Acute urticaria.

Acute urticaria is a common condition, which presents in all age groups and to multiple specialties. It may be a presenting symptom of anaphylaxis. The following article describes the epidemiology, etiology, clinical features, differential diagnosis, investigations, management, and prognosis of acute urticaria. Contact urticaria and angioedema without urticarial weals are not covered, as these are described elsewhere in this issue.