Aquagenic Urticaria Diagnosed by the Water Provocation Test and the Results of Histopathologic Examination.

An 18-year-old male visited our department complaining of recurrent episodes of an itchy rash after hand washing, showering/bathing, drinking water, and getting rain-soaked. He was diagnosed with aquagenic urticaria after a water provocation test and histopathologic examination. Five months of antihistamine treatment successfully prevented further wheal formation. Aquagenic urticaria is a very unusual form of physical urticaria caused by contact with water. It manifests as pruritic small wheals surrounded by erythema within 30 minutes of exposure. The condition can be diagnosed by a water provocation test. Systemic antihistamines are the first-line treatment, with anticholinergics, phototherapy, or barrier cream used alternatively or additionally. Four cases of aquagenic urticaria have been reported in Korea, but no histopathologic evaluation was reported in the English or Korean literature. Herein, we provide both a case report of aquagenic urticaria diagnosed by the water provocation test and histopathologic examination results for this patient.