Allergic contact dermatitis may contribute to greater atopic dermatitis severity among patients with skin of color, according to a scoping review published in the International Journal of Women’s Dermatology.
Connecticut-based researchers reviewed eight studies of patients with skin of color referred for patch testing to evaluate the prevalence of atopic dermatitis and patterns of allergen sensitization in this population. Across included studies, adults referred for patch testing had higher rates of atopic dermatitis compared with the estimated ten percent prevalence in the general US adult population. Reported rates ranged from 21% to 38% among Black adults, approximately 26% among Hispanic adults, and 33% among Asian adults. Among pediatric patients referred for patch testing, 49% to 67% had a diagnosis of atopic dermatitis.
Four of the eight studies suggested higher eczema prevalence among non-White patients referred for patch testing compared with White patients, although statistical significance was not consistently reported. In a North American Contact Dermatitis Group review of more than 19,000 patients, 13% of Black patients vs 9% of White patients had a history of atopic dermatitis. Black patients were more likely to have positive reactions to certain allergens, including p-phenylenediamine.
Other analyses identified group-specific sensitization patterns. In one retrospective review, Asian patients had higher rates of sensitization to cinnamic aldehyde, colophony, and nickel compared with White patients. Pediatric registry data showed that Asian and Black children referred for patch testing were more likely to have concurrent atopic dermatitis and more severe disease compared with White children.
The review also identified disparities in access to patch testing. Black patients comprise 13% of the US population but represent 5% of patients undergoing patch testing. Hispanic patients account for 16% of the population but 2% of those tested. Limited access may delay identification of contact allergens that exacerbate atopic dermatitis.
Allergen exposure patterns differed across groups. Studies cited in the review reported that commonly used hair care products among Black patients, including chemical relaxers and synthetic hair products, contain potential contact allergens. One retrospective review also found higher occupational allergen exposure among Black male patients compared with other groups.
The authors noted that most included studies were retrospective and heterogeneous and that causality between allergic contact dermatitis and atopic dermatitis severity could not be established. They concluded that physicians should consider contact allergy in patients with skin of color who have persistent or treatment-resistant atopic dermatitis and consider referral for patch testing when appropriate
The study was led by Janelle R. Mallett, MD, MBA, of the University of Connecticut, and Camilla M. Lee, BS, of Quinnipiac University. The authors reported no conflicts of interest.