I have a patient who I will be evaluating for a macular pruritic rash that occurred after swimming in an indoor chlorinated pool. She teaches swimming lessons in a local health club. I am aware of the possible risks of chlorine exposure and asthma. However, I could not find anything on chlorine exposure with swimming and rashes. Are you aware of this type of reaction? How could it be evaluated? Skin prick or patch w/ the same water? Your thoughts and help are appreciated.


Thank you for your inquiry.

Of course, there are many different causes for a macular pruritic rash, and a chronological relationship between exposure to the swimming pool and the production of the rash does not automatically indicate that there is a cause and effect relationship. Therefore, one should not assume automatically that her rash was due to exposure to chlorinated water in the pool. However, there are reports of dermatitis related to chlorinated water in pools. Nonetheless, according to my literature search, they are rare. Below, there are three references indicating that contact reactions can occur to the disinfectant used in swimming pools.

However, I was unable to find any standardized workup for patients exhibiting a rash possibly related to chlorinated water. I have never personally seen a case.

Thus, to the best of my knowledge, one would be left to their own resources as to a strategy to evaluate this patient. I think the most logical way to proceed would be to do a challenge to the water in the pool. This can be done once the rash has cleared. Indeed, if there was a relationship between exposure to the chlorinated water in the pool and the rash, symptoms should be gone within two weeks of cessation of exposure. Upon clearing, one could do an isolated challenge.

There are two ways this can be done. One would be to go to the pool itself and expose a small portion of the body (hand and upper forearm, for example) to the pool water for the same duration of time that the patient was exposed prior to the onset of the rash. The other would be to obtain the water from the pool and, using a clean white towel or washcloth, soak a portion of the body in the pool water for this amount of time.

A negative test would indicate (but would not guarantee) that it would be safe for her to return to the pool. The opposite of course would be true for a positive test. Obviously, if the rash did not clear after cessation to exposure, one would think it would be very unlikely that it was due to exposure to the chlorinated pool water in the first place.

Thank you again for your inquiry and we hope this response is helpful to you.

International Journal of Environmental Health Research Volume 11, Issue 1, 2001 This study investigated adverse skin and eye effects in swimmers using pools with three different disinfection systems (chlorine, chlorine/ozone and bromine/ozone) and monitored water quality parameters that may be related to adverse health effects. A cross-sectional study of 770 children swimming in three school pools was carried out over a 4 week period in November 1994 using a postal questionnaire. Physico-chemical and bacteriological parameters of water quality were monitored on a weekly basis. Responses were obtained for 385 swimmers. Skin rashes with an onset less than 24 h after swimming in the school pool were reported by 4©\8% of swimmers. Compared with the bromine/ozone pool, the odds ratio (OR) of having a rash that started less than 24 h after pool use was 1.91 (CI 0.71©\5.10) for the chlorine pool and 1.88 (CI 0.61©\5.81) for the chlorine/ozone pool. Adjustment for possible confounders made no significant differences to these results. Eye redness, itch or irritation was reported by 23©\33% of swimmers and 24% of non-swimmers, and wearing swimming goggles had a protective effect (OR 0.40; CI 0.24, 0.65). Disinfectant levels were more consistently maintained in the pools with automatically controlled systems. The bromine disinfection system was not associated with a greater risk of the development of skin rashes than other disinfection systems, but the numbers were small, and need to be interpreted with caution.

Contact Dermatitis. 2012 Jun;66(6):335-9. doi: 10.1111/j.1600-0536.2012.02030.x.
Swimming pool contact dermatitis caused by 1-bromo-3-chloro-5,5-dimethyl hydantoin.
Dalmau G, Mart¨ªnez-Escala ME, G¨¢zquez V, Pujol-Montcus¨ª JA, Canadell L, Espona Quer M, Pujol RM, Vilaplana J, Gaig P, Gim¨¦nez-Arnau A.
Department of Allergy, Dermatology and Pharmacy, Hospital Universitari de Tarragona Joan XXIII, IISPV, Universitat Rovira i Virgili, Spain.
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.

Contact Dermatitis. 1999 Dec;41(6):347-8.
Allergic contact dermatitis from chlorinated swimming pool water.
Sasseville D, Geoffrion G, Lowry RN.

Phil Lieberman, M.D.

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