Aquagenic urticaria [Orticaria acquagenica]

Aquagenic urticaria (AU) is a form of inducible urticaria characterized by whealing at the site of skin contact with water, regardless of its temperature, within minutes of exposure. Approximately sixty cases, quite heterogeneous with regard to their severity and source of elicitation, have been reported in the literature. The clinical manifestations may be triggered by different types of water in different patients. There are forms that develop after exposure to salty water, forms that develop after contact with tap water, and even forms that are triggered by sweat, tears or a damp environment. A special form of OA has recently been identified, salt-dependent aquagenic urticaria (SDAU). This is characterized by being induced exclusively or predominantly by salty water, to occur in women of child bearing age and to involve the lower facial contours. The pathogenesis of AU is obscure. The disease is considered rare but it is probably underestimated, as mild cases do not come to the attention of dermatologists or may be misinterpreted as simple irritant reactions.