A 49-year-old white man has a three-year history of perifollicular, punctate hives on well-circumscribed areas of the forearms, shoulders, and chest whenever these areas come in contact with water. The phenomenon first appeared after the patient had been sprayed in these areas with hydrochloric acid and potash in an industrial accident. It is consistently reproducible by the topical application of tap water, either by cloth or faucet drip, and is similar clinically to the three cases of aquagenic urticaria reported previously by Shelley and Rawnsley. The process is not related to water temperature, and psychogenic factors appear to have no influence. Our results support Shelley's hypothesis that aquagenic urticaria is probably due to a histamine-mediated mechanism.
Chalamidas SL, Charles CR. Aquagenic Urticaria. Arch Dermatol. 1971;104(5):541-546. doi:10.1001/archderm.1971.04000230083015