Etiology, classification, and treatment of urticaria.

Urticaria is among the most common skin diseases. It can be acute, chronic, mediated by a physical stimulus, or related to contact with an urticant. Some cases result from an underlying small vessel vasculitis. Our understanding of this condition is continuously expanding, and autoimmune mechanisms are now recognized as a cause of chronic urticaria. A search of the PubMed database (US National Library of Medicine) for "urticaria" yields more than 12,000 results. Our goal is to discuss the current understanding of the etiology, classification, and treatment alternatives. As the topic is comprehensive, our discussion will be limited to a concise review.