Urticarial vasculitis.

Urticarial vasculitis describes a distinct entity in which the gross cutaneous lesions resemble urticaria and histologically show features of a vasculitis. The incidence of vasculitis in patients with apparent urticaria is between 2% and 20%. The diagnosis is suggested clinically by more persistent (lasting > 24 hours) and more symptomatic weals than in ordinary urticaria and by the presence of residual bruising. In addition to the skin the musculoskeletal, respiratory, renal and gastrointestinal systems may be involved in the disease, which is probably an immune complex mediated process. Urticarial vasculitis is most commonly an acquired idiopathic phenomenon but may occur in association with other disorders most often systemic lupus erythematosus, Sjögren's syndrome and serum sickness. In this article we review the background, histopathology, clinical features, extracutaneous manifestations, pathogenesis, aetiology, associated diseases, investigation, treatment, course and prognosis of urticarial vasculitis.