaria on both legs 5 days after the first dose.¹

Introduction of viral RNA can induce autoimmunity that can be explained by various phenomena, including epitope spreading, molecular mimicry, cryptic antigen, and bystander activation. Remarkably, more than one-third of immunogenic proteins in SARS-CoV-2 have potentially problematic homology to proteins that are key to the human adaptive immune system.⁵

Moreover, SARS-CoV-2 seems to induce organ injury through alternative mechanisms beyond direct viral infection, including immunologic injury. In some situations, hyperactivation of the immune response to SARS-CoV-2 RNA can result in autoimmune disease. COVID-19 has been associated with immune-mediated systemic or organ-selective manifestations, some of which fulfill the diagnostic or classification criteria of specific autoimmune diseases. It is unclear whether those medical disorders are the result of transitory postinfectious epiphenomena.⁵

A few studies have shown that patients with rheumatic disease have an incidence and prevalence of COVID-19 that is similar to the general population. A similar pattern has been detected in COVID-19 morbidity and mortality rates, even among patients with an autoimmune disease, such as rheumatoid arthritis and Sjögren syndrome.^5,17 Furthermore, exacerbation of preexisting rheumatic symptoms may be due to hyperactivation of antiviral pathways in a person with an autoimmune disease.^17-19 The findings in our patient suggested a direct role for the vaccine in skin manifestations, rather than for reactivation or development of new systemic autoimmune processes, such as systemic lupus erythematosus.

Exacerbation of psoriasis following COVID-19 vaccination has been described²⁰; however, the case patient did not have a history of psoriasis. The mechanism(s) of such exacerbation remain unclear; COVID-19 vaccine–induced helper T cells (T_H17) may play a role.²¹ Other skin manifestations encountered following COVID-19 vaccination include lichen planus, leukocytoclastic vasculitic rash, erythema multiforme–like rash, and pityriasis rosea–like rash.^22-25 The immune mechanisms of these manifestations remain unclear.

The clinical presentation of delayed vaccination reactions can be attributed to the timing of symptoms and, in this case, the immune-mediated background of a psoriasiform reaction. Although adverse reactions to the SARS-CoV-2 mRNA vaccine are rare, more individuals should be studied after vaccination to confirm and better understand this phenomenon.

To the Editor:

The Moderna COVID-19 messenger RNA (mRNA) vaccine was authorized for use on December 18, 2020, with the second dose beginning on January 15, 2021.^1-3 Some individuals who received the Moderna vaccine experienced an intense rash known as “COVID arm,” a harmless but bothersome adverse effect that typically appears within a week and is a localized and transient immunogenic response.⁴ COVID arm differs from most vaccine adverse effects. The rash emerges not immediately but 5 to 9 days after the initial dose—on average, 1 week later. Apart from being itchy, the rash does not appear to be harmful and is not a reason to hesitate getting vaccinated.

Dermatologists and allergists have been studying this adverse effect, which has been formally termed delayed cutaneous hypersensitivity. Of potential clinical consequence is that the efficacy of the mRNA COVID-19 vaccine may be harmed if postvaccination dermal reactions necessitate systemic corticosteroid therapy. Because this vaccine stimulates an immune response as viral RNA integrates in cells secondary to production of the spike protein of the virus, the skin may be affected secondarily and manifestations of any underlying disease may be aggravated.⁵ We report a patient who developed a psoriasiform dermatitis after the first dose of the Moderna vaccine.

A 65-year-old woman presented to her primary care physician because of the severity of psoriasiform dermatitis that developed 5 days after she received the first dose of the Moderna COVID-19 mRNA vaccine. The patient had a medical history of Sjögren syndrome. Her medication history was negative, and her family history was negative for autoimmune disease. Physical examination by primary care revealed an erythematous scaly rash with plaques and papules on the neck and back (Figure 1). The patient presented again to primary care 2 days later with swollen, painful, discolored digits (Figure 2) and a stiff, sore neck.

Laboratory results were positive for anti–Sjögren syndrome–related antigens A and B. A complete blood cell count; comprehensive metabolic panel; erythrocyte sedimentation rate; and assays of rheumatoid factor, C-reactive protein, and anti–cyclic citrullinated peptide were within reference range. A biopsy of a lesion on the back showed psoriasiform dermatitis with confluent parakeratosis and scattered necrotic keratinocytes. There was superficial perivascular inflammation with rare eosinophils (Figure 3).

The patient was treated with a course of systemic corticosteroids. The rash resolved in 1 week. She did not receive the second dose due to the rash.

Two mRNA COVID-19 vaccines—Pfizer BioNTech and Moderna—have been granted emergency use authorization by the US Food and Drug Administration.⁶ The safety profile of the mRNA-1273 vaccine for the median 2-month follow-up showed no safety concerns.³ Minor localized adverse effects (eg, pain, redness, swelling) have been observed more frequently with the vaccines than with placebo. Systemic symptoms, such as fever, fatigue, headache, and muscle and joint pain, also were seen somewhat more often with the vaccines than with placebo; most such effects occurred 24 to 48 hours after vaccination.^3,6,7 The frequency of unsolicited adverse events and serious adverse events reported during the 28-day period after vaccination generally was similar among participants in the vaccine and placebo groups.³

There are 2 types of reactions to COVID-19 vaccination: immediate and delayed. Immediate reactions usually are due to anaphylaxis, requiring prompt recognition and treatment with epinephrine to stop rapid progression of life-threatening symptoms. Delayed reactions include localized reactions, such as urticaria and benign exanthema; serum sickness and serum sickness–like reactions; fever; and rare skin, organ, and neurologic sequelae.^1,6-8

Cutaneous manifestations, present in 16% to 50% of patients with Sjögren syndrome, are considered one of the most common extraglandular presentations of the syndrome. They are classified as nonvascular (eg, xerosis, angular cheilitis, eyelid dermatitis, annular erythema) and vascular (eg, Raynaud phenomenon, vasculitis).^9-11 Our patient did not have any of those findings. She had not taken any medications before the rash appeared, thereby ruling out a drug reaction.

The differential for our patient included post–urinary tract infection immune-reactive arthritis and rash, which is not typical with Escherichia coli infection but is described with infection with Chlamydia species and Salmonella species. Moreover, post–urinary tract infection immune-reactive arthritis and rash appear mostly on the palms and soles. Systemic lupus erythematosus–like rashes have a different histology and appear on sun-exposed areas; our patient’s rash was found mainly on unexposed areas.¹²

Because our patient received the Moderna vaccine 5 days before the rash appeared and later developed swelling of the digits with morning stiffness, a delayed serum sickness–like reaction secondary to COVID-19 vaccination was possible.^3,6

COVID-19 mRNA vaccines developed by Pfizer-BioNTech and Moderna incorporate a lipid-based nanoparticle carrier system that prevents rapid enzymatic degradation of mRNA and facilitates in vivo delivery of mRNA. This lipid-based nanoparticle carrier system is further stabilized by a polyethylene glycol 2000 lipid conjugate that provides a hydrophilic layer, thus prolonging half-life. The presence of lipid polyethylene glycol 2000 in mRNA vaccines has led to concern that this component could be implicated in anaphylaxis.⁶

COVID-19 antigens can give rise to varying clinical manifestations that are directly related to viral tissue damage or are indirectly induced by the antiviral immune response.^13,14 Hyperactivation of the immune system to eradicate COVID-19 may trigger autoimmunity; several immune-mediated disorders have been described in individuals infected with SARS-CoV-2. Dermal manifestations include cutaneous rash and vasculitis.^13-16 Crucial immunologic steps occur during SARS-CoV-2 infection that may link autoimmunity to COVID-19.^13,14 In preliminary published data on the efficacy of the Moderna vaccine on 45 trial enrollees, 3 did not receive the second dose of vaccination, including 1 who developed urticaria on both legs 5 days after the first dose.¹

Introduction of viral RNA can induce autoimmunity that can be explained by various phenomena, including epitope spreading, molecular mimicry, cryptic antigen, and bystander activation. Remarkably, more than one-third of immunogenic proteins in SARS-CoV-2 have potentially problematic homology to proteins that are key to the human adaptive immune system.⁵

Moreover, SARS-CoV-2 seems to induce organ injury through alternative mechanisms beyond direct viral infection, including immunologic injury. In some situations, hyperactivation of the immune response to SARS-CoV-2 RNA can result in autoimmune disease. COVID-19 has been associated with immune-mediated systemic or organ-selective manifestations, some of which fulfill the diagnostic or classification criteria of specific autoimmune diseases. It is unclear whether those medical disorders are the result of transitory postinfectious epiphenomena.⁵

A few studies have shown that patients with rheumatic disease have an incidence and prevalence of COVID-19 that is similar to the general population. A similar pattern has been detected in COVID-19 morbidity and mortality rates, even among patients with an autoimmune disease, such as rheumatoid arthritis and Sjögren syndrome.^5,17 Furthermore, exacerbation of preexisting rheumatic symptoms may be due to hyperactivation of antiviral pathways in a person with an autoimmune disease.^17-19 The findings in our patient suggested a direct role for the vaccine in skin manifestations, rather than for reactivation or development of new systemic autoimmune processes, such as systemic lupus erythematosus.

Exacerbation of psoriasis following COVID-19 vaccination has been described²⁰; however, the case patient did not have a history of psoriasis. The mechanism(s) of such exacerbation remain unclear; COVID-19 vaccine–induced helper T cells (T_H17) may play a role.²¹ Other skin manifestations encountered following COVID-19 vaccination include lichen planus, leukocytoclastic vasculitic rash, erythema multiforme–like rash, and pityriasis rosea–like rash.^22-25 The immune mechanisms of these manifestations remain unclear.

The clinical presentation of delayed vaccination reactions can be attributed to the timing of symptoms and, in this case, the immune-mediated background of a psoriasiform reaction. Although adverse reactions to the SARS-CoV-2 mRNA vaccine are rare, more individuals should be studied after vaccination to confirm and better understand this phenomenon.

The Diagnosis: Tuberous Xanthoma

The skin biopsy revealed a nodular collection of foam cells (quiz image [bottom]). Tuberous xanthoma was the most likely diagnosis based on the patient’s history as well as the clinical and histologic findings. Tuberous xanthomas are flat or elevated nodules in the dermis and subcutaneous tissue, commonly occurring on the skin over the joints.¹ Smaller nodules and papules often are referred to as tuberoeruptive xanthomas and exist on a continuum with the larger tuberous xanthomas. All xanthomas appear histologically similar, with collections of foam cells present within the dermis.² Foam cells form when serum lipoproteins diffuse through capillary walls, deposit in the skin or tendons, and are scavenged by monocytes.3 Tuberous xanthomas, along with tendinous, eruptive, and planar xanthomas, are the most likely to be associated with hyperlipidemia.⁴ They may indicate an underlying disorder of lipid metabolism, such as familial hypercholesterolemia.^1,3 This is the most common cause of inheritable cardiovascular disease, with a prevalence of approximately 1:250.² Premature cardiovascular disease risk increases 2 to 4 times in patients with familial hypercholesterolemia and tendinous xanthomas,¹ illustrating that recognition of cutaneous lesions can lead to earlier diagnosis and prevention of patient morbidity and mortality.

Juvenile xanthogranuloma typically presents as smooth yellow papules or nodules on the head and neck, with a characteristic “setting-sun” appearance (ie, yellow center with an erythematous halo) on dermoscopy.⁵ Histologically, juvenile xanthogranulomas are composed of foam cells and a mixed lymphohistiocytic infiltrate with eosinophils within the dermis. Giant cells with a ring of nuclei surrounded by cytoplasm containing lipid vacuoles (called Touton giant cells) are characteristic (Figure 1). In contrast to tuberous xanthomas, juvenile xanthogranulomas often present within the first year of life.⁶

Keloid scars are more prevalent in patients with skin of color. They are characterized by eosinophilic keloidal collagen with a whorled proliferation of fibroblasts on histology (Figure 2).⁷ They occur spontaneously or at sites of injury and present as bluish-red or flesh-colored firm papules or nodules.⁸ In our patient, keloid scars were an unlikely diagnosis due to the lack of trauma and the absence of keloidal collagen on histology.

Necrobiosis lipoidica diabeticorum typically presents as an erythematous, yellow-brown, circular plaque on the anterior lower leg in patients with diabetes mellitus; it rarely occurs in children.⁹ Microscopy shows palisaded granulomas surrounding necrobiotic collagen arranged horizontally in a layer cake–like fashion (Figure 3).^9,10 The etiology of necrobiosis lipoidica diabeticorum currently is unknown, though immune complex deposition may contribute to its pathology. It has been associated with type 1 diabetes mellitus, though severity of the lesions is not associated with extent of glycemic control.¹⁰

Rosai-Dorfman disease is an uncommon disorder characterized by a proliferation of histiocytes that most often presents as bilateral cervical lymphadenopathy in children and young adults but rarely can present with cutaneous lesions when extranodal involvement is present.^11,12 The cutaneous form most commonly presents as red papules or nodules. On histology, the lesions exhibit a nodular dermal proliferation of histiocytes and smaller lymphocytoid cells with a marbled or starry sky–like appearance on low power (Figure 4). On higher magnification, the characteristic finding of emperipolesis can be seen.11 On immunohistochemistry, the histiocytes stain positively for CD68 and S-100. Although the pathogenesis currently is unknown, evidence of clonality indicates the disease may be related to a neoplastic process.¹²

The Diagnosis: Tuberous Xanthoma

The skin biopsy revealed a nodular collection of foam cells (quiz image [bottom]). Tuberous xanthoma was the most likely diagnosis based on the patient’s history as well as the clinical and histologic findings. Tuberous xanthomas are flat or elevated nodules in the dermis and subcutaneous tissue, commonly occurring on the skin over the joints.¹ Smaller nodules and papules often are referred to as tuberoeruptive xanthomas and exist on a continuum with the larger tuberous xanthomas. All xanthomas appear histologically similar, with collections of foam cells present within the dermis.² Foam cells form when serum lipoproteins diffuse through capillary walls, deposit in the skin or tendons, and are scavenged by monocytes.3 Tuberous xanthomas, along with tendinous, eruptive, and planar xanthomas, are the most likely to be associated with hyperlipidemia.⁴ They may indicate an underlying disorder of lipid metabolism, such as familial hypercholesterolemia.^1,3 This is the most common cause of inheritable cardiovascular disease, with a prevalence of approximately 1:250.² Premature cardiovascular disease risk increases 2 to 4 times in patients with familial hypercholesterolemia and tendinous xanthomas,¹ illustrating that recognition of cutaneous lesions can lead to earlier diagnosis and prevention of patient morbidity and mortality.

Juvenile xanthogranuloma typically presents as smooth yellow papules or nodules on the head and neck, with a characteristic “setting-sun” appearance (ie, yellow center with an erythematous halo) on dermoscopy.⁵ Histologically, juvenile xanthogranulomas are composed of foam cells and a mixed lymphohistiocytic infiltrate with eosinophils within the dermis. Giant cells with a ring of nuclei surrounded by cytoplasm containing lipid vacuoles (called Touton giant cells) are characteristic (Figure 1). In contrast to tuberous xanthomas, juvenile xanthogranulomas often present within the first year of life.⁶

Keloid scars are more prevalent in patients with skin of color. They are characterized by eosinophilic keloidal collagen with a whorled proliferation of fibroblasts on histology (Figure 2).⁷ They occur spontaneously or at sites of injury and present as bluish-red or flesh-colored firm papules or nodules.⁸ In our patient, keloid scars were an unlikely diagnosis due to the lack of trauma and the absence of keloidal collagen on histology.

Necrobiosis lipoidica diabeticorum typically presents as an erythematous, yellow-brown, circular plaque on the anterior lower leg in patients with diabetes mellitus; it rarely occurs in children.⁹ Microscopy shows palisaded granulomas surrounding necrobiotic collagen arranged horizontally in a layer cake–like fashion (Figure 3).^9,10 The etiology of necrobiosis lipoidica diabeticorum currently is unknown, though immune complex deposition may contribute to its pathology. It has been associated with type 1 diabetes mellitus, though severity of the lesions is not associated with extent of glycemic control.¹⁰

Rosai-Dorfman disease is an uncommon disorder characterized by a proliferation of histiocytes that most often presents as bilateral cervical lymphadenopathy in children and young adults but rarely can present with cutaneous lesions when extranodal involvement is present.^11,12 The cutaneous form most commonly presents as red papules or nodules. On histology, the lesions exhibit a nodular dermal proliferation of histiocytes and smaller lymphocytoid cells with a marbled or starry sky–like appearance on low power (Figure 4). On higher magnification, the characteristic finding of emperipolesis can be seen.11 On immunohistochemistry, the histiocytes stain positively for CD68 and S-100. Although the pathogenesis currently is unknown, evidence of clonality indicates the disease may be related to a neoplastic process.¹²

The Diagnosis: Tuberous Xanthoma

The skin biopsy revealed a nodular collection of foam cells (quiz image [bottom]). Tuberous xanthoma was the most likely diagnosis based on the patient’s history as well as the clinical and histologic findings. Tuberous xanthomas are flat or elevated nodules in the dermis and subcutaneous tissue, commonly occurring on the skin over the joints.¹ Smaller nodules and papules often are referred to as tuberoeruptive xanthomas and exist on a continuum with the larger tuberous xanthomas. All xanthomas appear histologically similar, with collections of foam cells present within the dermis.² Foam cells form when serum lipoproteins diffuse through capillary walls, deposit in the skin or tendons, and are scavenged by monocytes.3 Tuberous xanthomas, along with tendinous, eruptive, and planar xanthomas, are the most likely to be associated with hyperlipidemia.⁴ They may indicate an underlying disorder of lipid metabolism, such as familial hypercholesterolemia.^1,3 This is the most common cause of inheritable cardiovascular disease, with a prevalence of approximately 1:250.² Premature cardiovascular disease risk increases 2 to 4 times in patients with familial hypercholesterolemia and tendinous xanthomas,¹ illustrating that recognition of cutaneous lesions can lead to earlier diagnosis and prevention of patient morbidity and mortality.

Juvenile xanthogranuloma typically presents as smooth yellow papules or nodules on the head and neck, with a characteristic “setting-sun” appearance (ie, yellow center with an erythematous halo) on dermoscopy.⁵ Histologically, juvenile xanthogranulomas are composed of foam cells and a mixed lymphohistiocytic infiltrate with eosinophils within the dermis. Giant cells with a ring of nuclei surrounded by cytoplasm containing lipid vacuoles (called Touton giant cells) are characteristic (Figure 1). In contrast to tuberous xanthomas, juvenile xanthogranulomas often present within the first year of life.⁶

Keloid scars are more prevalent in patients with skin of color. They are characterized by eosinophilic keloidal collagen with a whorled proliferation of fibroblasts on histology (Figure 2).⁷ They occur spontaneously or at sites of injury and present as bluish-red or flesh-colored firm papules or nodules.⁸ In our patient, keloid scars were an unlikely diagnosis due to the lack of trauma and the absence of keloidal collagen on histology.

Necrobiosis lipoidica diabeticorum typically presents as an erythematous, yellow-brown, circular plaque on the anterior lower leg in patients with diabetes mellitus; it rarely occurs in children.⁹ Microscopy shows palisaded granulomas surrounding necrobiotic collagen arranged horizontally in a layer cake–like fashion (Figure 3).^9,10 The etiology of necrobiosis lipoidica diabeticorum currently is unknown, though immune complex deposition may contribute to its pathology. It has been associated with type 1 diabetes mellitus, though severity of the lesions is not associated with extent of glycemic control.¹⁰

Rosai-Dorfman disease is an uncommon disorder characterized by a proliferation of histiocytes that most often presents as bilateral cervical lymphadenopathy in children and young adults but rarely can present with cutaneous lesions when extranodal involvement is present.^11,12 The cutaneous form most commonly presents as red papules or nodules. On histology, the lesions exhibit a nodular dermal proliferation of histiocytes and smaller lymphocytoid cells with a marbled or starry sky–like appearance on low power (Figure 4). On higher magnification, the characteristic finding of emperipolesis can be seen.11 On immunohistochemistry, the histiocytes stain positively for CD68 and S-100. Although the pathogenesis currently is unknown, evidence of clonality indicates the disease may be related to a neoplastic process.¹²