Allergy to a hot tub water treatment chemical: an unexpectedly common cause of generalized dermatitis in men.

Potassium peroxymonosulfate (PPMS) is a potassium triple salt (2KHSO5 • KHSO4 • K2SO4) that is commonly used as an oxidizing compound in pool and hot tub shock treatments. It is the active ingredient in Oxone® (DuPont), a pool and spa oxidizer. In its disulfate form, PPMS is used in hair-bleaching preparations, flour, and denture cleanser, and has been reported as a cause of contact dermatitis, urticaria, and asthma.1–5 DuPont lists “allergic reactions in sensitive individuals” as a potential health hazard of Oxone in its safety information.6 However, contact dermatitis induced by PPMS used in pools or hot tubs has only been documented in two case reports, both of which involved hot tubs.1,4 In August of 2008, the authors began to question all of their patients with widespread dermatitis about the use of hot tubs, and all patients who used hot tubs were tested for allergy to PPMS. Over the ensuing 12 months, the authors diagnosed six patients with allergy to PPMS used as shock treatment in their hot tubs or pools, all of whom were demographically similar (Figure 1). Figure 1 Severe dermatitis on the lower legs in a patient with allergy to potassium peroxymonosulfate who sat with legs “dangling” in the water Objective The objective of the study was to determine the demographic characteristics of patients diagnosed with allergy to PPMS and determine the likelihood that these characteristics represent a significant finding.