[Urticaria. Classification and diagnosis].

Urticaria belongs to the most frequent dermatologic diseases. Although the pathogenesis of urticaria is not fully understood, systematic studies in recent years have identified the most important triggering factors of the different forms of urticaria. Based on these results, it is recommended to restrict diagnostic procedures in acute urticaria to history and physical examination, while in chronic urticaria, one should exclude drugs, infections, pseudoallergic reactions, and autoimmune processes as causes. For the diagnosis of physical urticaria, standardized provocation test are recommended.