ABSTRACT Aquagenic urticaria (AQ) is a rare physical urticaria induced by contact
with water. It may be distinctive clinically, evident as 0-0 mm folliculopapular urticaria, a pattern also characteristic of cholinergic urticaria. AQ has a truncal and upper extremity distribution within 00-00 minutes after contact with water, regardless
of its temperature or source. AQ is usually symptomatic with mild to severe pruritus
and a burning sensation. The mechanism by which water produces mast cell degranulation and histamine release remains unclear. We review its clinical presentation, diagnostic parameters, differential diagnosis, and treatment.