Patch testing with ammonium persulfate: The North American Contact Dermatitis Group Experience, 2015-2018.

Background Ammonium persulfate (APS), an oxidizing agent used in hair products, manufacturing, and pool/spa water, can cause skin reactions, including allergic contact dermatitis. Objective To characterize positive patch test reactions to APS (2.5% petrolatum). Methods Retrospective analysis of patients tested to the North American Contact Dermatitis Group screening series from 2015 to 2018. Results Of 10,526 patients, 193 (1.8%) had positive patch test reactions to APS. Compared with APS-negative patients, APS-positive patients were significantly more likely to be male (43.2% vs 28.0%; P  Limitations Immediate reactions and follow-up testing were not captured. Conclusion The proportion of patients positive to APS was 1.8%. APS positivity was significantly associated with male sex and hand dermatitis. Swimming pool/spa chemicals were important sources of APS exposure.