Water-induced dermatosis: Aquagenic keratoderma. A case report.

Aquagenic keratoderma is a benign entity that is characterized by producing whitish or translucent papules a few seconds after contact with water. We present the case of a 16-year-old patient with multiple asymptomatic confluent papules that appeared on both hand palms after contact with water and which disappeared after drying. The histopathological findings in a skin biopsy after water exposure showed changes in the superficial layers of the stratum corneum and dilatation of sweat gland ducts. This entity of unknown etiology has been related to neuronal and eccrine gland dysfunction. Recently it has been associated with alterations of aquaporins. The “hand-in-the-bucket” sign is a simple useful clinical tool for diagnosis, as histopathological findings may be nonspecific. Topical treatments include barrier mechanisms and botulinum toxin.