TOPLINE

Patch test results for allergic contact dermatitis (ACD) showed significant differences across racial and ethnic groups, with 13 of 50 allergens tested varying by race and ethnicity.

METHODOLOGY

• Researchers conducted a retrospective cross-sectional analysis of 32,138 patients who underwent patch testing through the North American Contact Dermatitis Group (NACDG) in the US and Canada between 2007 and 2020.
• Patients self-identified as White (86.5%), Asian (6.8%), Black (4.8%), or Hispanic (2.0%).
• Patients were tested with a standardized panel of 50 allergens using NACDG protocols, with final readings performed 72-168 hours after application.
• Analysis examined demographic and clinical characteristics according to male, occupational, atopic, hand, leg, face, age greater than 40 years, and proportion of positivity guidelines, with statistical significance set at P < .001 using the Bonferroni correction.
• Investigators compared allergen positivity and final diagnoses across racial and ethnic groups. Up to three final diagnoses were assigned per patient, including ACD, irritant contact dermatitis, and atopic dermatitis, on the basis of history, physical examination, and patch test results.

TAKEAWAY

• Overall, 62.3% of patients had at least one positive patch test reaction, and 13 allergens showed significant variation across patient groups. Nickel was the most common positive patch test reaction in all groups.
• White patients had the highest positivity for balsam of Peru (8.3% vs 5.1%), neomycin (8.1% vs 6.3%), quaternium-15 (5.5% vs 4.0%), and fragrance mix II (5.1% vs 3.7%) compared with non-White patients (all P < .001). Black patients had the highest positivity for p-phenylenediamine (9.9% vs 5.7%; odds ratio [OR], 1.92), disperse dyes (2.6% vs 1.2%; OR, 2.13), and cobalt (9.7% vs 6.9%; OR, 1.54) compared with non-Black patients.
• Asian patients had the highest positivity for nickel (22.7% vs 17.6%; OR, 1.39), cobalt (11.5% vs 6.7%; OR, 1.86), and thiuram mix (4.8% vs 3.2%; OR, 1.55) compared with non-Asian patients, while Hispanic patients had the highest positivity for propylene glycol (6.0% vs 3.1%; OR, 2.10) compared with non-Hispanic patients.
• Overall, 58.8% of patients were assigned a final diagnosis of ACD, with the highest proportion among White patients (59.4% vs 51.1% in Hispanic patients). Asian patients demonstrated the highest prevalence of atopic dermatitis (21.9% vs 17.8% in White patients).

IN PRACTICE

“The results can help guide identification of clinically relevant allergen exposures in diverse populations, highlighting the importance of considering demographic diversity in clinical practice,” the study authors wrote.

SOURCE

The study was led by Brandon L. Adler, MD, Department of Dermatology, University of Southern California, Los Angeles, and was published online on July 30 in the Journal of the American Academy of Dermatology.

LIMITATIONS

The findings may not be generalizable to the general population or the general dermatology patient population. The study included disproportionately higher numbers of White patients. Race and ethnicity are social constructs that do not accurately reflect biological diversity. Sociocultural and environmental factors could affect the findings. Determination of patch test positivity was subject to clinical judgment, and the follow-up was short.

DISCLOSURES

The study received support from the National Center for Advancing Translational Sciences of the National Institutes of Health. Adler and many authors disclosed serving as research investigators, scientific advisors, or consultants; receiving royalties; and being employed by various companies, including Eli Lilly and Company, AbbVie, Dermavant, and UpToDate. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.