Swimming pool contact dermatitis caused by 1-bromo-3-chloro-5,5-dimethyl hydantoin.

Background. Bromo-3-chloro-5,5-dimethylhydantoin (BCDMH) is a chemical used as a disinfectant for recreational water. BCDMH was described as being responsible for an epidemic of irritant contact dermatitis in the UK (1983), and its sensitizing capacity was also discussed. Objectives. The aim of this study was to assess whether BCDMH used to disinfect swimming pools and spas can cause allergic contact dermatitis among its users. Methods. Ten patients suffering from dermatitis associated with using swimming pools disinfected with BCDMH and 40 controls were studied. Several dilutions of BCDMH, 10% to 1 ppm, were patch tested. Results. All 10 patients studied showed a positive patch test reaction to BCDMH 1% in petrolatum. At least one case showed occupational relevance, with a positive reaction even at 1 ppm. Conclusion. On the basis of the clinical findings, the positive patch test reactions to BCDMH, and the negative patch test reactions in controls, the suggested diagnosis was allergic contact dermatitis caused by BCDMH used as a disinfectant in the swimming pool water. Contact allergy should be taken into consideration when patients suffer from swimming pool-associated itchy dermatitis.