Contact Dermatitis

To the Editor:

In 1998, 2-octyl-cyanoacrylate (2-CA) tissue adhesive gained US Food and Drug Administration approval for topical application to easily hold closed approximated skin edges from surgical excisions and simple trauma-induced lacerations.¹ It has since been employed for a number of off-label indications, including sutureless circumcision,² skin graft fixation,³ pericatheter leakage,⁴ and intracorporeal use to control air leaks during lung resection.⁵ Animal investigations additionally have attempted to elucidate potential future uses of 2-CA for procedures such as inguinal hernia repair,⁶ bowel anastomosis,⁷ incisional hernia repair with mesh,⁸ and microvascular anastomosis.⁹ Compared to sutures, 2-CA offers ease and rapidity of application, a water-resistant barrier, and equivalent cosmetic results, as well as eliminates the need for suture removal.¹⁰ As 2-CA is used with increasing frequency across a variety of settings, there arises a greater need to be mindful of the potential complications of its use, such as irritant contact dermatitis (ICD), allergic contact dermatitis (ACD), and cutaneous id reaction.

A 14-year-old adolescent boy with no notable medical history and no known allergies underwent a minimally invasive Nuss procedure¹¹ (performed by P.L.G.) for the repair of severe pectus excavatum. Two 4-cm incisions were made—one in each lateral chest wall at the approximately eighth intercostal space—to facilitate the introduction of the Nuss bar. The surgical wounds were closed with 2 layers of running polyglactin 910 suture before 2-CA was applied topically to the incision sites. The surgery was well tolerated, and the patient’s wounds healed without incident. When the patient was evaluated for Nuss bar removal 3 years later, incision sites were noted to be well healed, and he exhibited no other skin lesions. The original incision sites (bilateral chest walls) were utilized to facilitate surgical Nuss bar removal. The wounds were closed in 4 layers and 2-CA was again applied topically to the incision sites. There were no intraoperative complications; no devices, drains, or tissue implants were left in the patient at the conclusion of the procedure.

One week later, via text message and digital photographs, the patient reported intense pruritus at the bilateral chest wall incision sites, which were now surrounded by symmetric 1-cm erythematous plaques and associated sparse erythematous satellite papules (Figure 1). The patient denied any fevers, pain, swelling, or purulent discharge from the wounds. He was started on hydrocortisone cream 1% twice daily as well as oral diphenhydramine 25 mg at bedtime with initial good effect.

Allergic contact dermatitis is a type IV hypersensitivity reaction that appears after initial sensitization to an allergen followed by re-exposure. Our patient presented with symmetric erythematous plaques at the surgical incision sites 1 week after 2-CA had been applied. During this interval, sensitization to the inciting allergen occurred. The allergen is taken up by antigen-presenting cells, which then migrate to lymph nodes where they encounter naïve T lymphocytes that subsequently undergo clonal expansion to produce a cohort of T cells that are capable of recognizing the allergen. If subsequent exposure to the specific allergen takes place, an elicitation phase occurs in which primed T cells are incited to release mediators of inflammation that engender the manifestations of ACD within 24 to 72 hours.^18,20 Sensitization may be promoted by skin barrier impairments such as dermatitis or a frank wound.^12,20 In most cases, the patient is unaware that sensitization has occurred, though a primary ACD within 5 to 15 days after initial exposure to the inciting allergen rarely may be observed.¹⁸ Although our patient had 2-CA applied to his surgical wounds at 14 years of age, it was unlikely that sensitization took place at that time, as it was 1 week rather than 1 to 3 days before he experienced the cutaneous eruption associated with his second 2-CA exposure at 17 years of age.

Cyanoacrylate tissue adhesive also may cause ICD resulting from histotoxic degradation products such as formaldehyde and cyanoacetate that are capable of compromising cutaneous barrier function. Keratinocytes that have had their membranes disturbed release proinflammatory cytokines, which recruit cells of the innate immune system as well as T lymphocytes to the site of insult to facilitate the inflammatory response. The manifestations of ICD include erythema, edema, and local necrosis that can compromise wound healing.²⁰ The speed at which a given cyanoacrylate adhesive degrades is proportional to the length of its carbon side chain. Those with shorter side chains—ethyl and methyl cyanoacrylate—degrade more rapidly into formaldehyde and cyanoacetate; 2-CA possesses a longer side chain and therefore degrades more slowly, which should, in theory, lessen its potential to cause ICD.²⁰ Because it may take 7 to 14 days before 2-CA will spontaneously peel from the application site, however, its potential to evoke ICD nevertheless exists.

Treatment of ICD entails removing the irritant while concurrently working to restore the skin’s barrier with emollients. Although topical corticosteroids often are reflexively prescribed to treat rashes, some believe that their use should be avoided in cases of ICD, as their inhibitory effects on epidermal lipid synthesis may further impair the skin’s barrier.²¹ For cases of ACD, with or without an accompanying id reaction, topical corticosteroids are the mainstay of therapy. It is customary to start with a higher-potency topical steroid such as clobetasol and taper to lower-potency steroids as the patient’s condition improves. Steroid ointments are petroleum based and are capable of causing 2-CA to separate from the skin.¹⁰ As a result, they should be used with care when being applied to an area where 2-CA is maintaining dermal closure. Systemic corticosteroids may be warranted in cases with involvement of more than 20% of the body surface area and should start to provide relief within 12 to 24 hours.²² Oral antihistamines and cold water compresses can be added to help address pruritus and discomfort in both ACD and ICD.

Instances of contact dermatitis caused by 2-CA are rare, and progression to an id reaction is rarer still. Physicians should be aware of the possibility of encountering a patient that manifests one or both of these complications whenever 2-CA is employed for skin closure. Physicians who employ 2-CA for skin closure should first ask patients about prior cutaneous reactions to cyanoacrylates including 2-CA and other commonly encountered acrylate-containing products including adhesive wound dressings, dental cements and prostheses, superglue, artificial nails, and adhesives for wigs and false eyelashes. Still, many patients who exhibit acrylate-induced contact dermatitis, with or without an associated id reaction, will not attest to a history of adverse reactions; they simply may not recognize acrylate as the inciting agent. Practitioners across a range of specialties outside of dermatology—surgeons, emergency physicians, and primary care providers—should be prepared to both recognize contact dermatitis and id reaction arising from the use of 2-CA and implement a basic treatment plan that will bring the patient relief without compromising wound closure.

To the Editor:

In 1998, 2-octyl-cyanoacrylate (2-CA) tissue adhesive gained US Food and Drug Administration approval for topical application to easily hold closed approximated skin edges from surgical excisions and simple trauma-induced lacerations.¹ It has since been employed for a number of off-label indications, including sutureless circumcision,² skin graft fixation,³ pericatheter leakage,⁴ and intracorporeal use to control air leaks during lung resection.⁵ Animal investigations additionally have attempted to elucidate potential future uses of 2-CA for procedures such as inguinal hernia repair,⁶ bowel anastomosis,⁷ incisional hernia repair with mesh,⁸ and microvascular anastomosis.⁹ Compared to sutures, 2-CA offers ease and rapidity of application, a water-resistant barrier, and equivalent cosmetic results, as well as eliminates the need for suture removal.¹⁰ As 2-CA is used with increasing frequency across a variety of settings, there arises a greater need to be mindful of the potential complications of its use, such as irritant contact dermatitis (ICD), allergic contact dermatitis (ACD), and cutaneous id reaction.

A 14-year-old adolescent boy with no notable medical history and no known allergies underwent a minimally invasive Nuss procedure¹¹ (performed by P.L.G.) for the repair of severe pectus excavatum. Two 4-cm incisions were made—one in each lateral chest wall at the approximately eighth intercostal space—to facilitate the introduction of the Nuss bar. The surgical wounds were closed with 2 layers of running polyglactin 910 suture before 2-CA was applied topically to the incision sites. The surgery was well tolerated, and the patient’s wounds healed without incident. When the patient was evaluated for Nuss bar removal 3 years later, incision sites were noted to be well healed, and he exhibited no other skin lesions. The original incision sites (bilateral chest walls) were utilized to facilitate surgical Nuss bar removal. The wounds were closed in 4 layers and 2-CA was again applied topically to the incision sites. There were no intraoperative complications; no devices, drains, or tissue implants were left in the patient at the conclusion of the procedure.

One week later, via text message and digital photographs, the patient reported intense pruritus at the bilateral chest wall incision sites, which were now surrounded by symmetric 1-cm erythematous plaques and associated sparse erythematous satellite papules (Figure 1). The patient denied any fevers, pain, swelling, or purulent discharge from the wounds. He was started on hydrocortisone cream 1% twice daily as well as oral diphenhydramine 25 mg at bedtime with initial good effect.

Allergic contact dermatitis is a type IV hypersensitivity reaction that appears after initial sensitization to an allergen followed by re-exposure. Our patient presented with symmetric erythematous plaques at the surgical incision sites 1 week after 2-CA had been applied. During this interval, sensitization to the inciting allergen occurred. The allergen is taken up by antigen-presenting cells, which then migrate to lymph nodes where they encounter naïve T lymphocytes that subsequently undergo clonal expansion to produce a cohort of T cells that are capable of recognizing the allergen. If subsequent exposure to the specific allergen takes place, an elicitation phase occurs in which primed T cells are incited to release mediators of inflammation that engender the manifestations of ACD within 24 to 72 hours.^18,20 Sensitization may be promoted by skin barrier impairments such as dermatitis or a frank wound.^12,20 In most cases, the patient is unaware that sensitization has occurred, though a primary ACD within 5 to 15 days after initial exposure to the inciting allergen rarely may be observed.¹⁸ Although our patient had 2-CA applied to his surgical wounds at 14 years of age, it was unlikely that sensitization took place at that time, as it was 1 week rather than 1 to 3 days before he experienced the cutaneous eruption associated with his second 2-CA exposure at 17 years of age.

Cyanoacrylate tissue adhesive also may cause ICD resulting from histotoxic degradation products such as formaldehyde and cyanoacetate that are capable of compromising cutaneous barrier function. Keratinocytes that have had their membranes disturbed release proinflammatory cytokines, which recruit cells of the innate immune system as well as T lymphocytes to the site of insult to facilitate the inflammatory response. The manifestations of ICD include erythema, edema, and local necrosis that can compromise wound healing.²⁰ The speed at which a given cyanoacrylate adhesive degrades is proportional to the length of its carbon side chain. Those with shorter side chains—ethyl and methyl cyanoacrylate—degrade more rapidly into formaldehyde and cyanoacetate; 2-CA possesses a longer side chain and therefore degrades more slowly, which should, in theory, lessen its potential to cause ICD.²⁰ Because it may take 7 to 14 days before 2-CA will spontaneously peel from the application site, however, its potential to evoke ICD nevertheless exists.

Treatment of ICD entails removing the irritant while concurrently working to restore the skin’s barrier with emollients. Although topical corticosteroids often are reflexively prescribed to treat rashes, some believe that their use should be avoided in cases of ICD, as their inhibitory effects on epidermal lipid synthesis may further impair the skin’s barrier.²¹ For cases of ACD, with or without an accompanying id reaction, topical corticosteroids are the mainstay of therapy. It is customary to start with a higher-potency topical steroid such as clobetasol and taper to lower-potency steroids as the patient’s condition improves. Steroid ointments are petroleum based and are capable of causing 2-CA to separate from the skin.¹⁰ As a result, they should be used with care when being applied to an area where 2-CA is maintaining dermal closure. Systemic corticosteroids may be warranted in cases with involvement of more than 20% of the body surface area and should start to provide relief within 12 to 24 hours.²² Oral antihistamines and cold water compresses can be added to help address pruritus and discomfort in both ACD and ICD.

Instances of contact dermatitis caused by 2-CA are rare, and progression to an id reaction is rarer still. Physicians should be aware of the possibility of encountering a patient that manifests one or both of these complications whenever 2-CA is employed for skin closure. Physicians who employ 2-CA for skin closure should first ask patients about prior cutaneous reactions to cyanoacrylates including 2-CA and other commonly encountered acrylate-containing products including adhesive wound dressings, dental cements and prostheses, superglue, artificial nails, and adhesives for wigs and false eyelashes. Still, many patients who exhibit acrylate-induced contact dermatitis, with or without an associated id reaction, will not attest to a history of adverse reactions; they simply may not recognize acrylate as the inciting agent. Practitioners across a range of specialties outside of dermatology—surgeons, emergency physicians, and primary care providers—should be prepared to both recognize contact dermatitis and id reaction arising from the use of 2-CA and implement a basic treatment plan that will bring the patient relief without compromising wound closure.

To the Editor:

In 1998, 2-octyl-cyanoacrylate (2-CA) tissue adhesive gained US Food and Drug Administration approval for topical application to easily hold closed approximated skin edges from surgical excisions and simple trauma-induced lacerations.¹ It has since been employed for a number of off-label indications, including sutureless circumcision,² skin graft fixation,³ pericatheter leakage,⁴ and intracorporeal use to control air leaks during lung resection.⁵ Animal investigations additionally have attempted to elucidate potential future uses of 2-CA for procedures such as inguinal hernia repair,⁶ bowel anastomosis,⁷ incisional hernia repair with mesh,⁸ and microvascular anastomosis.⁹ Compared to sutures, 2-CA offers ease and rapidity of application, a water-resistant barrier, and equivalent cosmetic results, as well as eliminates the need for suture removal.¹⁰ As 2-CA is used with increasing frequency across a variety of settings, there arises a greater need to be mindful of the potential complications of its use, such as irritant contact dermatitis (ICD), allergic contact dermatitis (ACD), and cutaneous id reaction.

A 14-year-old adolescent boy with no notable medical history and no known allergies underwent a minimally invasive Nuss procedure¹¹ (performed by P.L.G.) for the repair of severe pectus excavatum. Two 4-cm incisions were made—one in each lateral chest wall at the approximately eighth intercostal space—to facilitate the introduction of the Nuss bar. The surgical wounds were closed with 2 layers of running polyglactin 910 suture before 2-CA was applied topically to the incision sites. The surgery was well tolerated, and the patient’s wounds healed without incident. When the patient was evaluated for Nuss bar removal 3 years later, incision sites were noted to be well healed, and he exhibited no other skin lesions. The original incision sites (bilateral chest walls) were utilized to facilitate surgical Nuss bar removal. The wounds were closed in 4 layers and 2-CA was again applied topically to the incision sites. There were no intraoperative complications; no devices, drains, or tissue implants were left in the patient at the conclusion of the procedure.

One week later, via text message and digital photographs, the patient reported intense pruritus at the bilateral chest wall incision sites, which were now surrounded by symmetric 1-cm erythematous plaques and associated sparse erythematous satellite papules (Figure 1). The patient denied any fevers, pain, swelling, or purulent discharge from the wounds. He was started on hydrocortisone cream 1% twice daily as well as oral diphenhydramine 25 mg at bedtime with initial good effect.

Allergic contact dermatitis is a type IV hypersensitivity reaction that appears after initial sensitization to an allergen followed by re-exposure. Our patient presented with symmetric erythematous plaques at the surgical incision sites 1 week after 2-CA had been applied. During this interval, sensitization to the inciting allergen occurred. The allergen is taken up by antigen-presenting cells, which then migrate to lymph nodes where they encounter naïve T lymphocytes that subsequently undergo clonal expansion to produce a cohort of T cells that are capable of recognizing the allergen. If subsequent exposure to the specific allergen takes place, an elicitation phase occurs in which primed T cells are incited to release mediators of inflammation that engender the manifestations of ACD within 24 to 72 hours.^18,20 Sensitization may be promoted by skin barrier impairments such as dermatitis or a frank wound.^12,20 In most cases, the patient is unaware that sensitization has occurred, though a primary ACD within 5 to 15 days after initial exposure to the inciting allergen rarely may be observed.¹⁸ Although our patient had 2-CA applied to his surgical wounds at 14 years of age, it was unlikely that sensitization took place at that time, as it was 1 week rather than 1 to 3 days before he experienced the cutaneous eruption associated with his second 2-CA exposure at 17 years of age.

Cyanoacrylate tissue adhesive also may cause ICD resulting from histotoxic degradation products such as formaldehyde and cyanoacetate that are capable of compromising cutaneous barrier function. Keratinocytes that have had their membranes disturbed release proinflammatory cytokines, which recruit cells of the innate immune system as well as T lymphocytes to the site of insult to facilitate the inflammatory response. The manifestations of ICD include erythema, edema, and local necrosis that can compromise wound healing.²⁰ The speed at which a given cyanoacrylate adhesive degrades is proportional to the length of its carbon side chain. Those with shorter side chains—ethyl and methyl cyanoacrylate—degrade more rapidly into formaldehyde and cyanoacetate; 2-CA possesses a longer side chain and therefore degrades more slowly, which should, in theory, lessen its potential to cause ICD.²⁰ Because it may take 7 to 14 days before 2-CA will spontaneously peel from the application site, however, its potential to evoke ICD nevertheless exists.

Treatment of ICD entails removing the irritant while concurrently working to restore the skin’s barrier with emollients. Although topical corticosteroids often are reflexively prescribed to treat rashes, some believe that their use should be avoided in cases of ICD, as their inhibitory effects on epidermal lipid synthesis may further impair the skin’s barrier.²¹ For cases of ACD, with or without an accompanying id reaction, topical corticosteroids are the mainstay of therapy. It is customary to start with a higher-potency topical steroid such as clobetasol and taper to lower-potency steroids as the patient’s condition improves. Steroid ointments are petroleum based and are capable of causing 2-CA to separate from the skin.¹⁰ As a result, they should be used with care when being applied to an area where 2-CA is maintaining dermal closure. Systemic corticosteroids may be warranted in cases with involvement of more than 20% of the body surface area and should start to provide relief within 12 to 24 hours.²² Oral antihistamines and cold water compresses can be added to help address pruritus and discomfort in both ACD and ICD.

Instances of contact dermatitis caused by 2-CA are rare, and progression to an id reaction is rarer still. Physicians should be aware of the possibility of encountering a patient that manifests one or both of these complications whenever 2-CA is employed for skin closure. Physicians who employ 2-CA for skin closure should first ask patients about prior cutaneous reactions to cyanoacrylates including 2-CA and other commonly encountered acrylate-containing products including adhesive wound dressings, dental cements and prostheses, superglue, artificial nails, and adhesives for wigs and false eyelashes. Still, many patients who exhibit acrylate-induced contact dermatitis, with or without an associated id reaction, will not attest to a history of adverse reactions; they simply may not recognize acrylate as the inciting agent. Practitioners across a range of specialties outside of dermatology—surgeons, emergency physicians, and primary care providers—should be prepared to both recognize contact dermatitis and id reaction arising from the use of 2-CA and implement a basic treatment plan that will bring the patient relief without compromising wound closure.

A variety of toys and other play products can cause contact dermatitis in children because of the nature of their ingredients, according to the results of a review of 25 published articles.

Motortion/Getty Images

“In recent years the products have become a reflection of the compounds used frequently in manufacturing, including metals and plastic compounds,” wrote Justine Fenner, MD, and coauthors, from the departments of dermatology and pediatrics at the Icahn School of Medicine at Mount Sinai, New York,

In a study published in Contact Dermatitis, the researchers identified 25 articles describing dermatitis, rash, or eczema associated with a range of toy and play product terms including Nintendo, PlayStation, putty, glue, doll, game, car, bicycle, slime, iPad, and iPhone.

Overall, nickel was the most common allergen. Cases of nickel dermatitis were associated with laptops, videogame controllers, iPads, and cell phones. Cell phones were the most common electronics associated with contact dermatitis, which was observed on the cheek, periauricular area, and hand, as well as the breast in one case of a patient who kept her phone in her bra.

Other sources of metal allergens were identified in toy cars and costume jewelry, the researchers noted.

In addition, temporary tattoos have been associated with contact dermatitis in children, as have homemade “slime” products, which often contain not only borax or other household detergents, but also glue, shaving cream, or coloring.

However, identification of true allergic contact dermatitis from toys “requires both identification of the chemical contents of toys, which are proprietary in nature, and then epicutaneous allergy testing of these ingredients,” the researchers said.

The study findings were limited by several factors including the consideration only of English-language articles and of cases in children, which thus eliminates other potential cases, the researchers noted. However, the results suggest that dermatologists consider toys as a source of contact dermatitis in children, especially if the time to diagnosis is months to years, they said. “Additionally, it may be useful, as it was in several of the above cases, to have the patient bring in his or her favorite toys for the dermatologist to examine and help further understand the etiology of patient’s rash,” they noted. Moreover, “there is an unmet need for corporations to reveal the chemical ingredients of their toys when allergic contact dermatitis is suspected in order to properly evaluate the patient,” they added.

“Contact dermatitis has been underreported in children and constitutes an ongoing concern,” senior author Nanette Silverberg, MD, chief of pediatric dermatology for the Mount Sinai Health System, said in an interview.

“In particular, toy-related allergy is concerning due to the rise in allergen inclusion in common play items,” she commented. The current analysis identified many case reports of allergens that pediatric dermatologists are frequently seeing in their offices, notably metals such as nickel, she pointed out. “The allergen that always stands out ahead of others is nickel,” Dr. Silverberg said. “Nickel allergy affects about 25% of Americans, often starting in early childhood,” she said. “In the European Union, legislation has been passed to reduce nickel release from metals, which has resulted in less sensitization to nickel. We lack such legislation in the United States,” she added. 

Other trending allergens include methylchloroisothiazolinone/methylisothiazolinone, which may be components of glue or other ingredients in some “slime” products, Dr. Silverberg said.

She advised clinicians to consider patch testing when addressing localized or persistent dermatitis in children. “Furthermore, consider toys as potential relevant allergens that should be modified in order to achieve skin improvement,” she said.

“Greater reporting of pediatric allergic contact dermatitis is needed,” Dr. Silverberg emphasized. “Additionally, surveillance and monitoring for trends in allergen exposures in toys and personal care items is required to analyze this ongoing concern of childhood,” she said.

The study received no outside funding. The researchers had no financial conflicts to disclose.

SOURCE: Fenner J et al. Contact Dermatitis. 2020 Feb 22. doi: 10.1111/cod.13500.

A variety of toys and other play products can cause contact dermatitis in children because of the nature of their ingredients, according to the results of a review of 25 published articles.

Motortion/Getty Images

“In recent years the products have become a reflection of the compounds used frequently in manufacturing, including metals and plastic compounds,” wrote Justine Fenner, MD, and coauthors, from the departments of dermatology and pediatrics at the Icahn School of Medicine at Mount Sinai, New York,

In a study published in Contact Dermatitis, the researchers identified 25 articles describing dermatitis, rash, or eczema associated with a range of toy and play product terms including Nintendo, PlayStation, putty, glue, doll, game, car, bicycle, slime, iPad, and iPhone.

Overall, nickel was the most common allergen. Cases of nickel dermatitis were associated with laptops, videogame controllers, iPads, and cell phones. Cell phones were the most common electronics associated with contact dermatitis, which was observed on the cheek, periauricular area, and hand, as well as the breast in one case of a patient who kept her phone in her bra.

Other sources of metal allergens were identified in toy cars and costume jewelry, the researchers noted.

In addition, temporary tattoos have been associated with contact dermatitis in children, as have homemade “slime” products, which often contain not only borax or other household detergents, but also glue, shaving cream, or coloring.

However, identification of true allergic contact dermatitis from toys “requires both identification of the chemical contents of toys, which are proprietary in nature, and then epicutaneous allergy testing of these ingredients,” the researchers said.

The study findings were limited by several factors including the consideration only of English-language articles and of cases in children, which thus eliminates other potential cases, the researchers noted. However, the results suggest that dermatologists consider toys as a source of contact dermatitis in children, especially if the time to diagnosis is months to years, they said. “Additionally, it may be useful, as it was in several of the above cases, to have the patient bring in his or her favorite toys for the dermatologist to examine and help further understand the etiology of patient’s rash,” they noted. Moreover, “there is an unmet need for corporations to reveal the chemical ingredients of their toys when allergic contact dermatitis is suspected in order to properly evaluate the patient,” they added.

“Contact dermatitis has been underreported in children and constitutes an ongoing concern,” senior author Nanette Silverberg, MD, chief of pediatric dermatology for the Mount Sinai Health System, said in an interview.

“In particular, toy-related allergy is concerning due to the rise in allergen inclusion in common play items,” she commented. The current analysis identified many case reports of allergens that pediatric dermatologists are frequently seeing in their offices, notably metals such as nickel, she pointed out. “The allergen that always stands out ahead of others is nickel,” Dr. Silverberg said. “Nickel allergy affects about 25% of Americans, often starting in early childhood,” she said. “In the European Union, legislation has been passed to reduce nickel release from metals, which has resulted in less sensitization to nickel. We lack such legislation in the United States,” she added. 

Other trending allergens include methylchloroisothiazolinone/methylisothiazolinone, which may be components of glue or other ingredients in some “slime” products, Dr. Silverberg said.

She advised clinicians to consider patch testing when addressing localized or persistent dermatitis in children. “Furthermore, consider toys as potential relevant allergens that should be modified in order to achieve skin improvement,” she said.

“Greater reporting of pediatric allergic contact dermatitis is needed,” Dr. Silverberg emphasized. “Additionally, surveillance and monitoring for trends in allergen exposures in toys and personal care items is required to analyze this ongoing concern of childhood,” she said.

The study received no outside funding. The researchers had no financial conflicts to disclose.

SOURCE: Fenner J et al. Contact Dermatitis. 2020 Feb 22. doi: 10.1111/cod.13500.

A variety of toys and other play products can cause contact dermatitis in children because of the nature of their ingredients, according to the results of a review of 25 published articles.

Motortion/Getty Images

“In recent years the products have become a reflection of the compounds used frequently in manufacturing, including metals and plastic compounds,” wrote Justine Fenner, MD, and coauthors, from the departments of dermatology and pediatrics at the Icahn School of Medicine at Mount Sinai, New York,

In a study published in Contact Dermatitis, the researchers identified 25 articles describing dermatitis, rash, or eczema associated with a range of toy and play product terms including Nintendo, PlayStation, putty, glue, doll, game, car, bicycle, slime, iPad, and iPhone.

Overall, nickel was the most common allergen. Cases of nickel dermatitis were associated with laptops, videogame controllers, iPads, and cell phones. Cell phones were the most common electronics associated with contact dermatitis, which was observed on the cheek, periauricular area, and hand, as well as the breast in one case of a patient who kept her phone in her bra.

Other sources of metal allergens were identified in toy cars and costume jewelry, the researchers noted.

In addition, temporary tattoos have been associated with contact dermatitis in children, as have homemade “slime” products, which often contain not only borax or other household detergents, but also glue, shaving cream, or coloring.

However, identification of true allergic contact dermatitis from toys “requires both identification of the chemical contents of toys, which are proprietary in nature, and then epicutaneous allergy testing of these ingredients,” the researchers said.

The study findings were limited by several factors including the consideration only of English-language articles and of cases in children, which thus eliminates other potential cases, the researchers noted. However, the results suggest that dermatologists consider toys as a source of contact dermatitis in children, especially if the time to diagnosis is months to years, they said. “Additionally, it may be useful, as it was in several of the above cases, to have the patient bring in his or her favorite toys for the dermatologist to examine and help further understand the etiology of patient’s rash,” they noted. Moreover, “there is an unmet need for corporations to reveal the chemical ingredients of their toys when allergic contact dermatitis is suspected in order to properly evaluate the patient,” they added.

“Contact dermatitis has been underreported in children and constitutes an ongoing concern,” senior author Nanette Silverberg, MD, chief of pediatric dermatology for the Mount Sinai Health System, said in an interview.

“In particular, toy-related allergy is concerning due to the rise in allergen inclusion in common play items,” she commented. The current analysis identified many case reports of allergens that pediatric dermatologists are frequently seeing in their offices, notably metals such as nickel, she pointed out. “The allergen that always stands out ahead of others is nickel,” Dr. Silverberg said. “Nickel allergy affects about 25% of Americans, often starting in early childhood,” she said. “In the European Union, legislation has been passed to reduce nickel release from metals, which has resulted in less sensitization to nickel. We lack such legislation in the United States,” she added. 

Other trending allergens include methylchloroisothiazolinone/methylisothiazolinone, which may be components of glue or other ingredients in some “slime” products, Dr. Silverberg said.

She advised clinicians to consider patch testing when addressing localized or persistent dermatitis in children. “Furthermore, consider toys as potential relevant allergens that should be modified in order to achieve skin improvement,” she said.

“Greater reporting of pediatric allergic contact dermatitis is needed,” Dr. Silverberg emphasized. “Additionally, surveillance and monitoring for trends in allergen exposures in toys and personal care items is required to analyze this ongoing concern of childhood,” she said.

The study received no outside funding. The researchers had no financial conflicts to disclose.

SOURCE: Fenner J et al. Contact Dermatitis. 2020 Feb 22. doi: 10.1111/cod.13500.

ORLANDO – Do you have pediatric patients with atopic dermatitis (AD) flares despite complying with treatment, or those who have a new rash in an unusual area? Consider patch testing to assess whether they have allergic contact dermatitis.

Jeff Craven/MDedge News

“Of the patients who are sent to me by local pediatric dermatologists, 50% of them are positive” for allergens, said Jonathan H. Zippin, MD, PhD, director of the contact, occupational, and photodermatitis service at Cornell University, New York.

Speaking at the ODAC Dermatology, Aesthetic, and Surgical Conference, Dr. Zippin noted the prevalence of allergen sensitization is between 13% and 25% among children who are asymptomatic, while the prevalence of sensitization to at least one allergen among children with suspected allergic contact dermatitis (ACD) is between 25% and 96%. In 2014, a study from the National American Contact Dermatitis Group (NACDG) showed that of 883 children who were patch tested, 56.7% had at least one relevant positive patch test (RPPT) result.

“The take-home message here is that pediatric contact dermatitis is common, much more common than a lot of people realize,” Dr. Zippin said.

He described three common scenarios to keep in mind: a worsening rash, a new rash, and failure of a rash to improve after the patient avoids all of his or her positive allergens.

When a rash worsens, patch testing is likely to offer answers. In an analysis of 1,142 patients with suspected ACD aged 18 years or younger (mean age, 10.5 years; 64% female) in the Pediatric Contact Dermatitis Registry study database, 65% had at least one positive patch test, and 48% had at least 1 RPPT (Dermatitis 2016; 27[5] 293-302).

But not all patch testing is the same: The study also found that 24% of the RPPT cases would have been missed if assessed with the T.R.U.E. TEST compared with extended patch testing. If a T.R.U.E. TEST fails to explain generalized atopic dermatitis, the patient should be sent for more comprehensive testing where available, Dr. Zippin advised.

Pediatric patients also have unique allergens clinicians should consider. In the same study, children had a number of allergens similar to those of adults as reported in previous studies, such as nickel, cobalt, and neomycin. However, propylene glycol and cocamidopropyl betaine were allergens identified as unique to the pediatric population.

Another study looking at the same group of patients found that compared with children who did not have AD, children with AD had 7.4 times higher odds of having an RPPT to cocamidopropyl betaine, 7.6 times higher odds of having an RPPT to parthenolide, 5.3 times higher odds of having an RPPT to tixocortol pivalate, 4.2 times higher odds of having an RPPT to wool alcohols, and 4 times higher odds of having an RPPT to lanolin (JAMA Dermatology 2017;153[8]:765-70).

All of these are components of topical medicaments used to treat AD, “either components of emollients that we recommend, or components of steroids that we recommend,” Dr. Zippin pointed out.

One of these allergens could be the culprit when a child develops a new rash but there are no new apparent changes in products, exposures, and activities. Lanolin, also called wool grease, is used in many skin care products, for example. Dr. Zippin described the case of a 6-year-old girl with a history of AD, who presented with a new rash on her scalp and behind her ears, not explained by any obvious changes to products, exposures, or activities. Subsequent patch testing determined that the rash was caused by baby shampoo, which contained cocamidopropyl betaine, which is used in hypoallergenic products. The rash resolved after a different shampoo was used.

“Sometimes, we really have to be thinking when the rash is getting worse, is there something they’re being exposed to that might be an allergen?” Dr. Zippin said.

In patients who have avoided all their positive allergens but a rash has not improved, clinicians should consider systemic contact dermatitis (SCD). Patients can develop SCD through different types of exposures, including transepidermal, transmucosal, oral, intravenous, subcutaneous, intramuscular, inhalation, and implantation routes.

SCD also has a variety of presentations, including pompholyx/dyshidrosis/vesicular dermatitis, maculopapular eruption, chronic pruritus, exfoliative erythroderma/toxiderma, chronic urticaria, erythema multiforme and vasculitis, hyperkeratotic papules of the elbows, acute generalized exanthematous pustulosis, and pruritus ani, according to Dr. Zippin.

SCD should be considered when a patient has a positive patch test to an allergen that is known to cause SCD, and does not clear after avoiding cutaneous exposure to the allergen, Dr. Zippin advised.

Patients will most often develop SCD from plants and herbs, Dr. Zippin noted. Chrysanthemums and chamomile tea are common culprits for compositae allergy and can trigger SCD; other causes are Anacardiaceae, Balsam of Peru, and propolis. Metals (nickel, cobalt, gold, and chromium), medications (aminoglycosides, corticosteroids, and ethylenediamine), and other sources (formaldehyde, propylene glycol in frozen foods, gallates, and methylisothiazolinone) can cause SCD as well.

Methylisothiazolinone in particular is a very common sensitizer, Dr. Zippin said. “If you have a patient who is positive to this, it’s almost always the cause of their problem.”

Balsam of Peru is in a number of different foods, and patients who need to follow a diet free of Balsam of Peru should avoid a long list of foods including citrus; bakery goods; Danish pastry; candy; gum; spices such as cinnamon, cloves, vanilla, curry, allspice, anise, and ginger; spicy condiments such as ketchup, chili sauce, barbecue sauce; chili, pizza, and foods with red sauces; tomatoes; pickles; alcohol (wine, beer, gin, vermouth); tea (perfumed or flavored); tobacco; chocolate and ice cream; and soft drinks (cola or spiced soft drinks).

Patients starting a nickel-free diet should avoid soy, peanuts and other nuts, legumes, chocolate, cocoa, oats, fish, and whole wheat flours. Any elimination diet should last for 3 months but should at least be tried for 3-4 weeks, with gradual reintroduction of foods suspected as triggers once per week. Any type I allergies that are discovered or suspected can be referred to an allergist for allergen challenge and desensitization therapy.

For more information, Dr. Zippin recommended the American Contact Dermatitis Society website for more information.

Dr. Zippin reported that he is the founder and holds stock options at CEP Biotech; is on the medical advisory board and receives stock options from YouV Labs., is a paid consultant and performs industry-sponsored research for Pfizer, receives stock options from Regeneron, and is on the medical advisory board for Hoth Therapeutics Inc. He is on the board of directors for the American Contact Dermatitis Society.

ORLANDO – Do you have pediatric patients with atopic dermatitis (AD) flares despite complying with treatment, or those who have a new rash in an unusual area? Consider patch testing to assess whether they have allergic contact dermatitis.

Jeff Craven/MDedge News

“Of the patients who are sent to me by local pediatric dermatologists, 50% of them are positive” for allergens, said Jonathan H. Zippin, MD, PhD, director of the contact, occupational, and photodermatitis service at Cornell University, New York.

Speaking at the ODAC Dermatology, Aesthetic, and Surgical Conference, Dr. Zippin noted the prevalence of allergen sensitization is between 13% and 25% among children who are asymptomatic, while the prevalence of sensitization to at least one allergen among children with suspected allergic contact dermatitis (ACD) is between 25% and 96%. In 2014, a study from the National American Contact Dermatitis Group (NACDG) showed that of 883 children who were patch tested, 56.7% had at least one relevant positive patch test (RPPT) result.

“The take-home message here is that pediatric contact dermatitis is common, much more common than a lot of people realize,” Dr. Zippin said.

He described three common scenarios to keep in mind: a worsening rash, a new rash, and failure of a rash to improve after the patient avoids all of his or her positive allergens.

When a rash worsens, patch testing is likely to offer answers. In an analysis of 1,142 patients with suspected ACD aged 18 years or younger (mean age, 10.5 years; 64% female) in the Pediatric Contact Dermatitis Registry study database, 65% had at least one positive patch test, and 48% had at least 1 RPPT (Dermatitis 2016; 27[5] 293-302).

But not all patch testing is the same: The study also found that 24% of the RPPT cases would have been missed if assessed with the T.R.U.E. TEST compared with extended patch testing. If a T.R.U.E. TEST fails to explain generalized atopic dermatitis, the patient should be sent for more comprehensive testing where available, Dr. Zippin advised.

Pediatric patients also have unique allergens clinicians should consider. In the same study, children had a number of allergens similar to those of adults as reported in previous studies, such as nickel, cobalt, and neomycin. However, propylene glycol and cocamidopropyl betaine were allergens identified as unique to the pediatric population.

Another study looking at the same group of patients found that compared with children who did not have AD, children with AD had 7.4 times higher odds of having an RPPT to cocamidopropyl betaine, 7.6 times higher odds of having an RPPT to parthenolide, 5.3 times higher odds of having an RPPT to tixocortol pivalate, 4.2 times higher odds of having an RPPT to wool alcohols, and 4 times higher odds of having an RPPT to lanolin (JAMA Dermatology 2017;153[8]:765-70).

All of these are components of topical medicaments used to treat AD, “either components of emollients that we recommend, or components of steroids that we recommend,” Dr. Zippin pointed out.

One of these allergens could be the culprit when a child develops a new rash but there are no new apparent changes in products, exposures, and activities. Lanolin, also called wool grease, is used in many skin care products, for example. Dr. Zippin described the case of a 6-year-old girl with a history of AD, who presented with a new rash on her scalp and behind her ears, not explained by any obvious changes to products, exposures, or activities. Subsequent patch testing determined that the rash was caused by baby shampoo, which contained cocamidopropyl betaine, which is used in hypoallergenic products. The rash resolved after a different shampoo was used.

“Sometimes, we really have to be thinking when the rash is getting worse, is there something they’re being exposed to that might be an allergen?” Dr. Zippin said.

In patients who have avoided all their positive allergens but a rash has not improved, clinicians should consider systemic contact dermatitis (SCD). Patients can develop SCD through different types of exposures, including transepidermal, transmucosal, oral, intravenous, subcutaneous, intramuscular, inhalation, and implantation routes.

SCD also has a variety of presentations, including pompholyx/dyshidrosis/vesicular dermatitis, maculopapular eruption, chronic pruritus, exfoliative erythroderma/toxiderma, chronic urticaria, erythema multiforme and vasculitis, hyperkeratotic papules of the elbows, acute generalized exanthematous pustulosis, and pruritus ani, according to Dr. Zippin.

SCD should be considered when a patient has a positive patch test to an allergen that is known to cause SCD, and does not clear after avoiding cutaneous exposure to the allergen, Dr. Zippin advised.

Patients will most often develop SCD from plants and herbs, Dr. Zippin noted. Chrysanthemums and chamomile tea are common culprits for compositae allergy and can trigger SCD; other causes are Anacardiaceae, Balsam of Peru, and propolis. Metals (nickel, cobalt, gold, and chromium), medications (aminoglycosides, corticosteroids, and ethylenediamine), and other sources (formaldehyde, propylene glycol in frozen foods, gallates, and methylisothiazolinone) can cause SCD as well.

Methylisothiazolinone in particular is a very common sensitizer, Dr. Zippin said. “If you have a patient who is positive to this, it’s almost always the cause of their problem.”

Balsam of Peru is in a number of different foods, and patients who need to follow a diet free of Balsam of Peru should avoid a long list of foods including citrus; bakery goods; Danish pastry; candy; gum; spices such as cinnamon, cloves, vanilla, curry, allspice, anise, and ginger; spicy condiments such as ketchup, chili sauce, barbecue sauce; chili, pizza, and foods with red sauces; tomatoes; pickles; alcohol (wine, beer, gin, vermouth); tea (perfumed or flavored); tobacco; chocolate and ice cream; and soft drinks (cola or spiced soft drinks).

Patients starting a nickel-free diet should avoid soy, peanuts and other nuts, legumes, chocolate, cocoa, oats, fish, and whole wheat flours. Any elimination diet should last for 3 months but should at least be tried for 3-4 weeks, with gradual reintroduction of foods suspected as triggers once per week. Any type I allergies that are discovered or suspected can be referred to an allergist for allergen challenge and desensitization therapy.

For more information, Dr. Zippin recommended the American Contact Dermatitis Society website for more information.

Dr. Zippin reported that he is the founder and holds stock options at CEP Biotech; is on the medical advisory board and receives stock options from YouV Labs., is a paid consultant and performs industry-sponsored research for Pfizer, receives stock options from Regeneron, and is on the medical advisory board for Hoth Therapeutics Inc. He is on the board of directors for the American Contact Dermatitis Society.

ORLANDO – Do you have pediatric patients with atopic dermatitis (AD) flares despite complying with treatment, or those who have a new rash in an unusual area? Consider patch testing to assess whether they have allergic contact dermatitis.

Jeff Craven/MDedge News

“Of the patients who are sent to me by local pediatric dermatologists, 50% of them are positive” for allergens, said Jonathan H. Zippin, MD, PhD, director of the contact, occupational, and photodermatitis service at Cornell University, New York.

Speaking at the ODAC Dermatology, Aesthetic, and Surgical Conference, Dr. Zippin noted the prevalence of allergen sensitization is between 13% and 25% among children who are asymptomatic, while the prevalence of sensitization to at least one allergen among children with suspected allergic contact dermatitis (ACD) is between 25% and 96%. In 2014, a study from the National American Contact Dermatitis Group (NACDG) showed that of 883 children who were patch tested, 56.7% had at least one relevant positive patch test (RPPT) result.

“The take-home message here is that pediatric contact dermatitis is common, much more common than a lot of people realize,” Dr. Zippin said.

He described three common scenarios to keep in mind: a worsening rash, a new rash, and failure of a rash to improve after the patient avoids all of his or her positive allergens.

When a rash worsens, patch testing is likely to offer answers. In an analysis of 1,142 patients with suspected ACD aged 18 years or younger (mean age, 10.5 years; 64% female) in the Pediatric Contact Dermatitis Registry study database, 65% had at least one positive patch test, and 48% had at least 1 RPPT (Dermatitis 2016; 27[5] 293-302).

But not all patch testing is the same: The study also found that 24% of the RPPT cases would have been missed if assessed with the T.R.U.E. TEST compared with extended patch testing. If a T.R.U.E. TEST fails to explain generalized atopic dermatitis, the patient should be sent for more comprehensive testing where available, Dr. Zippin advised.

Pediatric patients also have unique allergens clinicians should consider. In the same study, children had a number of allergens similar to those of adults as reported in previous studies, such as nickel, cobalt, and neomycin. However, propylene glycol and cocamidopropyl betaine were allergens identified as unique to the pediatric population.

Another study looking at the same group of patients found that compared with children who did not have AD, children with AD had 7.4 times higher odds of having an RPPT to cocamidopropyl betaine, 7.6 times higher odds of having an RPPT to parthenolide, 5.3 times higher odds of having an RPPT to tixocortol pivalate, 4.2 times higher odds of having an RPPT to wool alcohols, and 4 times higher odds of having an RPPT to lanolin (JAMA Dermatology 2017;153[8]:765-70).

All of these are components of topical medicaments used to treat AD, “either components of emollients that we recommend, or components of steroids that we recommend,” Dr. Zippin pointed out.

One of these allergens could be the culprit when a child develops a new rash but there are no new apparent changes in products, exposures, and activities. Lanolin, also called wool grease, is used in many skin care products, for example. Dr. Zippin described the case of a 6-year-old girl with a history of AD, who presented with a new rash on her scalp and behind her ears, not explained by any obvious changes to products, exposures, or activities. Subsequent patch testing determined that the rash was caused by baby shampoo, which contained cocamidopropyl betaine, which is used in hypoallergenic products. The rash resolved after a different shampoo was used.

“Sometimes, we really have to be thinking when the rash is getting worse, is there something they’re being exposed to that might be an allergen?” Dr. Zippin said.

In patients who have avoided all their positive allergens but a rash has not improved, clinicians should consider systemic contact dermatitis (SCD). Patients can develop SCD through different types of exposures, including transepidermal, transmucosal, oral, intravenous, subcutaneous, intramuscular, inhalation, and implantation routes.

SCD also has a variety of presentations, including pompholyx/dyshidrosis/vesicular dermatitis, maculopapular eruption, chronic pruritus, exfoliative erythroderma/toxiderma, chronic urticaria, erythema multiforme and vasculitis, hyperkeratotic papules of the elbows, acute generalized exanthematous pustulosis, and pruritus ani, according to Dr. Zippin.

SCD should be considered when a patient has a positive patch test to an allergen that is known to cause SCD, and does not clear after avoiding cutaneous exposure to the allergen, Dr. Zippin advised.

Patients will most often develop SCD from plants and herbs, Dr. Zippin noted. Chrysanthemums and chamomile tea are common culprits for compositae allergy and can trigger SCD; other causes are Anacardiaceae, Balsam of Peru, and propolis. Metals (nickel, cobalt, gold, and chromium), medications (aminoglycosides, corticosteroids, and ethylenediamine), and other sources (formaldehyde, propylene glycol in frozen foods, gallates, and methylisothiazolinone) can cause SCD as well.

Methylisothiazolinone in particular is a very common sensitizer, Dr. Zippin said. “If you have a patient who is positive to this, it’s almost always the cause of their problem.”

Balsam of Peru is in a number of different foods, and patients who need to follow a diet free of Balsam of Peru should avoid a long list of foods including citrus; bakery goods; Danish pastry; candy; gum; spices such as cinnamon, cloves, vanilla, curry, allspice, anise, and ginger; spicy condiments such as ketchup, chili sauce, barbecue sauce; chili, pizza, and foods with red sauces; tomatoes; pickles; alcohol (wine, beer, gin, vermouth); tea (perfumed or flavored); tobacco; chocolate and ice cream; and soft drinks (cola or spiced soft drinks).

Patients starting a nickel-free diet should avoid soy, peanuts and other nuts, legumes, chocolate, cocoa, oats, fish, and whole wheat flours. Any elimination diet should last for 3 months but should at least be tried for 3-4 weeks, with gradual reintroduction of foods suspected as triggers once per week. Any type I allergies that are discovered or suspected can be referred to an allergist for allergen challenge and desensitization therapy.

For more information, Dr. Zippin recommended the American Contact Dermatitis Society website for more information.

Dr. Zippin reported that he is the founder and holds stock options at CEP Biotech; is on the medical advisory board and receives stock options from YouV Labs., is a paid consultant and performs industry-sponsored research for Pfizer, receives stock options from Regeneron, and is on the medical advisory board for Hoth Therapeutics Inc. He is on the board of directors for the American Contact Dermatitis Society.

Hypersensitivity to metal implants remains a controversial field in contact dermatitis and patch testing. With positive reactions to nickel hovering around 20% in patch-tested populations,¹ the question remains whether metal-allergic patients can safely receive metal implants. Unfortunately, large controlled studies are lacking, in part due to ethical concerns of knowingly placing a metal implant in a metal-allergic patient. Much of the focus of implant hypersensitivity reactions (IHRs) has been on orthopedic joints including hips, knees, and shoulders, as well as fixed orthopedic implanted materials such as screws and plates. However, there have been reports of IHRs to cardiac devices including defibrillators, pacemakers, and intracardiac devices; dental hardware including implants, crowns, dentures, and braces; and neurologic and gynecologic devices. For the purposes of this review, we will focus on IHRs to orthopedic implants.

Making the Case for IHRs

There are multiple case reports and series documenting likely orthopedic IHRs in the literature^2-5; however, large prospective studies are lacking. Some of the largest series are from Danish registry studies. In 2009, Thyssen et al⁶ reviewed356 patients who had undergone both total hip arthroplasty and patch testing. Metal allergy frequencies were similar between patch-tested registry patients and patch test controls, showing no increase in positive patch tests to metals after receiving implants. Additionally, implant revision rates were comparable between registry patients with and without patch testing. The group concluded that the risk for revision after hip implantation in metal-allergic patients and the risk for development of metal allergy after implantation were both low.⁶ In 2015, Münch et al⁷ compared 327 patients who had undergone both total knee arthroplasty and patch testing and found that prevalence of allergy to nickel, cobalt, and chromium was similar between patients who had undergone revision surgery and those who had not; however, for patients who had 2 or more knee revisions, there was a higher prevalence of postimplant metal allergy. This study also showed that metal allergy identified before implantation did not increase the risk for postimplantation knee revision surgery or implant failure.⁷ These larger studies suggest that although individual cases of IHR exist, it is likely quite rare.

Patients have been found to have increased levels of chromium (serum and urine) and titanium (serum) following total hip arthroplasty.⁸ Additionally, metal wear particles have been identified in postmortem livers and spleens, which was more prevalent in patients with a history of failed hip arthroplasty.⁹ It is difficult to determine the meaning of this data, as the presence of metal ions does not necessarily indicate allergy or IHR. In 2001, Hallab et al¹⁰ pooled data from several implant cohort studies and concluded that in comparison to a baseline metal sensitivity prevalence of approximately 10%, patients with well-functioning implants had a metal sensitivity–weighted average of 25%, and those with poorly functioning implants had a weighted average of 60%. Again, positive patch testing to metals does not necessarily implicate allergy as the cause of implant failure.

Some small studies have shown that patients with evidence of metal hypersensitivity improve with revision. Zondervan et al¹¹ reviewed results of 46 orthopedic revisions following painful total knee arthroplasty. Patients with knee pain and lymphocyte transformation testing (LTT) positive for metals received hypoallergenic revisions, and those with LTT negative for metals received standard revisions. The group who received hypoallergenic revisions had more pain reduction compared to the standard revision group (37.8% reduction in pain vs 27%). However, this study was limited in that the diagnosis of metal allergy was made entirely on results of LTT.¹¹ In 2012, Atanaskova Mesinkovska et al¹² described 41 patients who underwent orthopedic patch testing following implantation for symptoms including pain, dermatitis, pruritus, joint loosening, edema, and impaired wound healing. Fifteen (37%) patients had positive patch test reactions to metals, and 10 (67%) of them had reactions to metals that were present in their implants. Six (60%) of these patients had their implants removed and their symptoms resolved; the remaining 4 continued to experience implant symptoms.¹² These studies support the existence of rare metal-related orthopedic IHRs and support the concept of proceeding with orthopedic implant revision when indicated, safe, and agreed upon by the surgeon and patient. However, as noted in the series by Zondervan et al,¹¹ not every patient with confirmed metal allergy who undergoes revision improves, so an informed conversation between the patient and surgeon is mandatory.

Types of Orthopedic Implants

Orthopedic implanted materials consist of either dynamic (knees, hips) or static (screws, plates) components. Several generations of hip implants have evolved since the 1960s. First-generation implanted hips were metal-on-metal and had high rates of metal release and sensitization. Metal-on-plastic implants may be less likely to release metal but instead release large polyethylene wear particles. Second-generation metal-on-metal implants reportedly have lower wear rates. With these implants, wear particles are generated but are reportedly smaller than first-generation particles.¹³

Allergens in IHRs

Metals
Metals are the most commonly implicated allergens in orthopedic IHRs. Potentially relevant metal alloys include 316L stainless steel, cobalt-chromium-molybdenum steel, Vitallium alloy, titanium alloy, titanium-tantalum-niobium alloy, and Oxinium (Smith & Nephew).^14,15 Each alloy contains several metals, which can include nickel, chromium, cobalt, manganese, molybdenum, iron, titanium, aluminum, vanadium, niobium, tantalum, and zirconium, among others. For example, 316L stainless steel contains iron, nickel, chromium, manganese, molybdenum, nitrogen, carbon, sulfur, silicon, and phosphorus, whereas Oxinium contains only oxidized zirconium and niobium.

Bone Cement
Bone cement also has been reported in cases of orthopedic IHRs and can contain several chemicals, including methyl methacrylate, N,N-dimethyl-p-toluidine, benzoyl peroxide, hydroquinone, and gentamicin.¹⁴ Other potential exposures include adhesives (cyanoacrylates) and topical antibiotics.

Clinical Presentation

Several clinical presentations of orthopedic IHRs have been described. Perhaps the most commonly recognized is a localized cutaneous eczematous eruption, with dermatitis typically overlying the site of the implanted material.^1,2,16 Generalized cutaneous eczematous IHRs also have been reported, including diffuse generalized dermatitis from a stainless steel orthopedic screw⁴ and nummular dermatitis attributed to vanadium in an orthopedic plate.⁵ Urticaria, vasculitis, and bullous cutaneous reactions, as well as extracutaneous complications, also have been reported.^14,15 Pain, edema, joint loosening or failure, and poor wound healing have been reported,¹² but it remains unclear whether these symptoms represent IHR.

Patch Testing for IHR

Several groups have published recommended patch test series for IHR.^12,14,15 Common components of implant patch testing panels include metals, adhesives (acrylates, epoxy resins) and antibiotics. Importantly, obtaining product information from the manufacturer of the suspected implant can guide which allergens to include in patch testing. Implant and metal panels also are available for commercial purchase.

Other Diagnostic Tests

We rarely (almost never) order LTTs in the workup for potential IHRs. This is an in vitro test that includes lymphocytes, metal ions, and the radioactive marker methyl-3H-thymidine. The goal of the test is to evaluate if patient lymphocytes are reactive or responsive to metal ions. A positive LTT suggests that lymphocytes can respond to the presence of metal ions but does not confirm allergy or the presence of IHR.

Typically, skin or tissue biopsies are not required to make a diagnosis of IHR; however, if performed, histopathology suggestive of IHR can support a suspected diagnosis. Typical findings include but are not limited to spongiotic dermatitis. Eosinophils may or may not be present. Metal disc testing has been utilized for orthopedic IHR but is not currently recommended due to low diagnostic yield. Prick testing rarely is used and also is not a primary method for diagnosis of IHR.¹⁷

Preimplantation Patch Testing

Expert opinion guidelines published by the American Contact Dermatitis Society (ACDS) state that routine preimplantation patch testing is not necessary; however, for those patients with a clear history of contact reactions to metal, preimplantation patch testing can be considered.¹⁷

Patch test results can influence the orthopedic surgeon’s choice of implant material. In one study, when preimplantation patch testing showed a positive patch test reaction to metals, the results influenced the surgeon’s decision-making in all cases.¹²

Postimplantation Patch Testing: Diagnostic Criteria for Metal IHR After Implantation

From 2012 to 2013, Schalock and Thyssen¹⁸ surveyed expert attendees at meetings of the European Society of Contact Dermatitis and the ACDS for their opinions on proposed diagnostic criteria for metal IHRs. Based on these results (N=119), the authors stratified 4 major and 5 minor diagnostic criteria, which were defined based on overall responses of meeting attendees. Major criteria included (1) chronic dermatitis beginning weeks to months after metallic implantation, (2) complete recovery after removal of the offending implant, (3) eruption overlying the metal implant, and (4) positive patch test reaction to a metal used in the implant. Minor criteria included (1) histology consistent with allergic contact dermatitis, (2) morphology consistent with dermatitis (ie, erythema, induration, papules, vesicles), (3) positive in vitro test to metals (eg, lymphocyte transformation test), (4) systemic allergic dermatitis reaction, and (5) therapy-resistant dermatitis reaction. The authors did not describe a scoring system for evaluation and confirmation of a diagnosis of IHR. Instead, the criteria should be used as general guidelines when evaluating patients for possible IHRs. From a standpoint of available diagnostic tests for metal IHR, 86.1% of experts agreed that a positive patch test reaction to a metal used in the implant was suggestive of a diagnosis, whereas a positive in vitro test to metals (LTT) was suggestive of a diagnosis for only 32.2% of respondents. This study was designed specifically for metal IHRs and therefore is not necessarily generalizable for nonmetal IHRs.¹⁸

Final Interpretation

We follow the 2016 ACDS guidelines¹⁷ and complete preimplantation patch testing only in the setting of suspected metal allergy and postimplantation patch testing based on the guidelines described by Schalock and Thyssen.¹⁸ However, an extended conversation is warranted prior to patch testing to ensure the patient fully understands the limitations of the test. Although we have both ordered the LTT, interpretation remains murky, and until this test is standardized, routine use is unlikely to benefit the patient. Until we are more reliably able to predict who will develop hypersensitivity to implanted metals, the decision to remove or revise an implant is one that should be made by a multidisciplinary team that includes the surgeon and the patient.

Hypersensitivity to metal implants remains a controversial field in contact dermatitis and patch testing. With positive reactions to nickel hovering around 20% in patch-tested populations,¹ the question remains whether metal-allergic patients can safely receive metal implants. Unfortunately, large controlled studies are lacking, in part due to ethical concerns of knowingly placing a metal implant in a metal-allergic patient. Much of the focus of implant hypersensitivity reactions (IHRs) has been on orthopedic joints including hips, knees, and shoulders, as well as fixed orthopedic implanted materials such as screws and plates. However, there have been reports of IHRs to cardiac devices including defibrillators, pacemakers, and intracardiac devices; dental hardware including implants, crowns, dentures, and braces; and neurologic and gynecologic devices. For the purposes of this review, we will focus on IHRs to orthopedic implants.

Making the Case for IHRs

There are multiple case reports and series documenting likely orthopedic IHRs in the literature^2-5; however, large prospective studies are lacking. Some of the largest series are from Danish registry studies. In 2009, Thyssen et al⁶ reviewed356 patients who had undergone both total hip arthroplasty and patch testing. Metal allergy frequencies were similar between patch-tested registry patients and patch test controls, showing no increase in positive patch tests to metals after receiving implants. Additionally, implant revision rates were comparable between registry patients with and without patch testing. The group concluded that the risk for revision after hip implantation in metal-allergic patients and the risk for development of metal allergy after implantation were both low.⁶ In 2015, Münch et al⁷ compared 327 patients who had undergone both total knee arthroplasty and patch testing and found that prevalence of allergy to nickel, cobalt, and chromium was similar between patients who had undergone revision surgery and those who had not; however, for patients who had 2 or more knee revisions, there was a higher prevalence of postimplant metal allergy. This study also showed that metal allergy identified before implantation did not increase the risk for postimplantation knee revision surgery or implant failure.⁷ These larger studies suggest that although individual cases of IHR exist, it is likely quite rare.

Patients have been found to have increased levels of chromium (serum and urine) and titanium (serum) following total hip arthroplasty.⁸ Additionally, metal wear particles have been identified in postmortem livers and spleens, which was more prevalent in patients with a history of failed hip arthroplasty.⁹ It is difficult to determine the meaning of this data, as the presence of metal ions does not necessarily indicate allergy or IHR. In 2001, Hallab et al¹⁰ pooled data from several implant cohort studies and concluded that in comparison to a baseline metal sensitivity prevalence of approximately 10%, patients with well-functioning implants had a metal sensitivity–weighted average of 25%, and those with poorly functioning implants had a weighted average of 60%. Again, positive patch testing to metals does not necessarily implicate allergy as the cause of implant failure.

Some small studies have shown that patients with evidence of metal hypersensitivity improve with revision. Zondervan et al¹¹ reviewed results of 46 orthopedic revisions following painful total knee arthroplasty. Patients with knee pain and lymphocyte transformation testing (LTT) positive for metals received hypoallergenic revisions, and those with LTT negative for metals received standard revisions. The group who received hypoallergenic revisions had more pain reduction compared to the standard revision group (37.8% reduction in pain vs 27%). However, this study was limited in that the diagnosis of metal allergy was made entirely on results of LTT.¹¹ In 2012, Atanaskova Mesinkovska et al¹² described 41 patients who underwent orthopedic patch testing following implantation for symptoms including pain, dermatitis, pruritus, joint loosening, edema, and impaired wound healing. Fifteen (37%) patients had positive patch test reactions to metals, and 10 (67%) of them had reactions to metals that were present in their implants. Six (60%) of these patients had their implants removed and their symptoms resolved; the remaining 4 continued to experience implant symptoms.¹² These studies support the existence of rare metal-related orthopedic IHRs and support the concept of proceeding with orthopedic implant revision when indicated, safe, and agreed upon by the surgeon and patient. However, as noted in the series by Zondervan et al,¹¹ not every patient with confirmed metal allergy who undergoes revision improves, so an informed conversation between the patient and surgeon is mandatory.

Types of Orthopedic Implants

Orthopedic implanted materials consist of either dynamic (knees, hips) or static (screws, plates) components. Several generations of hip implants have evolved since the 1960s. First-generation implanted hips were metal-on-metal and had high rates of metal release and sensitization. Metal-on-plastic implants may be less likely to release metal but instead release large polyethylene wear particles. Second-generation metal-on-metal implants reportedly have lower wear rates. With these implants, wear particles are generated but are reportedly smaller than first-generation particles.¹³

Allergens in IHRs

Metals
Metals are the most commonly implicated allergens in orthopedic IHRs. Potentially relevant metal alloys include 316L stainless steel, cobalt-chromium-molybdenum steel, Vitallium alloy, titanium alloy, titanium-tantalum-niobium alloy, and Oxinium (Smith & Nephew).^14,15 Each alloy contains several metals, which can include nickel, chromium, cobalt, manganese, molybdenum, iron, titanium, aluminum, vanadium, niobium, tantalum, and zirconium, among others. For example, 316L stainless steel contains iron, nickel, chromium, manganese, molybdenum, nitrogen, carbon, sulfur, silicon, and phosphorus, whereas Oxinium contains only oxidized zirconium and niobium.

Bone Cement
Bone cement also has been reported in cases of orthopedic IHRs and can contain several chemicals, including methyl methacrylate, N,N-dimethyl-p-toluidine, benzoyl peroxide, hydroquinone, and gentamicin.¹⁴ Other potential exposures include adhesives (cyanoacrylates) and topical antibiotics.

Clinical Presentation

Several clinical presentations of orthopedic IHRs have been described. Perhaps the most commonly recognized is a localized cutaneous eczematous eruption, with dermatitis typically overlying the site of the implanted material.^1,2,16 Generalized cutaneous eczematous IHRs also have been reported, including diffuse generalized dermatitis from a stainless steel orthopedic screw⁴ and nummular dermatitis attributed to vanadium in an orthopedic plate.⁵ Urticaria, vasculitis, and bullous cutaneous reactions, as well as extracutaneous complications, also have been reported.^14,15 Pain, edema, joint loosening or failure, and poor wound healing have been reported,¹² but it remains unclear whether these symptoms represent IHR.

Patch Testing for IHR

Several groups have published recommended patch test series for IHR.^12,14,15 Common components of implant patch testing panels include metals, adhesives (acrylates, epoxy resins) and antibiotics. Importantly, obtaining product information from the manufacturer of the suspected implant can guide which allergens to include in patch testing. Implant and metal panels also are available for commercial purchase.

Other Diagnostic Tests

We rarely (almost never) order LTTs in the workup for potential IHRs. This is an in vitro test that includes lymphocytes, metal ions, and the radioactive marker methyl-3H-thymidine. The goal of the test is to evaluate if patient lymphocytes are reactive or responsive to metal ions. A positive LTT suggests that lymphocytes can respond to the presence of metal ions but does not confirm allergy or the presence of IHR.

Typically, skin or tissue biopsies are not required to make a diagnosis of IHR; however, if performed, histopathology suggestive of IHR can support a suspected diagnosis. Typical findings include but are not limited to spongiotic dermatitis. Eosinophils may or may not be present. Metal disc testing has been utilized for orthopedic IHR but is not currently recommended due to low diagnostic yield. Prick testing rarely is used and also is not a primary method for diagnosis of IHR.¹⁷

Preimplantation Patch Testing

Expert opinion guidelines published by the American Contact Dermatitis Society (ACDS) state that routine preimplantation patch testing is not necessary; however, for those patients with a clear history of contact reactions to metal, preimplantation patch testing can be considered.¹⁷

Patch test results can influence the orthopedic surgeon’s choice of implant material. In one study, when preimplantation patch testing showed a positive patch test reaction to metals, the results influenced the surgeon’s decision-making in all cases.¹²

Postimplantation Patch Testing: Diagnostic Criteria for Metal IHR After Implantation

From 2012 to 2013, Schalock and Thyssen¹⁸ surveyed expert attendees at meetings of the European Society of Contact Dermatitis and the ACDS for their opinions on proposed diagnostic criteria for metal IHRs. Based on these results (N=119), the authors stratified 4 major and 5 minor diagnostic criteria, which were defined based on overall responses of meeting attendees. Major criteria included (1) chronic dermatitis beginning weeks to months after metallic implantation, (2) complete recovery after removal of the offending implant, (3) eruption overlying the metal implant, and (4) positive patch test reaction to a metal used in the implant. Minor criteria included (1) histology consistent with allergic contact dermatitis, (2) morphology consistent with dermatitis (ie, erythema, induration, papules, vesicles), (3) positive in vitro test to metals (eg, lymphocyte transformation test), (4) systemic allergic dermatitis reaction, and (5) therapy-resistant dermatitis reaction. The authors did not describe a scoring system for evaluation and confirmation of a diagnosis of IHR. Instead, the criteria should be used as general guidelines when evaluating patients for possible IHRs. From a standpoint of available diagnostic tests for metal IHR, 86.1% of experts agreed that a positive patch test reaction to a metal used in the implant was suggestive of a diagnosis, whereas a positive in vitro test to metals (LTT) was suggestive of a diagnosis for only 32.2% of respondents. This study was designed specifically for metal IHRs and therefore is not necessarily generalizable for nonmetal IHRs.¹⁸

Final Interpretation

We follow the 2016 ACDS guidelines¹⁷ and complete preimplantation patch testing only in the setting of suspected metal allergy and postimplantation patch testing based on the guidelines described by Schalock and Thyssen.¹⁸ However, an extended conversation is warranted prior to patch testing to ensure the patient fully understands the limitations of the test. Although we have both ordered the LTT, interpretation remains murky, and until this test is standardized, routine use is unlikely to benefit the patient. Until we are more reliably able to predict who will develop hypersensitivity to implanted metals, the decision to remove or revise an implant is one that should be made by a multidisciplinary team that includes the surgeon and the patient.

Hypersensitivity to metal implants remains a controversial field in contact dermatitis and patch testing. With positive reactions to nickel hovering around 20% in patch-tested populations,¹ the question remains whether metal-allergic patients can safely receive metal implants. Unfortunately, large controlled studies are lacking, in part due to ethical concerns of knowingly placing a metal implant in a metal-allergic patient. Much of the focus of implant hypersensitivity reactions (IHRs) has been on orthopedic joints including hips, knees, and shoulders, as well as fixed orthopedic implanted materials such as screws and plates. However, there have been reports of IHRs to cardiac devices including defibrillators, pacemakers, and intracardiac devices; dental hardware including implants, crowns, dentures, and braces; and neurologic and gynecologic devices. For the purposes of this review, we will focus on IHRs to orthopedic implants.

Making the Case for IHRs

There are multiple case reports and series documenting likely orthopedic IHRs in the literature^2-5; however, large prospective studies are lacking. Some of the largest series are from Danish registry studies. In 2009, Thyssen et al⁶ reviewed356 patients who had undergone both total hip arthroplasty and patch testing. Metal allergy frequencies were similar between patch-tested registry patients and patch test controls, showing no increase in positive patch tests to metals after receiving implants. Additionally, implant revision rates were comparable between registry patients with and without patch testing. The group concluded that the risk for revision after hip implantation in metal-allergic patients and the risk for development of metal allergy after implantation were both low.⁶ In 2015, Münch et al⁷ compared 327 patients who had undergone both total knee arthroplasty and patch testing and found that prevalence of allergy to nickel, cobalt, and chromium was similar between patients who had undergone revision surgery and those who had not; however, for patients who had 2 or more knee revisions, there was a higher prevalence of postimplant metal allergy. This study also showed that metal allergy identified before implantation did not increase the risk for postimplantation knee revision surgery or implant failure.⁷ These larger studies suggest that although individual cases of IHR exist, it is likely quite rare.

Patients have been found to have increased levels of chromium (serum and urine) and titanium (serum) following total hip arthroplasty.⁸ Additionally, metal wear particles have been identified in postmortem livers and spleens, which was more prevalent in patients with a history of failed hip arthroplasty.⁹ It is difficult to determine the meaning of this data, as the presence of metal ions does not necessarily indicate allergy or IHR. In 2001, Hallab et al¹⁰ pooled data from several implant cohort studies and concluded that in comparison to a baseline metal sensitivity prevalence of approximately 10%, patients with well-functioning implants had a metal sensitivity–weighted average of 25%, and those with poorly functioning implants had a weighted average of 60%. Again, positive patch testing to metals does not necessarily implicate allergy as the cause of implant failure.

Some small studies have shown that patients with evidence of metal hypersensitivity improve with revision. Zondervan et al¹¹ reviewed results of 46 orthopedic revisions following painful total knee arthroplasty. Patients with knee pain and lymphocyte transformation testing (LTT) positive for metals received hypoallergenic revisions, and those with LTT negative for metals received standard revisions. The group who received hypoallergenic revisions had more pain reduction compared to the standard revision group (37.8% reduction in pain vs 27%). However, this study was limited in that the diagnosis of metal allergy was made entirely on results of LTT.¹¹ In 2012, Atanaskova Mesinkovska et al¹² described 41 patients who underwent orthopedic patch testing following implantation for symptoms including pain, dermatitis, pruritus, joint loosening, edema, and impaired wound healing. Fifteen (37%) patients had positive patch test reactions to metals, and 10 (67%) of them had reactions to metals that were present in their implants. Six (60%) of these patients had their implants removed and their symptoms resolved; the remaining 4 continued to experience implant symptoms.¹² These studies support the existence of rare metal-related orthopedic IHRs and support the concept of proceeding with orthopedic implant revision when indicated, safe, and agreed upon by the surgeon and patient. However, as noted in the series by Zondervan et al,¹¹ not every patient with confirmed metal allergy who undergoes revision improves, so an informed conversation between the patient and surgeon is mandatory.

Types of Orthopedic Implants

Orthopedic implanted materials consist of either dynamic (knees, hips) or static (screws, plates) components. Several generations of hip implants have evolved since the 1960s. First-generation implanted hips were metal-on-metal and had high rates of metal release and sensitization. Metal-on-plastic implants may be less likely to release metal but instead release large polyethylene wear particles. Second-generation metal-on-metal implants reportedly have lower wear rates. With these implants, wear particles are generated but are reportedly smaller than first-generation particles.¹³

Allergens in IHRs

Metals
Metals are the most commonly implicated allergens in orthopedic IHRs. Potentially relevant metal alloys include 316L stainless steel, cobalt-chromium-molybdenum steel, Vitallium alloy, titanium alloy, titanium-tantalum-niobium alloy, and Oxinium (Smith & Nephew).^14,15 Each alloy contains several metals, which can include nickel, chromium, cobalt, manganese, molybdenum, iron, titanium, aluminum, vanadium, niobium, tantalum, and zirconium, among others. For example, 316L stainless steel contains iron, nickel, chromium, manganese, molybdenum, nitrogen, carbon, sulfur, silicon, and phosphorus, whereas Oxinium contains only oxidized zirconium and niobium.

Bone Cement
Bone cement also has been reported in cases of orthopedic IHRs and can contain several chemicals, including methyl methacrylate, N,N-dimethyl-p-toluidine, benzoyl peroxide, hydroquinone, and gentamicin.¹⁴ Other potential exposures include adhesives (cyanoacrylates) and topical antibiotics.

Clinical Presentation

Several clinical presentations of orthopedic IHRs have been described. Perhaps the most commonly recognized is a localized cutaneous eczematous eruption, with dermatitis typically overlying the site of the implanted material.^1,2,16 Generalized cutaneous eczematous IHRs also have been reported, including diffuse generalized dermatitis from a stainless steel orthopedic screw⁴ and nummular dermatitis attributed to vanadium in an orthopedic plate.⁵ Urticaria, vasculitis, and bullous cutaneous reactions, as well as extracutaneous complications, also have been reported.^14,15 Pain, edema, joint loosening or failure, and poor wound healing have been reported,¹² but it remains unclear whether these symptoms represent IHR.

Patch Testing for IHR

Several groups have published recommended patch test series for IHR.^12,14,15 Common components of implant patch testing panels include metals, adhesives (acrylates, epoxy resins) and antibiotics. Importantly, obtaining product information from the manufacturer of the suspected implant can guide which allergens to include in patch testing. Implant and metal panels also are available for commercial purchase.

Other Diagnostic Tests

We rarely (almost never) order LTTs in the workup for potential IHRs. This is an in vitro test that includes lymphocytes, metal ions, and the radioactive marker methyl-3H-thymidine. The goal of the test is to evaluate if patient lymphocytes are reactive or responsive to metal ions. A positive LTT suggests that lymphocytes can respond to the presence of metal ions but does not confirm allergy or the presence of IHR.

Typically, skin or tissue biopsies are not required to make a diagnosis of IHR; however, if performed, histopathology suggestive of IHR can support a suspected diagnosis. Typical findings include but are not limited to spongiotic dermatitis. Eosinophils may or may not be present. Metal disc testing has been utilized for orthopedic IHR but is not currently recommended due to low diagnostic yield. Prick testing rarely is used and also is not a primary method for diagnosis of IHR.¹⁷

Preimplantation Patch Testing

Expert opinion guidelines published by the American Contact Dermatitis Society (ACDS) state that routine preimplantation patch testing is not necessary; however, for those patients with a clear history of contact reactions to metal, preimplantation patch testing can be considered.¹⁷

Patch test results can influence the orthopedic surgeon’s choice of implant material. In one study, when preimplantation patch testing showed a positive patch test reaction to metals, the results influenced the surgeon’s decision-making in all cases.¹²

Postimplantation Patch Testing: Diagnostic Criteria for Metal IHR After Implantation

From 2012 to 2013, Schalock and Thyssen¹⁸ surveyed expert attendees at meetings of the European Society of Contact Dermatitis and the ACDS for their opinions on proposed diagnostic criteria for metal IHRs. Based on these results (N=119), the authors stratified 4 major and 5 minor diagnostic criteria, which were defined based on overall responses of meeting attendees. Major criteria included (1) chronic dermatitis beginning weeks to months after metallic implantation, (2) complete recovery after removal of the offending implant, (3) eruption overlying the metal implant, and (4) positive patch test reaction to a metal used in the implant. Minor criteria included (1) histology consistent with allergic contact dermatitis, (2) morphology consistent with dermatitis (ie, erythema, induration, papules, vesicles), (3) positive in vitro test to metals (eg, lymphocyte transformation test), (4) systemic allergic dermatitis reaction, and (5) therapy-resistant dermatitis reaction. The authors did not describe a scoring system for evaluation and confirmation of a diagnosis of IHR. Instead, the criteria should be used as general guidelines when evaluating patients for possible IHRs. From a standpoint of available diagnostic tests for metal IHR, 86.1% of experts agreed that a positive patch test reaction to a metal used in the implant was suggestive of a diagnosis, whereas a positive in vitro test to metals (LTT) was suggestive of a diagnosis for only 32.2% of respondents. This study was designed specifically for metal IHRs and therefore is not necessarily generalizable for nonmetal IHRs.¹⁸

Final Interpretation

We follow the 2016 ACDS guidelines¹⁷ and complete preimplantation patch testing only in the setting of suspected metal allergy and postimplantation patch testing based on the guidelines described by Schalock and Thyssen.¹⁸ However, an extended conversation is warranted prior to patch testing to ensure the patient fully understands the limitations of the test. Although we have both ordered the LTT, interpretation remains murky, and until this test is standardized, routine use is unlikely to benefit the patient. Until we are more reliably able to predict who will develop hypersensitivity to implanted metals, the decision to remove or revise an implant is one that should be made by a multidisciplinary team that includes the surgeon and the patient.

Recalcitrant acne is a common, unwavering problem in dermatology practices nationwide. However, both gram positive and gram negative infections of the skin can go undiagnosed in patients with acne resistant to the armamentarium of oral and topical therapeutics. Although I often use isotretinoin in patients with cystic or recalcitrant acne, I almost always do a culture prior to initiating therapy, and more often than not, have discovered patients have gram negative and gram positive skin infections resistant to antibiotics commonly used to treat acne.

Yulia Lisitsa/iStock/Getty Images Plus

Makeup is one of the most common culprits of recalcitrant acne. In a study by Bashir and Lambert published in the Journal of Applied Microbiology, 70%-90% of makeup products tested – including lipstick, lip gloss, beauty blenders, eyeliners, and mascara – were found to be contaminated with bacteria. Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were the most common culprits, and the product with the highest contamination rates were beauty blenders (the small sponges used to apply makeup), which also had high rates of fungal contamination.

Expiration dates on cosmetic products are used to indicate the length of time a preservative in a product can control bacterial contamination. They are printed on packaging as an open jar symbol with the 3M, 6M, 9M, and 12M label for the number of months the product can be opened and used. Unfortunately and unknowingly, most consumers use products beyond the expiration date, and the most common offender is mascara.

Gram positive and gram negative skin infections should be ruled out in all cases of recalcitrant acne. A reminder to note on all culture requisitions to grow gram negatives because not all labs will grow gram negatives on a skin swab. Counseling should also be given to those patients who wear makeup, which should include techniques to clean and sanitize makeup applicators including brushes, tools, and towels. Blenders are known to be used “wet” and are not dried when washed.

It is my recommendation that blenders be a one-time-use-only tool and disposed of after EVERY application. Instructions provided in my clinic are to wash all devices and brushes once a week with hot soapy water, and blow dry with a hair dryer immediately afterward. Lipsticks, mascara wands, and lip glosses should be sanitized with alcohol once a month. Finally, all products need to be disposed of after their expiry.

Dr. Talakoub and Dr. Wesley are cocontributors to this column. Dr. Talakoub is in private practice in McLean, Va. Dr. Wesley practices dermatology in Beverly Hills, Calif. This month’s column is by Dr. Talakoub. Write to them at [email protected]. They had no relevant disclosures.
 

Resource

Basher A, Lambert P. J Appl Microbiol. 2019. doi: 10.1111/jam.14479.

Recalcitrant acne is a common, unwavering problem in dermatology practices nationwide. However, both gram positive and gram negative infections of the skin can go undiagnosed in patients with acne resistant to the armamentarium of oral and topical therapeutics. Although I often use isotretinoin in patients with cystic or recalcitrant acne, I almost always do a culture prior to initiating therapy, and more often than not, have discovered patients have gram negative and gram positive skin infections resistant to antibiotics commonly used to treat acne.

Yulia Lisitsa/iStock/Getty Images Plus

Makeup is one of the most common culprits of recalcitrant acne. In a study by Bashir and Lambert published in the Journal of Applied Microbiology, 70%-90% of makeup products tested – including lipstick, lip gloss, beauty blenders, eyeliners, and mascara – were found to be contaminated with bacteria. Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were the most common culprits, and the product with the highest contamination rates were beauty blenders (the small sponges used to apply makeup), which also had high rates of fungal contamination.

Expiration dates on cosmetic products are used to indicate the length of time a preservative in a product can control bacterial contamination. They are printed on packaging as an open jar symbol with the 3M, 6M, 9M, and 12M label for the number of months the product can be opened and used. Unfortunately and unknowingly, most consumers use products beyond the expiration date, and the most common offender is mascara.

Gram positive and gram negative skin infections should be ruled out in all cases of recalcitrant acne. A reminder to note on all culture requisitions to grow gram negatives because not all labs will grow gram negatives on a skin swab. Counseling should also be given to those patients who wear makeup, which should include techniques to clean and sanitize makeup applicators including brushes, tools, and towels. Blenders are known to be used “wet” and are not dried when washed.

It is my recommendation that blenders be a one-time-use-only tool and disposed of after EVERY application. Instructions provided in my clinic are to wash all devices and brushes once a week with hot soapy water, and blow dry with a hair dryer immediately afterward. Lipsticks, mascara wands, and lip glosses should be sanitized with alcohol once a month. Finally, all products need to be disposed of after their expiry.

Dr. Talakoub and Dr. Wesley are cocontributors to this column. Dr. Talakoub is in private practice in McLean, Va. Dr. Wesley practices dermatology in Beverly Hills, Calif. This month’s column is by Dr. Talakoub. Write to them at [email protected]. They had no relevant disclosures.
 

Resource

Basher A, Lambert P. J Appl Microbiol. 2019. doi: 10.1111/jam.14479.

Recalcitrant acne is a common, unwavering problem in dermatology practices nationwide. However, both gram positive and gram negative infections of the skin can go undiagnosed in patients with acne resistant to the armamentarium of oral and topical therapeutics. Although I often use isotretinoin in patients with cystic or recalcitrant acne, I almost always do a culture prior to initiating therapy, and more often than not, have discovered patients have gram negative and gram positive skin infections resistant to antibiotics commonly used to treat acne.

Yulia Lisitsa/iStock/Getty Images Plus

Makeup is one of the most common culprits of recalcitrant acne. In a study by Bashir and Lambert published in the Journal of Applied Microbiology, 70%-90% of makeup products tested – including lipstick, lip gloss, beauty blenders, eyeliners, and mascara – were found to be contaminated with bacteria. Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli were the most common culprits, and the product with the highest contamination rates were beauty blenders (the small sponges used to apply makeup), which also had high rates of fungal contamination.

Expiration dates on cosmetic products are used to indicate the length of time a preservative in a product can control bacterial contamination. They are printed on packaging as an open jar symbol with the 3M, 6M, 9M, and 12M label for the number of months the product can be opened and used. Unfortunately and unknowingly, most consumers use products beyond the expiration date, and the most common offender is mascara.

Gram positive and gram negative skin infections should be ruled out in all cases of recalcitrant acne. A reminder to note on all culture requisitions to grow gram negatives because not all labs will grow gram negatives on a skin swab. Counseling should also be given to those patients who wear makeup, which should include techniques to clean and sanitize makeup applicators including brushes, tools, and towels. Blenders are known to be used “wet” and are not dried when washed.

It is my recommendation that blenders be a one-time-use-only tool and disposed of after EVERY application. Instructions provided in my clinic are to wash all devices and brushes once a week with hot soapy water, and blow dry with a hair dryer immediately afterward. Lipsticks, mascara wands, and lip glosses should be sanitized with alcohol once a month. Finally, all products need to be disposed of after their expiry.

Dr. Talakoub and Dr. Wesley are cocontributors to this column. Dr. Talakoub is in private practice in McLean, Va. Dr. Wesley practices dermatology in Beverly Hills, Calif. This month’s column is by Dr. Talakoub. Write to them at [email protected]. They had no relevant disclosures.
 

Resource

Basher A, Lambert P. J Appl Microbiol. 2019. doi: 10.1111/jam.14479.

Shiitake Mushroom Dermatitis 

Given the scattered and erythematous 1- to 2-mm macules and patches in a flagellate pattern on the shoulders, back, and neck, the differential diagnosis included shiitake mushroom dermatitis, bleomycin-induced flagellate dermatitis, dermatomyositis flagellate erythema, excoriation disorder, dermatographism, and keratosis lichenoides chronica. On further questioning, the patient indicated that he had consumed raw shiitake mushrooms 3 days before the onset of the rash. Although the clinical variability for all the conditions on the differential is notable, our patient had a history of consuming raw shiitake mushrooms, denied taking any medications, reported no repeated trauma, and had no muscular involvement or systemic symptoms, making shiitake mushroom dermatitis the most likely diagnosis.¹ Skin biopsy and blood tests were deemed unnecessary. Instead, the patient was prescribed triamcinolone cream 0.1%, counseled to avoid raw or undercooked shiitake mushrooms in the future, and told to follow-up if symptoms did not resolve. The patient's symptoms resolved, as expected. 

Nakamura² first described shiitake mushroom dermatitis in 1977. The condition also is known as flagellate mushroom dermatitis or shiitake toxicoderma. It classically manifests in susceptible patients as a pruritic, linear, flagellated dermatitis within 24 to 48 hours after the consumption of raw or undercooked shiitake mushrooms (Lentinula edodes).³ Although the complete pathogenesis remains unclear, research suggests that either a toxic reaction or a type IV hypersensitivity reaction to lentinan causes the eruption. Lentinan is a thermolabile polysaccharide within the mushroom that is believed to increase the production of IL-1 and cause vasodilatation.⁴  

Shiitake mushroom dermatitis is a clinical diagnosis based on the most common findings of a flagellate-pattern dermatitis consisting of pruritic and erythematous papular or urticarial lesions, usually found on the trunk. Laboratory tests, skin biopsies, and allergy tests have been shown to be nonspecific and inconsistent.⁵ 

Shiitake mushroom dermatitis is a self-limiting condition, with the majority of symptoms resolving after one to several weeks.⁵ The mainstay of treatment is aimed at symptomatic management and usually consists of topical corticosteroids and antihistamines.³ More rapid resolution of symptoms has been reported with the use of short-term balneo-psoralen plus UVA therapy.⁶ 

Although a 2017 review of the literature described only 9 published cases of shiitake mushroom dermatitis within the United States as of July 2015, this number may be misleading given the possibility of more variable and subtle presentations misdiagnosed as a nonspecific dermatitis.⁵ Given this information and the fact that shiitake mushrooms continue to be a popular choice in American cuisine, this case reminds health care providers of the clinical manifestations, differential diagnosis, and management of flagellate dermatitis caused by consuming shiitake mushrooms.

Shiitake Mushroom Dermatitis 

Given the scattered and erythematous 1- to 2-mm macules and patches in a flagellate pattern on the shoulders, back, and neck, the differential diagnosis included shiitake mushroom dermatitis, bleomycin-induced flagellate dermatitis, dermatomyositis flagellate erythema, excoriation disorder, dermatographism, and keratosis lichenoides chronica. On further questioning, the patient indicated that he had consumed raw shiitake mushrooms 3 days before the onset of the rash. Although the clinical variability for all the conditions on the differential is notable, our patient had a history of consuming raw shiitake mushrooms, denied taking any medications, reported no repeated trauma, and had no muscular involvement or systemic symptoms, making shiitake mushroom dermatitis the most likely diagnosis.¹ Skin biopsy and blood tests were deemed unnecessary. Instead, the patient was prescribed triamcinolone cream 0.1%, counseled to avoid raw or undercooked shiitake mushrooms in the future, and told to follow-up if symptoms did not resolve. The patient's symptoms resolved, as expected. 

Nakamura² first described shiitake mushroom dermatitis in 1977. The condition also is known as flagellate mushroom dermatitis or shiitake toxicoderma. It classically manifests in susceptible patients as a pruritic, linear, flagellated dermatitis within 24 to 48 hours after the consumption of raw or undercooked shiitake mushrooms (Lentinula edodes).³ Although the complete pathogenesis remains unclear, research suggests that either a toxic reaction or a type IV hypersensitivity reaction to lentinan causes the eruption. Lentinan is a thermolabile polysaccharide within the mushroom that is believed to increase the production of IL-1 and cause vasodilatation.⁴  

Shiitake mushroom dermatitis is a clinical diagnosis based on the most common findings of a flagellate-pattern dermatitis consisting of pruritic and erythematous papular or urticarial lesions, usually found on the trunk. Laboratory tests, skin biopsies, and allergy tests have been shown to be nonspecific and inconsistent.⁵ 

Shiitake mushroom dermatitis is a self-limiting condition, with the majority of symptoms resolving after one to several weeks.⁵ The mainstay of treatment is aimed at symptomatic management and usually consists of topical corticosteroids and antihistamines.³ More rapid resolution of symptoms has been reported with the use of short-term balneo-psoralen plus UVA therapy.⁶ 

Although a 2017 review of the literature described only 9 published cases of shiitake mushroom dermatitis within the United States as of July 2015, this number may be misleading given the possibility of more variable and subtle presentations misdiagnosed as a nonspecific dermatitis.⁵ Given this information and the fact that shiitake mushrooms continue to be a popular choice in American cuisine, this case reminds health care providers of the clinical manifestations, differential diagnosis, and management of flagellate dermatitis caused by consuming shiitake mushrooms.

Shiitake Mushroom Dermatitis 

Given the scattered and erythematous 1- to 2-mm macules and patches in a flagellate pattern on the shoulders, back, and neck, the differential diagnosis included shiitake mushroom dermatitis, bleomycin-induced flagellate dermatitis, dermatomyositis flagellate erythema, excoriation disorder, dermatographism, and keratosis lichenoides chronica. On further questioning, the patient indicated that he had consumed raw shiitake mushrooms 3 days before the onset of the rash. Although the clinical variability for all the conditions on the differential is notable, our patient had a history of consuming raw shiitake mushrooms, denied taking any medications, reported no repeated trauma, and had no muscular involvement or systemic symptoms, making shiitake mushroom dermatitis the most likely diagnosis.¹ Skin biopsy and blood tests were deemed unnecessary. Instead, the patient was prescribed triamcinolone cream 0.1%, counseled to avoid raw or undercooked shiitake mushrooms in the future, and told to follow-up if symptoms did not resolve. The patient's symptoms resolved, as expected. 

Nakamura² first described shiitake mushroom dermatitis in 1977. The condition also is known as flagellate mushroom dermatitis or shiitake toxicoderma. It classically manifests in susceptible patients as a pruritic, linear, flagellated dermatitis within 24 to 48 hours after the consumption of raw or undercooked shiitake mushrooms (Lentinula edodes).³ Although the complete pathogenesis remains unclear, research suggests that either a toxic reaction or a type IV hypersensitivity reaction to lentinan causes the eruption. Lentinan is a thermolabile polysaccharide within the mushroom that is believed to increase the production of IL-1 and cause vasodilatation.⁴  

Shiitake mushroom dermatitis is a clinical diagnosis based on the most common findings of a flagellate-pattern dermatitis consisting of pruritic and erythematous papular or urticarial lesions, usually found on the trunk. Laboratory tests, skin biopsies, and allergy tests have been shown to be nonspecific and inconsistent.⁵ 

Shiitake mushroom dermatitis is a self-limiting condition, with the majority of symptoms resolving after one to several weeks.⁵ The mainstay of treatment is aimed at symptomatic management and usually consists of topical corticosteroids and antihistamines.³ More rapid resolution of symptoms has been reported with the use of short-term balneo-psoralen plus UVA therapy.⁶ 

Although a 2017 review of the literature described only 9 published cases of shiitake mushroom dermatitis within the United States as of July 2015, this number may be misleading given the possibility of more variable and subtle presentations misdiagnosed as a nonspecific dermatitis.⁵ Given this information and the fact that shiitake mushrooms continue to be a popular choice in American cuisine, this case reminds health care providers of the clinical manifestations, differential diagnosis, and management of flagellate dermatitis caused by consuming shiitake mushrooms.

One of the perils of patch testing is fielding questions about which type of allergens will be used. Patients often ask if the patch test includes milk, foods, dander, mold, pets, and grass. Most patch testers spend a substantial amount of time explaining that the purpose of patch testing is to detect applied chemical allergens: It’s not what you eat; rather, it’s what touches your skin. However, the big caveat is that some oral, parenteral, inhaled, and even cutaneous allergens can produce systemic contact dermatitis (SCD), which represents a unique clinical scenario that we will review in this month’s Final Interpretation column.

There are many patterns of SCD. Familiarity with potential clinical presentations can aid in diagnosis and counseling. Systemic contact dermatitis tends to be symmetrical. Dyshidrotic hand dermatitis is a reported pattern for systemic metal allergy, most commonly nickel. Refractory eyelid or genital dermatitis can reflect a systemic exposure, particularly if the dermatitis is in areas not caused by direct skin contact with the allergen. Systemic drug-related intertriginous and flexural exanthema is, as the name describes, an eruption involving axillae, genital skin, and flexural sites. It usually is a type of drug reaction, but the culprit can be an ingested allergen. So-called baboon syndrome SCD can cause persistent genital and intertriginous dermatitis. Other clues to SCD include dermatitis flare at the patch test site and erythema multiforme. Some patients also describe systemic symptoms, including headache, fatigue, and malaise.

Rhus Dermatitis

Poison ivy is the most common cause of acute contact dermatitis but also can be a cause of SCD. From the family Anacardiaceae, this sneaky plant is common in many parts of the United States; most allergic patients are familiar with their allergy from prior exposure.

In 1982, 54 Little League baseball attendees developed diffuse vesicular dermatitis involving the flexures after ingesting packaged cashews contaminated with cashew shells.¹ In the same family as poison ivy, the cashew nut tree (Anacardium occidentale) produces a cashew apple containing the cashew nut. The cashew shell is the site that contains the allergenic oils. Typically, cashews are processed to remove the shell and oil prior to consumption. Ingestion of raw cashews is more likely to lead to SCD than roasted cashews because the heat in the roasting process can break down any allergenic oil.²

Metals

Systemic exposures to nickel usually are dietary. Clinically, SCD from nickel most commonly presents as refractory dyshidrotic hand eczema or papular elbow dermatitis.³ Nickel is commonly found in vitamins and supplements as well as certain whole grains, vegetables, beans, coffee, chocolate, and tea.⁴ Sometimes, cookware also can be a source of nickel exposure, particularly with steel cookware, from which nickel can leach into food.

In general, a diet lower than 150 μg/d is needed to prevent flares.⁵ A point-based diet is available for nickel-allergic patients.⁵ Patients should ingest a restricted amount of nickel (15 points daily); those who are extremely allergic might need to limit nickel ingestion to less than 5 points daily. Because of the challenges associated with maintaining a low-nickel diet, chelation therapy has been recommended to prevent nickel absorption. Disulfiram³ and ascorbic acid⁵ have been recommended, but larger studies are lacking.

Cobalt and chromium are other metals that, when ingested, can lead to SCD; both can be found in multivitamins. Other sources of dietary chromium include vegetables, coffee, beans, certain meats, and seafood.⁴ For cobalt, the dietary exposures are similar with the addition of nuts, apricots, and whole-grain flour. A point-based cobalt avoidance diet has been published. This diet recommends less than 12 μg of cobalt daily; patients can ingest up to 12 cobalt points daily.⁶

Likewise, gold has been reported to cause SCD, with one case attributed to gold in a homeopathic cardiac medication.⁷ Gold SCD also should be considered in the setting of ingested gold-containing alcoholic beverages and historically has been associated with intramuscular gold sodium thiomalate for the treatment of rheumatoid arthritis.⁸

Metal implants, including prosthetic joints, stents, and other devices, have been implicated in SCD. (More to come on this topic soon; yes, dear reader, that is a teaser!)

Fragrances

Balsam of Peru
Secreted by the tree Myroxylon balsamum var pereirae, balsam of Peru (BOP) contains several potential allergens, including cinnamon oils (eg, eugenol, vanillin, cinnamates), coniferin derivatives, and benzoic acid derivatives.⁹ Foods and beverages associated with BOP include citrus, pickled vegetables, chocolate, ice cream, chili, pizza, tomatoes, wine, beer, gin, vermouth, flavored tea, and soft drinks.¹⁰ Flavoring agents, spices (eg, cloves, curry, vanilla, cinnamon, allspice, ginger, anise), and condiments (eg, ketchup, barbeque sauce) are potential sources, as are cough medicines, lozenges, and flavored tobacco.

Salam and Fowler¹⁰ described BOP-allergic patients whose condition improved with dietary restriction of BOP. Avoidance of tomatoes, citrus, spices, and cola most commonly contributed to improvement.¹⁰ Scheman et al⁹ proposed BOP subgroups, including the eugenol, vanillin, cinnamate, benzoate, ferulic acid, and coniferin groups. Targeted patch testing can identify relevant subgroups, and patients can focus dietary restrictions by subgroup.

Plants
Systemic contact dermatitis has been reported in association with a number of plants and herbals, including chamomile in tea,¹¹ goldenrod in a medicated extract,¹²Hosta plantaginea roots,¹³ and garlic extract for hyperlipidemia.¹⁴ Many more have been described.

Propolis
Also known as bee glue, propolis comprises a mixture of balsams, resins, waxes, essential oils, pollen, cinnamic alcohol, and vitamins. It can be found in many cosmetic products, foods, and chewing gum.¹⁵ Propolis has been reported to be the source of SCD from ingestion of propolis capsules, which have been used to promote immune stimulation,¹⁵ and propolis solution as a natural tonic.¹⁶

Propylene Glycol

Propylene glycol (PG) can be found in (believe it or not) foods and medications. In foods, it typically is used for its softening, humectant, and preservative properties.¹⁷ Common food sources of PG include sauces, desserts, snack foods, and salad dressings.

Many topical prescription medications, including corticosteroids and newer nonsteroidal anti-inflammatory topicals, might contain PG; providers must specifically request PG-free products for PG-allergic patients. A detailed PG-avoidance diet lists products to avoid and products that are PG free.¹⁸

Preservatives

Sulfites
These compounds are preservatives found in cosmetics, hair dyes, and certain foods. Systemic contact dermatitis caused by sulfites in food has been described in numerous patients. One unfortunate vacationer developed axillary and groin dermatitis after ingesting large amounts of grapes, wine, shrimp, and french fries while vacationing in Italy.¹⁹ Among dietary sources, beer and wine contain higher levels of sulfites. Sulfites also can be found in some pickled foods; bottled citrus juice; dried fruits; and commercial prepared foods, such as powdered potatoes and gravy mixes. Other reports of SCD from sulfites include an enema preparation²⁰ and anesthetics²¹ as the source of the allergen.

Formaldehyde
Formaldehyde can cause SCD after ingestion of aspartame, which is hydrolyzed to phenylalanine, aspartic acid, and aspartic acid methyl ester in the intestine.²² The methyl ester is converted to methyl alcohol, which is transported to the liver and oxidized to formaldehyde, which is then converted to formic acid. Hill and Belsito²² reported a case of SCD presenting as eyelid dermatitis after ingestion of an aspartame-based artificial sweetener. A similar case of eyelid, neck, and leg dermatitis was reported after ingestion of drinks and candy sweetened with aspartame.²³

Parabens
Although parabens are rare contact sensitizers, there are a few reports of paraben SCD. Cases include a predominantly flexural pattern from ingestion of a mucolytic-containing methylparaben,²⁴ a generalized eczematous eruption after intramuscular injection of ampicillin preserved with methylparaben and propylparaben,²⁵ and diffuse dermatitis from methylparaben in a local anesthetic.²⁶

Sorbic Acid
Sorbic acid is utilized as a preservative in foods and occurs naturally in red fruit, such as strawberries and cranberries.²⁷ It is a rare allergen, but several cases of sorbic acid SCD have been reported, including perianal and buttock dermatitis,²⁷ hand dermatitis in an infant,²⁸ and hand-and-foot dermatitis in a storekeeper.²⁹

Carmine

Carmine, or cochineal extract, is a red dye derived from dried pulverized scale insects of the family Coccidae. This chemical can be used in a multitude of foods and medications, including candies, yogurt, red velvet items, popsicles, food coloring, frozen meat and fish, ice cream, syrups, ketchup, sausage, donuts, cake pops, applesauce, canned fruits, soups, and drinks.³⁰ Machler and Jacob³¹ described a child with recurrent episodes of erythroderma and periorbital edema in whom patch testing revealed a reaction to carmine. The patient’s mother connected the flares with ingestion of red velvet cupcakes.³¹ Ferris et al³² reported a likely case of SCD attributed to carmine in a multivitamin.

Steroids

Ingested and injected corticosteroids have been associated with SCD, which is illustrated by a case of a generalized cutaneous eruption several days after joint injection with triamcinolone acetonide.³³ In another report, a patient developed an eruption in the body folds, later generalized, after topical application of a corticosteroid, first in ear drops and later in nasal spray.³⁴ Traditional corticosteroid classification systems might be less reliable in predicting relevant allergens in corticosteroid SCD; comprehensive testing, including oral challenge, might be necessary to identify alternatives.³³

Ethylenediamine

Ethylenediamine is an uncommon allergen in patch test populations. It is present in aminophylline³⁵ and is utilized in the production of hydroxyzine³⁶ and other piperazine-derived medications, such as cetirizine, levocetirizine, meclizine, and olanzapine. Several cases of SCD caused by aminophylline,³⁵ cetirizine,³⁶ and hydroxyzine³⁷ have been reported, all in the setting of a positive patch test reaction to ethylenediamine.

When to Counsel About Systemic Exposures

In general, we usually do not counsel on systemic exposures to allergens at the final patch test reading unless the pattern of dermatitis or clinical history strongly suggests systemic exposure. In most cases, we find that counseling on topical allergen avoidance alone is sufficient to treat allergic contact dermatitis. Because of the restrictive nature of allergen-avoidance diets, counseling all patients on the potential for SCD might cause undue stress without much benefit. However, if a patient experiences persistent dermatitis on follow-up with topical avoidance alone, we often will delve into systemic exposures and counsel on further avoidance strategies, including medication and diet.

Final Interpretation

A multitude of chemicals have been reported as the source of SCD; these exposures can occur through ingestion, injection, and inhaled and cutaneous routes. Chemicals present in foods, medications, and beverages have been implicated. Systemic contact dermatitis is rare and should be considered when traditional avoidance of contact allergens is unsuccessful and the clinical pattern is consistent with SCD.

One of the perils of patch testing is fielding questions about which type of allergens will be used. Patients often ask if the patch test includes milk, foods, dander, mold, pets, and grass. Most patch testers spend a substantial amount of time explaining that the purpose of patch testing is to detect applied chemical allergens: It’s not what you eat; rather, it’s what touches your skin. However, the big caveat is that some oral, parenteral, inhaled, and even cutaneous allergens can produce systemic contact dermatitis (SCD), which represents a unique clinical scenario that we will review in this month’s Final Interpretation column.

There are many patterns of SCD. Familiarity with potential clinical presentations can aid in diagnosis and counseling. Systemic contact dermatitis tends to be symmetrical. Dyshidrotic hand dermatitis is a reported pattern for systemic metal allergy, most commonly nickel. Refractory eyelid or genital dermatitis can reflect a systemic exposure, particularly if the dermatitis is in areas not caused by direct skin contact with the allergen. Systemic drug-related intertriginous and flexural exanthema is, as the name describes, an eruption involving axillae, genital skin, and flexural sites. It usually is a type of drug reaction, but the culprit can be an ingested allergen. So-called baboon syndrome SCD can cause persistent genital and intertriginous dermatitis. Other clues to SCD include dermatitis flare at the patch test site and erythema multiforme. Some patients also describe systemic symptoms, including headache, fatigue, and malaise.

Rhus Dermatitis

Poison ivy is the most common cause of acute contact dermatitis but also can be a cause of SCD. From the family Anacardiaceae, this sneaky plant is common in many parts of the United States; most allergic patients are familiar with their allergy from prior exposure.

In 1982, 54 Little League baseball attendees developed diffuse vesicular dermatitis involving the flexures after ingesting packaged cashews contaminated with cashew shells.¹ In the same family as poison ivy, the cashew nut tree (Anacardium occidentale) produces a cashew apple containing the cashew nut. The cashew shell is the site that contains the allergenic oils. Typically, cashews are processed to remove the shell and oil prior to consumption. Ingestion of raw cashews is more likely to lead to SCD than roasted cashews because the heat in the roasting process can break down any allergenic oil.²

Metals

Systemic exposures to nickel usually are dietary. Clinically, SCD from nickel most commonly presents as refractory dyshidrotic hand eczema or papular elbow dermatitis.³ Nickel is commonly found in vitamins and supplements as well as certain whole grains, vegetables, beans, coffee, chocolate, and tea.⁴ Sometimes, cookware also can be a source of nickel exposure, particularly with steel cookware, from which nickel can leach into food.

In general, a diet lower than 150 μg/d is needed to prevent flares.⁵ A point-based diet is available for nickel-allergic patients.⁵ Patients should ingest a restricted amount of nickel (15 points daily); those who are extremely allergic might need to limit nickel ingestion to less than 5 points daily. Because of the challenges associated with maintaining a low-nickel diet, chelation therapy has been recommended to prevent nickel absorption. Disulfiram³ and ascorbic acid⁵ have been recommended, but larger studies are lacking.

Cobalt and chromium are other metals that, when ingested, can lead to SCD; both can be found in multivitamins. Other sources of dietary chromium include vegetables, coffee, beans, certain meats, and seafood.⁴ For cobalt, the dietary exposures are similar with the addition of nuts, apricots, and whole-grain flour. A point-based cobalt avoidance diet has been published. This diet recommends less than 12 μg of cobalt daily; patients can ingest up to 12 cobalt points daily.⁶

Likewise, gold has been reported to cause SCD, with one case attributed to gold in a homeopathic cardiac medication.⁷ Gold SCD also should be considered in the setting of ingested gold-containing alcoholic beverages and historically has been associated with intramuscular gold sodium thiomalate for the treatment of rheumatoid arthritis.⁸

Metal implants, including prosthetic joints, stents, and other devices, have been implicated in SCD. (More to come on this topic soon; yes, dear reader, that is a teaser!)

Fragrances

Balsam of Peru
Secreted by the tree Myroxylon balsamum var pereirae, balsam of Peru (BOP) contains several potential allergens, including cinnamon oils (eg, eugenol, vanillin, cinnamates), coniferin derivatives, and benzoic acid derivatives.⁹ Foods and beverages associated with BOP include citrus, pickled vegetables, chocolate, ice cream, chili, pizza, tomatoes, wine, beer, gin, vermouth, flavored tea, and soft drinks.¹⁰ Flavoring agents, spices (eg, cloves, curry, vanilla, cinnamon, allspice, ginger, anise), and condiments (eg, ketchup, barbeque sauce) are potential sources, as are cough medicines, lozenges, and flavored tobacco.

Salam and Fowler¹⁰ described BOP-allergic patients whose condition improved with dietary restriction of BOP. Avoidance of tomatoes, citrus, spices, and cola most commonly contributed to improvement.¹⁰ Scheman et al⁹ proposed BOP subgroups, including the eugenol, vanillin, cinnamate, benzoate, ferulic acid, and coniferin groups. Targeted patch testing can identify relevant subgroups, and patients can focus dietary restrictions by subgroup.

Plants
Systemic contact dermatitis has been reported in association with a number of plants and herbals, including chamomile in tea,¹¹ goldenrod in a medicated extract,¹²Hosta plantaginea roots,¹³ and garlic extract for hyperlipidemia.¹⁴ Many more have been described.

Propolis
Also known as bee glue, propolis comprises a mixture of balsams, resins, waxes, essential oils, pollen, cinnamic alcohol, and vitamins. It can be found in many cosmetic products, foods, and chewing gum.¹⁵ Propolis has been reported to be the source of SCD from ingestion of propolis capsules, which have been used to promote immune stimulation,¹⁵ and propolis solution as a natural tonic.¹⁶

Propylene Glycol

Propylene glycol (PG) can be found in (believe it or not) foods and medications. In foods, it typically is used for its softening, humectant, and preservative properties.¹⁷ Common food sources of PG include sauces, desserts, snack foods, and salad dressings.

Many topical prescription medications, including corticosteroids and newer nonsteroidal anti-inflammatory topicals, might contain PG; providers must specifically request PG-free products for PG-allergic patients. A detailed PG-avoidance diet lists products to avoid and products that are PG free.¹⁸

Preservatives

Sulfites
These compounds are preservatives found in cosmetics, hair dyes, and certain foods. Systemic contact dermatitis caused by sulfites in food has been described in numerous patients. One unfortunate vacationer developed axillary and groin dermatitis after ingesting large amounts of grapes, wine, shrimp, and french fries while vacationing in Italy.¹⁹ Among dietary sources, beer and wine contain higher levels of sulfites. Sulfites also can be found in some pickled foods; bottled citrus juice; dried fruits; and commercial prepared foods, such as powdered potatoes and gravy mixes. Other reports of SCD from sulfites include an enema preparation²⁰ and anesthetics²¹ as the source of the allergen.

Formaldehyde
Formaldehyde can cause SCD after ingestion of aspartame, which is hydrolyzed to phenylalanine, aspartic acid, and aspartic acid methyl ester in the intestine.²² The methyl ester is converted to methyl alcohol, which is transported to the liver and oxidized to formaldehyde, which is then converted to formic acid. Hill and Belsito²² reported a case of SCD presenting as eyelid dermatitis after ingestion of an aspartame-based artificial sweetener. A similar case of eyelid, neck, and leg dermatitis was reported after ingestion of drinks and candy sweetened with aspartame.²³

Parabens
Although parabens are rare contact sensitizers, there are a few reports of paraben SCD. Cases include a predominantly flexural pattern from ingestion of a mucolytic-containing methylparaben,²⁴ a generalized eczematous eruption after intramuscular injection of ampicillin preserved with methylparaben and propylparaben,²⁵ and diffuse dermatitis from methylparaben in a local anesthetic.²⁶

Sorbic Acid
Sorbic acid is utilized as a preservative in foods and occurs naturally in red fruit, such as strawberries and cranberries.²⁷ It is a rare allergen, but several cases of sorbic acid SCD have been reported, including perianal and buttock dermatitis,²⁷ hand dermatitis in an infant,²⁸ and hand-and-foot dermatitis in a storekeeper.²⁹

Carmine

Carmine, or cochineal extract, is a red dye derived from dried pulverized scale insects of the family Coccidae. This chemical can be used in a multitude of foods and medications, including candies, yogurt, red velvet items, popsicles, food coloring, frozen meat and fish, ice cream, syrups, ketchup, sausage, donuts, cake pops, applesauce, canned fruits, soups, and drinks.³⁰ Machler and Jacob³¹ described a child with recurrent episodes of erythroderma and periorbital edema in whom patch testing revealed a reaction to carmine. The patient’s mother connected the flares with ingestion of red velvet cupcakes.³¹ Ferris et al³² reported a likely case of SCD attributed to carmine in a multivitamin.

Steroids

Ingested and injected corticosteroids have been associated with SCD, which is illustrated by a case of a generalized cutaneous eruption several days after joint injection with triamcinolone acetonide.³³ In another report, a patient developed an eruption in the body folds, later generalized, after topical application of a corticosteroid, first in ear drops and later in nasal spray.³⁴ Traditional corticosteroid classification systems might be less reliable in predicting relevant allergens in corticosteroid SCD; comprehensive testing, including oral challenge, might be necessary to identify alternatives.³³

Ethylenediamine

Ethylenediamine is an uncommon allergen in patch test populations. It is present in aminophylline³⁵ and is utilized in the production of hydroxyzine³⁶ and other piperazine-derived medications, such as cetirizine, levocetirizine, meclizine, and olanzapine. Several cases of SCD caused by aminophylline,³⁵ cetirizine,³⁶ and hydroxyzine³⁷ have been reported, all in the setting of a positive patch test reaction to ethylenediamine.

When to Counsel About Systemic Exposures

In general, we usually do not counsel on systemic exposures to allergens at the final patch test reading unless the pattern of dermatitis or clinical history strongly suggests systemic exposure. In most cases, we find that counseling on topical allergen avoidance alone is sufficient to treat allergic contact dermatitis. Because of the restrictive nature of allergen-avoidance diets, counseling all patients on the potential for SCD might cause undue stress without much benefit. However, if a patient experiences persistent dermatitis on follow-up with topical avoidance alone, we often will delve into systemic exposures and counsel on further avoidance strategies, including medication and diet.

Final Interpretation

A multitude of chemicals have been reported as the source of SCD; these exposures can occur through ingestion, injection, and inhaled and cutaneous routes. Chemicals present in foods, medications, and beverages have been implicated. Systemic contact dermatitis is rare and should be considered when traditional avoidance of contact allergens is unsuccessful and the clinical pattern is consistent with SCD.

One of the perils of patch testing is fielding questions about which type of allergens will be used. Patients often ask if the patch test includes milk, foods, dander, mold, pets, and grass. Most patch testers spend a substantial amount of time explaining that the purpose of patch testing is to detect applied chemical allergens: It’s not what you eat; rather, it’s what touches your skin. However, the big caveat is that some oral, parenteral, inhaled, and even cutaneous allergens can produce systemic contact dermatitis (SCD), which represents a unique clinical scenario that we will review in this month’s Final Interpretation column.

There are many patterns of SCD. Familiarity with potential clinical presentations can aid in diagnosis and counseling. Systemic contact dermatitis tends to be symmetrical. Dyshidrotic hand dermatitis is a reported pattern for systemic metal allergy, most commonly nickel. Refractory eyelid or genital dermatitis can reflect a systemic exposure, particularly if the dermatitis is in areas not caused by direct skin contact with the allergen. Systemic drug-related intertriginous and flexural exanthema is, as the name describes, an eruption involving axillae, genital skin, and flexural sites. It usually is a type of drug reaction, but the culprit can be an ingested allergen. So-called baboon syndrome SCD can cause persistent genital and intertriginous dermatitis. Other clues to SCD include dermatitis flare at the patch test site and erythema multiforme. Some patients also describe systemic symptoms, including headache, fatigue, and malaise.

Rhus Dermatitis

Poison ivy is the most common cause of acute contact dermatitis but also can be a cause of SCD. From the family Anacardiaceae, this sneaky plant is common in many parts of the United States; most allergic patients are familiar with their allergy from prior exposure.

In 1982, 54 Little League baseball attendees developed diffuse vesicular dermatitis involving the flexures after ingesting packaged cashews contaminated with cashew shells.¹ In the same family as poison ivy, the cashew nut tree (Anacardium occidentale) produces a cashew apple containing the cashew nut. The cashew shell is the site that contains the allergenic oils. Typically, cashews are processed to remove the shell and oil prior to consumption. Ingestion of raw cashews is more likely to lead to SCD than roasted cashews because the heat in the roasting process can break down any allergenic oil.²

Metals

Systemic exposures to nickel usually are dietary. Clinically, SCD from nickel most commonly presents as refractory dyshidrotic hand eczema or papular elbow dermatitis.³ Nickel is commonly found in vitamins and supplements as well as certain whole grains, vegetables, beans, coffee, chocolate, and tea.⁴ Sometimes, cookware also can be a source of nickel exposure, particularly with steel cookware, from which nickel can leach into food.

In general, a diet lower than 150 μg/d is needed to prevent flares.⁵ A point-based diet is available for nickel-allergic patients.⁵ Patients should ingest a restricted amount of nickel (15 points daily); those who are extremely allergic might need to limit nickel ingestion to less than 5 points daily. Because of the challenges associated with maintaining a low-nickel diet, chelation therapy has been recommended to prevent nickel absorption. Disulfiram³ and ascorbic acid⁵ have been recommended, but larger studies are lacking.

Cobalt and chromium are other metals that, when ingested, can lead to SCD; both can be found in multivitamins. Other sources of dietary chromium include vegetables, coffee, beans, certain meats, and seafood.⁴ For cobalt, the dietary exposures are similar with the addition of nuts, apricots, and whole-grain flour. A point-based cobalt avoidance diet has been published. This diet recommends less than 12 μg of cobalt daily; patients can ingest up to 12 cobalt points daily.⁶

Likewise, gold has been reported to cause SCD, with one case attributed to gold in a homeopathic cardiac medication.⁷ Gold SCD also should be considered in the setting of ingested gold-containing alcoholic beverages and historically has been associated with intramuscular gold sodium thiomalate for the treatment of rheumatoid arthritis.⁸

Metal implants, including prosthetic joints, stents, and other devices, have been implicated in SCD. (More to come on this topic soon; yes, dear reader, that is a teaser!)

Fragrances

Balsam of Peru
Secreted by the tree Myroxylon balsamum var pereirae, balsam of Peru (BOP) contains several potential allergens, including cinnamon oils (eg, eugenol, vanillin, cinnamates), coniferin derivatives, and benzoic acid derivatives.⁹ Foods and beverages associated with BOP include citrus, pickled vegetables, chocolate, ice cream, chili, pizza, tomatoes, wine, beer, gin, vermouth, flavored tea, and soft drinks.¹⁰ Flavoring agents, spices (eg, cloves, curry, vanilla, cinnamon, allspice, ginger, anise), and condiments (eg, ketchup, barbeque sauce) are potential sources, as are cough medicines, lozenges, and flavored tobacco.

Salam and Fowler¹⁰ described BOP-allergic patients whose condition improved with dietary restriction of BOP. Avoidance of tomatoes, citrus, spices, and cola most commonly contributed to improvement.¹⁰ Scheman et al⁹ proposed BOP subgroups, including the eugenol, vanillin, cinnamate, benzoate, ferulic acid, and coniferin groups. Targeted patch testing can identify relevant subgroups, and patients can focus dietary restrictions by subgroup.

Plants
Systemic contact dermatitis has been reported in association with a number of plants and herbals, including chamomile in tea,¹¹ goldenrod in a medicated extract,¹²Hosta plantaginea roots,¹³ and garlic extract for hyperlipidemia.¹⁴ Many more have been described.

Propolis
Also known as bee glue, propolis comprises a mixture of balsams, resins, waxes, essential oils, pollen, cinnamic alcohol, and vitamins. It can be found in many cosmetic products, foods, and chewing gum.¹⁵ Propolis has been reported to be the source of SCD from ingestion of propolis capsules, which have been used to promote immune stimulation,¹⁵ and propolis solution as a natural tonic.¹⁶

Propylene Glycol

Propylene glycol (PG) can be found in (believe it or not) foods and medications. In foods, it typically is used for its softening, humectant, and preservative properties.¹⁷ Common food sources of PG include sauces, desserts, snack foods, and salad dressings.

Many topical prescription medications, including corticosteroids and newer nonsteroidal anti-inflammatory topicals, might contain PG; providers must specifically request PG-free products for PG-allergic patients. A detailed PG-avoidance diet lists products to avoid and products that are PG free.¹⁸

Preservatives

Sulfites
These compounds are preservatives found in cosmetics, hair dyes, and certain foods. Systemic contact dermatitis caused by sulfites in food has been described in numerous patients. One unfortunate vacationer developed axillary and groin dermatitis after ingesting large amounts of grapes, wine, shrimp, and french fries while vacationing in Italy.¹⁹ Among dietary sources, beer and wine contain higher levels of sulfites. Sulfites also can be found in some pickled foods; bottled citrus juice; dried fruits; and commercial prepared foods, such as powdered potatoes and gravy mixes. Other reports of SCD from sulfites include an enema preparation²⁰ and anesthetics²¹ as the source of the allergen.

Formaldehyde
Formaldehyde can cause SCD after ingestion of aspartame, which is hydrolyzed to phenylalanine, aspartic acid, and aspartic acid methyl ester in the intestine.²² The methyl ester is converted to methyl alcohol, which is transported to the liver and oxidized to formaldehyde, which is then converted to formic acid. Hill and Belsito²² reported a case of SCD presenting as eyelid dermatitis after ingestion of an aspartame-based artificial sweetener. A similar case of eyelid, neck, and leg dermatitis was reported after ingestion of drinks and candy sweetened with aspartame.²³

Parabens
Although parabens are rare contact sensitizers, there are a few reports of paraben SCD. Cases include a predominantly flexural pattern from ingestion of a mucolytic-containing methylparaben,²⁴ a generalized eczematous eruption after intramuscular injection of ampicillin preserved with methylparaben and propylparaben,²⁵ and diffuse dermatitis from methylparaben in a local anesthetic.²⁶

Sorbic Acid
Sorbic acid is utilized as a preservative in foods and occurs naturally in red fruit, such as strawberries and cranberries.²⁷ It is a rare allergen, but several cases of sorbic acid SCD have been reported, including perianal and buttock dermatitis,²⁷ hand dermatitis in an infant,²⁸ and hand-and-foot dermatitis in a storekeeper.²⁹

Carmine

Carmine, or cochineal extract, is a red dye derived from dried pulverized scale insects of the family Coccidae. This chemical can be used in a multitude of foods and medications, including candies, yogurt, red velvet items, popsicles, food coloring, frozen meat and fish, ice cream, syrups, ketchup, sausage, donuts, cake pops, applesauce, canned fruits, soups, and drinks.³⁰ Machler and Jacob³¹ described a child with recurrent episodes of erythroderma and periorbital edema in whom patch testing revealed a reaction to carmine. The patient’s mother connected the flares with ingestion of red velvet cupcakes.³¹ Ferris et al³² reported a likely case of SCD attributed to carmine in a multivitamin.

Steroids

Ingested and injected corticosteroids have been associated with SCD, which is illustrated by a case of a generalized cutaneous eruption several days after joint injection with triamcinolone acetonide.³³ In another report, a patient developed an eruption in the body folds, later generalized, after topical application of a corticosteroid, first in ear drops and later in nasal spray.³⁴ Traditional corticosteroid classification systems might be less reliable in predicting relevant allergens in corticosteroid SCD; comprehensive testing, including oral challenge, might be necessary to identify alternatives.³³

Ethylenediamine

Ethylenediamine is an uncommon allergen in patch test populations. It is present in aminophylline³⁵ and is utilized in the production of hydroxyzine³⁶ and other piperazine-derived medications, such as cetirizine, levocetirizine, meclizine, and olanzapine. Several cases of SCD caused by aminophylline,³⁵ cetirizine,³⁶ and hydroxyzine³⁷ have been reported, all in the setting of a positive patch test reaction to ethylenediamine.

When to Counsel About Systemic Exposures

In general, we usually do not counsel on systemic exposures to allergens at the final patch test reading unless the pattern of dermatitis or clinical history strongly suggests systemic exposure. In most cases, we find that counseling on topical allergen avoidance alone is sufficient to treat allergic contact dermatitis. Because of the restrictive nature of allergen-avoidance diets, counseling all patients on the potential for SCD might cause undue stress without much benefit. However, if a patient experiences persistent dermatitis on follow-up with topical avoidance alone, we often will delve into systemic exposures and counsel on further avoidance strategies, including medication and diet.

Final Interpretation

A multitude of chemicals have been reported as the source of SCD; these exposures can occur through ingestion, injection, and inhaled and cutaneous routes. Chemicals present in foods, medications, and beverages have been implicated. Systemic contact dermatitis is rare and should be considered when traditional avoidance of contact allergens is unsuccessful and the clinical pattern is consistent with SCD.

The pediatric population has a unique product exposure profile due to the many care products specifically marketed for use in children. In fact, the prevalence of allergic contact dermatitis (ACD) in children may be as high as 24.5% in the United States.¹ In patch tested children, relevant positive reaction rates of 56.7% and 48% have been reported by the North American Contact Dermatitis Group and the Pediatric Contact Dermatitis Registry, respectively.^2,3 In this article, we provide an overview of current trends in pediatric patch testing as well as specific considerations in this patient population.

Patch Test Reactions in Children

Several publications have documented pediatric patch test reactions. The North American Contact Dermatitis Group reported patch test results in 883 children from the United States and Canada (2005-2012).² The most common reactions were nickel (28.1%), cobalt (12.3%), neomycin (7.1%), balsam of Peru (5.7%), lanolin (5.5%), and fragrance mix I (5.2%). When compared to adults, children were more likely to have relevant positive patch tests to nickel, cobalt, and compositae mix.² In comparison, data from the Pediatric Contact Dermatitis Registry showed that the most common reactions in 1142 children in the United States (2015-2016) were nickel (22%), fragrance mix I (11%), cobalt (9.1%), balsam of Peru (8.4%), neomycin (7.2%), and propylene glycol (6.8%).³

Allergen sensitivities may vary based on geographic region. In Spain, children showed the highest sensitivities to thiomersal (10.2%), cobalt (9.1%), colophony (9.1%), paraphenylenediamine (8.3%), mercury (7.9%), potassium dichromate (7.9%), and nickel (6.4%).⁴

Pediatric Patch Testing Pearls

History of Product Use
From diapers to drama club, pediatric exposures and sources of ACD are not the same as those seen in adults. Because obtaining a medical history from a toddler can be exasperating, the patient’s caregivers should be asked about potential exposures, ranging from personal care products and diapers to school activities, hobbies, and sports.^5,6 It is important to keep in mind that the patient’s primary caregiver may not be the only individual who applies products to the child.⁷

Application of Allergens
Children are not merely small adults, but they usually do have smaller backs than adult patients. This reduced surface area means that the patch tester must carefully select the allergens to be patch tested. For reference, the back of a typical 6-year-old child can fit 40 to 60 allergens during patch testing.⁸

Patch Test Chambers
In children, the use of plastic patch test chambers may be preferred over aluminum chambers. Children with persistent pruritic subcutaneous nodules induced by aluminum-based vaccines also may have delayed-type sensitivity reactions to aluminum.⁹ These patients could react to the aluminum present in some patch test chambers, making interpretation of the results difficult. The authors (A.R.A. and M.R.) typically use plastic chambers in the pediatric population.

Managing Expectations
As with other procedures in the pediatric population, patch testing can elicit emotions of fear, anxiety, and distrust. Video distraction and/or role-playing games may help capture the attention of children and can be particularly helpful during patch application. Children may be apprehensive about the term allergy testing if they are familiar with the term needle testing from previous allergies.⁵

Securing Patches
Young children can be quite active, posing another challenge for keeping patches in place. We recommend using extra tape to secure the patches in place on a child’s back. In addition, a large transparent film dressing (ie, 12×8 in) can be used if quick application is needed. For extra precaution, the use of a tight T-shirt or favorite onesie during the patch test process may be helpful, making it more difficult for little fingers to remove tape edges.

Duration of Patch Testing
Some authors have proposed application of patch tests for 24 hours in pediatric patients, as compared to 48 hours in adults.¹⁰ This recommendation is based on a theory that the reduced application period will decrease the risk for irritant reactions in pediatric patients.

Pediatric Patch Test Screening Series

A summary of the published screening series for patch testing in the pediatric population is provided (Table).

The T.R.U.E. Test (SmartPractice) is approved by the US Food and Drug Administration for use in patients 6 years and older¹¹; however, it may not adequately represent allergen exposures in the pediatric population. Brankov and Jacob¹⁴ found that 10 (40%) of their proposed top 25 pediatric allergens were not detected using the T.R.U.E. Test.

In 2014, the North American Pediatric Patch Test Series was proposed as a basic screening panel for children aged 6 to 12 years.¹² This series of 20 allergens was developed based on a literature review of pediatric patch test results and case reports as well as a database review. The authors proposed additional allergens to be considered based on patient history.¹²

More recently, a 2017 American Contact Dermatitis Society physician work group proposed the Pediatric Baseline Patch Test Series. This series of 38 allergens for children aged 6 to 18 years was developed based on expert consensus.⁸ Studies to determine the efficacy of this series have yet to be conducted, but it may have high sensitivity in detecting relevant allergens in children as demonstrated by a theoretical detection rate of 84%.¹⁴

There are 2 recommended patch test series for allergic diaper dermatitis.¹⁵ The first series focuses on 23 potential allergens found in wet wipes and topical diaper preparations. The second series contains 10 potential allergens found in diapers. These series contain common topical medications for children including corticosteroids, antimicrobials, and sensitizers specific to diapers such as rubbers and adhesives.¹⁵

Similar to adults, it may be difficult to designate one screening panel that can identify all relevant allergens in children; thus, it is always important to obtain a thorough exposure history and customize testing to suspected allergens and/or patient products based on history and clinical relevance.

Unique Pediatric Allergens

Hobbies
Sports gear such as shin guards and splints often contain allergens such as formaldehyde resin, thiuram mix, and dialkyl thioureas.¹⁶ Perioral dermatitis may be caused by musical instrument mouthpieces containing nickel.⁶

Preservatives
Commonly reported causes of ACD in children include methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) found in wet wipes. A 2016 analysis of diaper wipes showed a low prevalence of MI (6.3%) and MCI (1.6%) in these products, which may reflect the industry’s awareness of these potential allergens and a subsequent change in the preservatives they utilize.¹⁷ However, the prevalence of MCI/MI contact allergy may be on the rise due to the popularity of homemade slime, which is made from common household products such as laundry detergent, dishwashing soap, and liquid glue. The Pediatric Baseline Patch Test Series captures most of the potential allergens in these homemade slime recipes and is recommended for use in pediatric patients suspected of having dermatitis secondary to playing with slime.^8,18

Toilet Seat Dermatitis
Toilet seat dermatitis presents as a pruritic dermatitis on the posterior upper thighs and buttocks. Although most cases of toilet seat dermatitis are irritant rather than allergic, potential allergens include plastics, fragrances, and components of cleaning products. Thus, physicians should maintain a high index of suspicion for ACD to toilet seats.¹⁹

Fragrance and Natural Ingredients
A 2018 study evaluating personal care products marketed specifically for infants and children found that 55% of products (294/533) contained at least 1 common allergen, with fragrance being the most common (48% [255/533]). Other common allergens include betaines (18%), propylene glycol (9%), lanolin (6%), and MCI/MI (3%).²⁰ Caregivers should be advised against the myth that natural products are safer and less allergenic and should be provided with resources such as the Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) for safe alternative personal care products.

Metal Allergens
Nickel, the American Contact Dermatitis Society 2008 Allergen of the Year, is another common allergen that affects children. Nickel allergy, commonly thought to affect the ears due to jewelry and ear piercing, may actually be found in a wide range of daily items such as braces, eyeglasses, keys, zippers, school chairs, electronics, toys, and even food.^3,6,21,22 With increased use of electronics in children of all ages, nickel found in mobile phones and other devices may be of particular concern. Caregivers can use a case or cover for metallic-appearing electronics.

Final Interpretation

Pediatric ACD is common. With limited surface area for patch testing in children, we recommend customized panels based on patient history and exposure. It is important for clinicians to recognize the unique causes of ACD in children and develop age-appropriate management plans.

The pediatric population has a unique product exposure profile due to the many care products specifically marketed for use in children. In fact, the prevalence of allergic contact dermatitis (ACD) in children may be as high as 24.5% in the United States.¹ In patch tested children, relevant positive reaction rates of 56.7% and 48% have been reported by the North American Contact Dermatitis Group and the Pediatric Contact Dermatitis Registry, respectively.^2,3 In this article, we provide an overview of current trends in pediatric patch testing as well as specific considerations in this patient population.

Patch Test Reactions in Children

Several publications have documented pediatric patch test reactions. The North American Contact Dermatitis Group reported patch test results in 883 children from the United States and Canada (2005-2012).² The most common reactions were nickel (28.1%), cobalt (12.3%), neomycin (7.1%), balsam of Peru (5.7%), lanolin (5.5%), and fragrance mix I (5.2%). When compared to adults, children were more likely to have relevant positive patch tests to nickel, cobalt, and compositae mix.² In comparison, data from the Pediatric Contact Dermatitis Registry showed that the most common reactions in 1142 children in the United States (2015-2016) were nickel (22%), fragrance mix I (11%), cobalt (9.1%), balsam of Peru (8.4%), neomycin (7.2%), and propylene glycol (6.8%).³

Allergen sensitivities may vary based on geographic region. In Spain, children showed the highest sensitivities to thiomersal (10.2%), cobalt (9.1%), colophony (9.1%), paraphenylenediamine (8.3%), mercury (7.9%), potassium dichromate (7.9%), and nickel (6.4%).⁴

Pediatric Patch Testing Pearls

History of Product Use
From diapers to drama club, pediatric exposures and sources of ACD are not the same as those seen in adults. Because obtaining a medical history from a toddler can be exasperating, the patient’s caregivers should be asked about potential exposures, ranging from personal care products and diapers to school activities, hobbies, and sports.^5,6 It is important to keep in mind that the patient’s primary caregiver may not be the only individual who applies products to the child.⁷

Application of Allergens
Children are not merely small adults, but they usually do have smaller backs than adult patients. This reduced surface area means that the patch tester must carefully select the allergens to be patch tested. For reference, the back of a typical 6-year-old child can fit 40 to 60 allergens during patch testing.⁸

Patch Test Chambers
In children, the use of plastic patch test chambers may be preferred over aluminum chambers. Children with persistent pruritic subcutaneous nodules induced by aluminum-based vaccines also may have delayed-type sensitivity reactions to aluminum.⁹ These patients could react to the aluminum present in some patch test chambers, making interpretation of the results difficult. The authors (A.R.A. and M.R.) typically use plastic chambers in the pediatric population.

Managing Expectations
As with other procedures in the pediatric population, patch testing can elicit emotions of fear, anxiety, and distrust. Video distraction and/or role-playing games may help capture the attention of children and can be particularly helpful during patch application. Children may be apprehensive about the term allergy testing if they are familiar with the term needle testing from previous allergies.⁵

Securing Patches
Young children can be quite active, posing another challenge for keeping patches in place. We recommend using extra tape to secure the patches in place on a child’s back. In addition, a large transparent film dressing (ie, 12×8 in) can be used if quick application is needed. For extra precaution, the use of a tight T-shirt or favorite onesie during the patch test process may be helpful, making it more difficult for little fingers to remove tape edges.

Duration of Patch Testing
Some authors have proposed application of patch tests for 24 hours in pediatric patients, as compared to 48 hours in adults.¹⁰ This recommendation is based on a theory that the reduced application period will decrease the risk for irritant reactions in pediatric patients.

Pediatric Patch Test Screening Series

A summary of the published screening series for patch testing in the pediatric population is provided (Table).

The T.R.U.E. Test (SmartPractice) is approved by the US Food and Drug Administration for use in patients 6 years and older¹¹; however, it may not adequately represent allergen exposures in the pediatric population. Brankov and Jacob¹⁴ found that 10 (40%) of their proposed top 25 pediatric allergens were not detected using the T.R.U.E. Test.

In 2014, the North American Pediatric Patch Test Series was proposed as a basic screening panel for children aged 6 to 12 years.¹² This series of 20 allergens was developed based on a literature review of pediatric patch test results and case reports as well as a database review. The authors proposed additional allergens to be considered based on patient history.¹²

More recently, a 2017 American Contact Dermatitis Society physician work group proposed the Pediatric Baseline Patch Test Series. This series of 38 allergens for children aged 6 to 18 years was developed based on expert consensus.⁸ Studies to determine the efficacy of this series have yet to be conducted, but it may have high sensitivity in detecting relevant allergens in children as demonstrated by a theoretical detection rate of 84%.¹⁴

There are 2 recommended patch test series for allergic diaper dermatitis.¹⁵ The first series focuses on 23 potential allergens found in wet wipes and topical diaper preparations. The second series contains 10 potential allergens found in diapers. These series contain common topical medications for children including corticosteroids, antimicrobials, and sensitizers specific to diapers such as rubbers and adhesives.¹⁵

Similar to adults, it may be difficult to designate one screening panel that can identify all relevant allergens in children; thus, it is always important to obtain a thorough exposure history and customize testing to suspected allergens and/or patient products based on history and clinical relevance.

Unique Pediatric Allergens

Hobbies
Sports gear such as shin guards and splints often contain allergens such as formaldehyde resin, thiuram mix, and dialkyl thioureas.¹⁶ Perioral dermatitis may be caused by musical instrument mouthpieces containing nickel.⁶

Preservatives
Commonly reported causes of ACD in children include methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) found in wet wipes. A 2016 analysis of diaper wipes showed a low prevalence of MI (6.3%) and MCI (1.6%) in these products, which may reflect the industry’s awareness of these potential allergens and a subsequent change in the preservatives they utilize.¹⁷ However, the prevalence of MCI/MI contact allergy may be on the rise due to the popularity of homemade slime, which is made from common household products such as laundry detergent, dishwashing soap, and liquid glue. The Pediatric Baseline Patch Test Series captures most of the potential allergens in these homemade slime recipes and is recommended for use in pediatric patients suspected of having dermatitis secondary to playing with slime.^8,18

Toilet Seat Dermatitis
Toilet seat dermatitis presents as a pruritic dermatitis on the posterior upper thighs and buttocks. Although most cases of toilet seat dermatitis are irritant rather than allergic, potential allergens include plastics, fragrances, and components of cleaning products. Thus, physicians should maintain a high index of suspicion for ACD to toilet seats.¹⁹

Fragrance and Natural Ingredients
A 2018 study evaluating personal care products marketed specifically for infants and children found that 55% of products (294/533) contained at least 1 common allergen, with fragrance being the most common (48% [255/533]). Other common allergens include betaines (18%), propylene glycol (9%), lanolin (6%), and MCI/MI (3%).²⁰ Caregivers should be advised against the myth that natural products are safer and less allergenic and should be provided with resources such as the Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) for safe alternative personal care products.

Metal Allergens
Nickel, the American Contact Dermatitis Society 2008 Allergen of the Year, is another common allergen that affects children. Nickel allergy, commonly thought to affect the ears due to jewelry and ear piercing, may actually be found in a wide range of daily items such as braces, eyeglasses, keys, zippers, school chairs, electronics, toys, and even food.^3,6,21,22 With increased use of electronics in children of all ages, nickel found in mobile phones and other devices may be of particular concern. Caregivers can use a case or cover for metallic-appearing electronics.

Final Interpretation

Pediatric ACD is common. With limited surface area for patch testing in children, we recommend customized panels based on patient history and exposure. It is important for clinicians to recognize the unique causes of ACD in children and develop age-appropriate management plans.

The pediatric population has a unique product exposure profile due to the many care products specifically marketed for use in children. In fact, the prevalence of allergic contact dermatitis (ACD) in children may be as high as 24.5% in the United States.¹ In patch tested children, relevant positive reaction rates of 56.7% and 48% have been reported by the North American Contact Dermatitis Group and the Pediatric Contact Dermatitis Registry, respectively.^2,3 In this article, we provide an overview of current trends in pediatric patch testing as well as specific considerations in this patient population.

Patch Test Reactions in Children

Several publications have documented pediatric patch test reactions. The North American Contact Dermatitis Group reported patch test results in 883 children from the United States and Canada (2005-2012).² The most common reactions were nickel (28.1%), cobalt (12.3%), neomycin (7.1%), balsam of Peru (5.7%), lanolin (5.5%), and fragrance mix I (5.2%). When compared to adults, children were more likely to have relevant positive patch tests to nickel, cobalt, and compositae mix.² In comparison, data from the Pediatric Contact Dermatitis Registry showed that the most common reactions in 1142 children in the United States (2015-2016) were nickel (22%), fragrance mix I (11%), cobalt (9.1%), balsam of Peru (8.4%), neomycin (7.2%), and propylene glycol (6.8%).³

Allergen sensitivities may vary based on geographic region. In Spain, children showed the highest sensitivities to thiomersal (10.2%), cobalt (9.1%), colophony (9.1%), paraphenylenediamine (8.3%), mercury (7.9%), potassium dichromate (7.9%), and nickel (6.4%).⁴

Pediatric Patch Testing Pearls

History of Product Use
From diapers to drama club, pediatric exposures and sources of ACD are not the same as those seen in adults. Because obtaining a medical history from a toddler can be exasperating, the patient’s caregivers should be asked about potential exposures, ranging from personal care products and diapers to school activities, hobbies, and sports.^5,6 It is important to keep in mind that the patient’s primary caregiver may not be the only individual who applies products to the child.⁷

Application of Allergens
Children are not merely small adults, but they usually do have smaller backs than adult patients. This reduced surface area means that the patch tester must carefully select the allergens to be patch tested. For reference, the back of a typical 6-year-old child can fit 40 to 60 allergens during patch testing.⁸

Patch Test Chambers
In children, the use of plastic patch test chambers may be preferred over aluminum chambers. Children with persistent pruritic subcutaneous nodules induced by aluminum-based vaccines also may have delayed-type sensitivity reactions to aluminum.⁹ These patients could react to the aluminum present in some patch test chambers, making interpretation of the results difficult. The authors (A.R.A. and M.R.) typically use plastic chambers in the pediatric population.

Managing Expectations
As with other procedures in the pediatric population, patch testing can elicit emotions of fear, anxiety, and distrust. Video distraction and/or role-playing games may help capture the attention of children and can be particularly helpful during patch application. Children may be apprehensive about the term allergy testing if they are familiar with the term needle testing from previous allergies.⁵

Securing Patches
Young children can be quite active, posing another challenge for keeping patches in place. We recommend using extra tape to secure the patches in place on a child’s back. In addition, a large transparent film dressing (ie, 12×8 in) can be used if quick application is needed. For extra precaution, the use of a tight T-shirt or favorite onesie during the patch test process may be helpful, making it more difficult for little fingers to remove tape edges.

Duration of Patch Testing
Some authors have proposed application of patch tests for 24 hours in pediatric patients, as compared to 48 hours in adults.¹⁰ This recommendation is based on a theory that the reduced application period will decrease the risk for irritant reactions in pediatric patients.

Pediatric Patch Test Screening Series

A summary of the published screening series for patch testing in the pediatric population is provided (Table).

The T.R.U.E. Test (SmartPractice) is approved by the US Food and Drug Administration for use in patients 6 years and older¹¹; however, it may not adequately represent allergen exposures in the pediatric population. Brankov and Jacob¹⁴ found that 10 (40%) of their proposed top 25 pediatric allergens were not detected using the T.R.U.E. Test.

In 2014, the North American Pediatric Patch Test Series was proposed as a basic screening panel for children aged 6 to 12 years.¹² This series of 20 allergens was developed based on a literature review of pediatric patch test results and case reports as well as a database review. The authors proposed additional allergens to be considered based on patient history.¹²

More recently, a 2017 American Contact Dermatitis Society physician work group proposed the Pediatric Baseline Patch Test Series. This series of 38 allergens for children aged 6 to 18 years was developed based on expert consensus.⁸ Studies to determine the efficacy of this series have yet to be conducted, but it may have high sensitivity in detecting relevant allergens in children as demonstrated by a theoretical detection rate of 84%.¹⁴

There are 2 recommended patch test series for allergic diaper dermatitis.¹⁵ The first series focuses on 23 potential allergens found in wet wipes and topical diaper preparations. The second series contains 10 potential allergens found in diapers. These series contain common topical medications for children including corticosteroids, antimicrobials, and sensitizers specific to diapers such as rubbers and adhesives.¹⁵

Similar to adults, it may be difficult to designate one screening panel that can identify all relevant allergens in children; thus, it is always important to obtain a thorough exposure history and customize testing to suspected allergens and/or patient products based on history and clinical relevance.

Unique Pediatric Allergens

Hobbies
Sports gear such as shin guards and splints often contain allergens such as formaldehyde resin, thiuram mix, and dialkyl thioureas.¹⁶ Perioral dermatitis may be caused by musical instrument mouthpieces containing nickel.⁶

Preservatives
Commonly reported causes of ACD in children include methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) found in wet wipes. A 2016 analysis of diaper wipes showed a low prevalence of MI (6.3%) and MCI (1.6%) in these products, which may reflect the industry’s awareness of these potential allergens and a subsequent change in the preservatives they utilize.¹⁷ However, the prevalence of MCI/MI contact allergy may be on the rise due to the popularity of homemade slime, which is made from common household products such as laundry detergent, dishwashing soap, and liquid glue. The Pediatric Baseline Patch Test Series captures most of the potential allergens in these homemade slime recipes and is recommended for use in pediatric patients suspected of having dermatitis secondary to playing with slime.^8,18

Toilet Seat Dermatitis
Toilet seat dermatitis presents as a pruritic dermatitis on the posterior upper thighs and buttocks. Although most cases of toilet seat dermatitis are irritant rather than allergic, potential allergens include plastics, fragrances, and components of cleaning products. Thus, physicians should maintain a high index of suspicion for ACD to toilet seats.¹⁹

Fragrance and Natural Ingredients
A 2018 study evaluating personal care products marketed specifically for infants and children found that 55% of products (294/533) contained at least 1 common allergen, with fragrance being the most common (48% [255/533]). Other common allergens include betaines (18%), propylene glycol (9%), lanolin (6%), and MCI/MI (3%).²⁰ Caregivers should be advised against the myth that natural products are safer and less allergenic and should be provided with resources such as the Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) for safe alternative personal care products.

Metal Allergens
Nickel, the American Contact Dermatitis Society 2008 Allergen of the Year, is another common allergen that affects children. Nickel allergy, commonly thought to affect the ears due to jewelry and ear piercing, may actually be found in a wide range of daily items such as braces, eyeglasses, keys, zippers, school chairs, electronics, toys, and even food.^3,6,21,22 With increased use of electronics in children of all ages, nickel found in mobile phones and other devices may be of particular concern. Caregivers can use a case or cover for metallic-appearing electronics.

Final Interpretation

Pediatric ACD is common. With limited surface area for patch testing in children, we recommend customized panels based on patient history and exposure. It is important for clinicians to recognize the unique causes of ACD in children and develop age-appropriate management plans.

The Diagnosis: Irritant Contact Dermatitis and Hyperpigmentation Due to Juglone  

Clinical suspicion, resemblance to similar cases, and questioning the patient about his behavior prior to the onset of symptoms led to the diagnosis of irritant contact dermatitis and hyperpigmentation due to juglone in this case. Walnuts belong to the botanical family of Juglandaceae and are the seed of the trees of the genus Juglans, which encompass 24 different species. The nuts from all species included in this genus are edible.¹ The most well-known species of walnut is the common walnut (Juglans regia), which is native to the Balkans region in southeast Europe, southwest and central Asia extending to the Himalayas, and southwest China.¹  

Walnut fruits are rich in phenolic compounds. Thirteen phenolic compounds have been identified in walnut husks including chlorogenic acid, caffeic acid, ferulic acid, sinapic acid, gallic acid, ellagic acid, protocatechuic acid, syringic acid, vanillic acid, catechin, epicatechin, myricetin, and juglone.² Juglone, also called 5-hydroxy-1,4-napthoquinone, is a yellow naphthoquinone pigment that occurs naturally in the leaves, roots, husks, and bark of plants in the Juglandaceae family, particularly the black walnut (Juglans nigra).^3,4 

Juglans regia, also known as English or Persian walnut, contains potent chemical constituents and has been used to treat diverse ailments such as diarrhea, hyperglycemia, cancer, infectious diseases, anorexia, asthma, helminthiasis, arthritis, sinusitis, stomachache, and skin disorders (eg, eczema; acne; alopecia; scalp itching, peeling, and dandruff), and as an adjunctive emollient and itch-relieving treatment.^5,6 

The juice of walnut shells from the J regia tree have been used for centuries to color the skin and hair.⁷ Irritation and skin hyperpigmentation have been associated with topical walnut use.⁵ As a naphthoquinone, juglone also is reported to exert some toxic effects on normal tissues including acute irritant contact dermatitis.⁴ As the active ingredient from the green husk of walnuts, it has been considered a strong sensitizer in guinea pigs,¹ but contact sensitivity in humans rarely has been reported.⁷  

Juglone is known to react with the keratin proteins present in the skin to form sclerojuglonic compounds, which have UV protection properties and a red-brown color.⁸ The resulting reaction gives rise to chromophore groups with a strong pigmenting action that absorbs visible colors (especially violet) and reflects yellow and red, resulting in the coloration ranging from red to deep brown.⁷ The mechanism of skin pigmentation does not involve the melanocytes. Hyperchromia involving the hands--particularly the palms, fingers, and nails--lasts 1 to 4 weeks depending on the intensity of the pigmentation. Housewives and agricultural workers are the at-risk population.⁷ Acute irritant contact dermatitis and hyperpigmentation due to juglone mainly has been observed during the early autumn in agricultural workers and housewives who remove the green husk of walnuts.⁹  

Addison disease can present with pigmentary changes in the skin and mucous membranes; it also is accompanied by fatigue, anorexia, weakness, and weight loss, none of which were noted in our patient. A fixed drug eruption tends to have an annular or oval form and is related to the intake of medication (mostly antibiotics) up to 2 weeks prior to the onset of the dermatosis. Our patient did not have any chronic disease or take any medication prior to the dermatosis and lacked the classic clinical morphology of this entity. Hemochromatosis affects not only the skin but also the liver, myocardial fibers, and other internal organs. Our patient did not have any clinical manifestations of liver or heart failure or diabetes mellitus.  

Our patient was treated with drainage of the blisters. Due to the extent of the dermatosis, prednisone 25 mg/d also was initiated. The patient was instructed to avoid direct contact with the husk of walnuts. At 1-month follow-up, the hyperpigmentation had resolved with no relapse (Figure). 

The Diagnosis: Irritant Contact Dermatitis and Hyperpigmentation Due to Juglone  

Clinical suspicion, resemblance to similar cases, and questioning the patient about his behavior prior to the onset of symptoms led to the diagnosis of irritant contact dermatitis and hyperpigmentation due to juglone in this case. Walnuts belong to the botanical family of Juglandaceae and are the seed of the trees of the genus Juglans, which encompass 24 different species. The nuts from all species included in this genus are edible.¹ The most well-known species of walnut is the common walnut (Juglans regia), which is native to the Balkans region in southeast Europe, southwest and central Asia extending to the Himalayas, and southwest China.¹  

Walnut fruits are rich in phenolic compounds. Thirteen phenolic compounds have been identified in walnut husks including chlorogenic acid, caffeic acid, ferulic acid, sinapic acid, gallic acid, ellagic acid, protocatechuic acid, syringic acid, vanillic acid, catechin, epicatechin, myricetin, and juglone.² Juglone, also called 5-hydroxy-1,4-napthoquinone, is a yellow naphthoquinone pigment that occurs naturally in the leaves, roots, husks, and bark of plants in the Juglandaceae family, particularly the black walnut (Juglans nigra).^3,4 

Juglans regia, also known as English or Persian walnut, contains potent chemical constituents and has been used to treat diverse ailments such as diarrhea, hyperglycemia, cancer, infectious diseases, anorexia, asthma, helminthiasis, arthritis, sinusitis, stomachache, and skin disorders (eg, eczema; acne; alopecia; scalp itching, peeling, and dandruff), and as an adjunctive emollient and itch-relieving treatment.^5,6 

The juice of walnut shells from the J regia tree have been used for centuries to color the skin and hair.⁷ Irritation and skin hyperpigmentation have been associated with topical walnut use.⁵ As a naphthoquinone, juglone also is reported to exert some toxic effects on normal tissues including acute irritant contact dermatitis.⁴ As the active ingredient from the green husk of walnuts, it has been considered a strong sensitizer in guinea pigs,¹ but contact sensitivity in humans rarely has been reported.⁷  

Juglone is known to react with the keratin proteins present in the skin to form sclerojuglonic compounds, which have UV protection properties and a red-brown color.⁸ The resulting reaction gives rise to chromophore groups with a strong pigmenting action that absorbs visible colors (especially violet) and reflects yellow and red, resulting in the coloration ranging from red to deep brown.⁷ The mechanism of skin pigmentation does not involve the melanocytes. Hyperchromia involving the hands--particularly the palms, fingers, and nails--lasts 1 to 4 weeks depending on the intensity of the pigmentation. Housewives and agricultural workers are the at-risk population.⁷ Acute irritant contact dermatitis and hyperpigmentation due to juglone mainly has been observed during the early autumn in agricultural workers and housewives who remove the green husk of walnuts.⁹  

Addison disease can present with pigmentary changes in the skin and mucous membranes; it also is accompanied by fatigue, anorexia, weakness, and weight loss, none of which were noted in our patient. A fixed drug eruption tends to have an annular or oval form and is related to the intake of medication (mostly antibiotics) up to 2 weeks prior to the onset of the dermatosis. Our patient did not have any chronic disease or take any medication prior to the dermatosis and lacked the classic clinical morphology of this entity. Hemochromatosis affects not only the skin but also the liver, myocardial fibers, and other internal organs. Our patient did not have any clinical manifestations of liver or heart failure or diabetes mellitus.  

Our patient was treated with drainage of the blisters. Due to the extent of the dermatosis, prednisone 25 mg/d also was initiated. The patient was instructed to avoid direct contact with the husk of walnuts. At 1-month follow-up, the hyperpigmentation had resolved with no relapse (Figure). 

The Diagnosis: Irritant Contact Dermatitis and Hyperpigmentation Due to Juglone  

Clinical suspicion, resemblance to similar cases, and questioning the patient about his behavior prior to the onset of symptoms led to the diagnosis of irritant contact dermatitis and hyperpigmentation due to juglone in this case. Walnuts belong to the botanical family of Juglandaceae and are the seed of the trees of the genus Juglans, which encompass 24 different species. The nuts from all species included in this genus are edible.¹ The most well-known species of walnut is the common walnut (Juglans regia), which is native to the Balkans region in southeast Europe, southwest and central Asia extending to the Himalayas, and southwest China.¹  

Walnut fruits are rich in phenolic compounds. Thirteen phenolic compounds have been identified in walnut husks including chlorogenic acid, caffeic acid, ferulic acid, sinapic acid, gallic acid, ellagic acid, protocatechuic acid, syringic acid, vanillic acid, catechin, epicatechin, myricetin, and juglone.² Juglone, also called 5-hydroxy-1,4-napthoquinone, is a yellow naphthoquinone pigment that occurs naturally in the leaves, roots, husks, and bark of plants in the Juglandaceae family, particularly the black walnut (Juglans nigra).^3,4 

Juglans regia, also known as English or Persian walnut, contains potent chemical constituents and has been used to treat diverse ailments such as diarrhea, hyperglycemia, cancer, infectious diseases, anorexia, asthma, helminthiasis, arthritis, sinusitis, stomachache, and skin disorders (eg, eczema; acne; alopecia; scalp itching, peeling, and dandruff), and as an adjunctive emollient and itch-relieving treatment.^5,6 

The juice of walnut shells from the J regia tree have been used for centuries to color the skin and hair.⁷ Irritation and skin hyperpigmentation have been associated with topical walnut use.⁵ As a naphthoquinone, juglone also is reported to exert some toxic effects on normal tissues including acute irritant contact dermatitis.⁴ As the active ingredient from the green husk of walnuts, it has been considered a strong sensitizer in guinea pigs,¹ but contact sensitivity in humans rarely has been reported.⁷  

Juglone is known to react with the keratin proteins present in the skin to form sclerojuglonic compounds, which have UV protection properties and a red-brown color.⁸ The resulting reaction gives rise to chromophore groups with a strong pigmenting action that absorbs visible colors (especially violet) and reflects yellow and red, resulting in the coloration ranging from red to deep brown.⁷ The mechanism of skin pigmentation does not involve the melanocytes. Hyperchromia involving the hands--particularly the palms, fingers, and nails--lasts 1 to 4 weeks depending on the intensity of the pigmentation. Housewives and agricultural workers are the at-risk population.⁷ Acute irritant contact dermatitis and hyperpigmentation due to juglone mainly has been observed during the early autumn in agricultural workers and housewives who remove the green husk of walnuts.⁹  

Addison disease can present with pigmentary changes in the skin and mucous membranes; it also is accompanied by fatigue, anorexia, weakness, and weight loss, none of which were noted in our patient. A fixed drug eruption tends to have an annular or oval form and is related to the intake of medication (mostly antibiotics) up to 2 weeks prior to the onset of the dermatosis. Our patient did not have any chronic disease or take any medication prior to the dermatosis and lacked the classic clinical morphology of this entity. Hemochromatosis affects not only the skin but also the liver, myocardial fibers, and other internal organs. Our patient did not have any clinical manifestations of liver or heart failure or diabetes mellitus.  

Our patient was treated with drainage of the blisters. Due to the extent of the dermatosis, prednisone 25 mg/d also was initiated. The patient was instructed to avoid direct contact with the husk of walnuts. At 1-month follow-up, the hyperpigmentation had resolved with no relapse (Figure). 

The Diagnosis: Irritant Contact Dermatitis  

A slang term for volatile alkyl nitrites, poppers are inhaled for recreational purposes. They produce    rapid-onset euphoria and sexual arousal, as well as relax anal and vaginal sphincters, facilitating sexual intercourse. Alkyl nitrites initially were developed to treat coronary disease and angina but were replaced by more potent drugs.¹ Because of their psychoactive effects and smooth muscle relaxation properties, they are widely used by homosexual and bisexual men.^1-3 The term poppers was originated by the sound generated when the glass vials are crushed; currently, they also may be found in other formats.¹  

Nausea, hypotension, and headache are mild common adverse effects of volatile alkyl nitrites¹; cardiac arrhythmia, oxidative hemolysis,⁴ and poppers maculopathy^5,6 with permanent eye damage also have been reported.⁷ On the skin, volatile alkyl nitrites induce irritant contact dermatitis that heals without scarring, characteristically involving the face and upper thoracic region, as they are volatile vapors.² However, the reaction can occur elsewhere. There have been reports of contact dermatitis on other locations, such as the thigh or the ankle, due to vials broken while stored in pockets or on the cuff of the socks.¹ There also is a report of irritant contact dermatitis manifesting as a penile ulcer.³ Albeit rare, allergic contact dermatitis to volatile alkyl nitrites and other nitrites also can occur.⁸  

The abuse of alkyl nitrites may increase the risk for sexually transmitted infections (STIs), as they may decrease safer sexual practices and increase the propensity to engage in risky sexual behavior. It has been suggested to screen for STIs in patients with history of volatile alkyl nitrite use. In the past, volatile alkyl nitrites were believed to be a potential vector of human immunodeficiency virus.⁹ Other popular drugs used in social context or "club drugs," such as 3,4-methylenedioxymethamphetamine, gamma hydroxybutyrate, methamphetamine, and ketamine, do not produce irritant dermatitis as an adverse cutaneous reaction.¹⁰ The differential diagnosis in our patient included herpes simplex virus and contagious impetigo¹ as well as bullous lupus erythematosus and periorificial dermatitis; however, the clinical picture, acute onset of the reaction, and the patient's medical history were critical in making the correct diagnosis.  

The patient was treated with topical hydrocortisone and fusidic acid cream twice daily for 7 days with complete response. Sexually transmitted infection screening was unremarkable. We suggest performing an STI workup on patients with history of volatile alkyl nitrite use. 

The Diagnosis: Irritant Contact Dermatitis  

A slang term for volatile alkyl nitrites, poppers are inhaled for recreational purposes. They produce    rapid-onset euphoria and sexual arousal, as well as relax anal and vaginal sphincters, facilitating sexual intercourse. Alkyl nitrites initially were developed to treat coronary disease and angina but were replaced by more potent drugs.¹ Because of their psychoactive effects and smooth muscle relaxation properties, they are widely used by homosexual and bisexual men.^1-3 The term poppers was originated by the sound generated when the glass vials are crushed; currently, they also may be found in other formats.¹  

Nausea, hypotension, and headache are mild common adverse effects of volatile alkyl nitrites¹; cardiac arrhythmia, oxidative hemolysis,⁴ and poppers maculopathy^5,6 with permanent eye damage also have been reported.⁷ On the skin, volatile alkyl nitrites induce irritant contact dermatitis that heals without scarring, characteristically involving the face and upper thoracic region, as they are volatile vapors.² However, the reaction can occur elsewhere. There have been reports of contact dermatitis on other locations, such as the thigh or the ankle, due to vials broken while stored in pockets or on the cuff of the socks.¹ There also is a report of irritant contact dermatitis manifesting as a penile ulcer.³ Albeit rare, allergic contact dermatitis to volatile alkyl nitrites and other nitrites also can occur.⁸  

The abuse of alkyl nitrites may increase the risk for sexually transmitted infections (STIs), as they may decrease safer sexual practices and increase the propensity to engage in risky sexual behavior. It has been suggested to screen for STIs in patients with history of volatile alkyl nitrite use. In the past, volatile alkyl nitrites were believed to be a potential vector of human immunodeficiency virus.⁹ Other popular drugs used in social context or "club drugs," such as 3,4-methylenedioxymethamphetamine, gamma hydroxybutyrate, methamphetamine, and ketamine, do not produce irritant dermatitis as an adverse cutaneous reaction.¹⁰ The differential diagnosis in our patient included herpes simplex virus and contagious impetigo¹ as well as bullous lupus erythematosus and periorificial dermatitis; however, the clinical picture, acute onset of the reaction, and the patient's medical history were critical in making the correct diagnosis.  

The patient was treated with topical hydrocortisone and fusidic acid cream twice daily for 7 days with complete response. Sexually transmitted infection screening was unremarkable. We suggest performing an STI workup on patients with history of volatile alkyl nitrite use. 

The Diagnosis: Irritant Contact Dermatitis  

A slang term for volatile alkyl nitrites, poppers are inhaled for recreational purposes. They produce    rapid-onset euphoria and sexual arousal, as well as relax anal and vaginal sphincters, facilitating sexual intercourse. Alkyl nitrites initially were developed to treat coronary disease and angina but were replaced by more potent drugs.¹ Because of their psychoactive effects and smooth muscle relaxation properties, they are widely used by homosexual and bisexual men.^1-3 The term poppers was originated by the sound generated when the glass vials are crushed; currently, they also may be found in other formats.¹  

Nausea, hypotension, and headache are mild common adverse effects of volatile alkyl nitrites¹; cardiac arrhythmia, oxidative hemolysis,⁴ and poppers maculopathy^5,6 with permanent eye damage also have been reported.⁷ On the skin, volatile alkyl nitrites induce irritant contact dermatitis that heals without scarring, characteristically involving the face and upper thoracic region, as they are volatile vapors.² However, the reaction can occur elsewhere. There have been reports of contact dermatitis on other locations, such as the thigh or the ankle, due to vials broken while stored in pockets or on the cuff of the socks.¹ There also is a report of irritant contact dermatitis manifesting as a penile ulcer.³ Albeit rare, allergic contact dermatitis to volatile alkyl nitrites and other nitrites also can occur.⁸  

The abuse of alkyl nitrites may increase the risk for sexually transmitted infections (STIs), as they may decrease safer sexual practices and increase the propensity to engage in risky sexual behavior. It has been suggested to screen for STIs in patients with history of volatile alkyl nitrite use. In the past, volatile alkyl nitrites were believed to be a potential vector of human immunodeficiency virus.⁹ Other popular drugs used in social context or "club drugs," such as 3,4-methylenedioxymethamphetamine, gamma hydroxybutyrate, methamphetamine, and ketamine, do not produce irritant dermatitis as an adverse cutaneous reaction.¹⁰ The differential diagnosis in our patient included herpes simplex virus and contagious impetigo¹ as well as bullous lupus erythematosus and periorificial dermatitis; however, the clinical picture, acute onset of the reaction, and the patient's medical history were critical in making the correct diagnosis.  

The patient was treated with topical hydrocortisone and fusidic acid cream twice daily for 7 days with complete response. Sexually transmitted infection screening was unremarkable. We suggest performing an STI workup on patients with history of volatile alkyl nitrite use.