Abstract
Background: Persulfate is an oxidizing agent used for multiple purposes, including bleaching hair, bleaching flour, and as pool/spa water disinfectant. Objective: To identify the prevalence and clinical characteristics of patients allergic to ammonium persulfate (APS) among patients who underwent patch testing in our clinic. Methods: A retrospective chart review of 2138 patients who underwent patch testing at Brigham and Women's hospital in Boston between July 2015 to November 2019. All patients were tested to our standard series including APS 2.5% petrolatum. Given the irritant nature of APS, we included for analysis only patients with 2+ or 3+ reactions. Results: Among 2138 patients, 61 (2.85%) had 2+ or 3+ reactions to APS. In this study, 72% were female. 75% had an atopic diathesis; 56% had 2+ reactions, and 44% had 3+ reactions. Clinical relevance was definite in 11%, probable in 10%, and unknown/possible in 79%. In patients with definite clinical relevance, 6/7 had occupational allergic contact dermatitis: 4 hairdressers, 1 hair salon cleaner, and 1 aquarium worker; 1/7 was bleaching her hair. Conclusion: Prevalence of 2+ or 3+ APS reactions in this single-center study was higher than that reported by the North American Contact Dermatitis Group, 2015-2016, (0.75% vs. 2.85% in our study). APS is an important occupational allergen, and clinicians should be aware of this when treating patients with exposure to APS.