Urticarial reactions: vascular erythema, urticaria, vasculitis.

Vascular erythemas, including urticaria and vasculitis, represent diagnostic and therapeutic challenges. A careful systemic approach to history and physical examination should be followed by appropriate investigations to rule out systemic disease. Chronic urticaria patients should be physically tested to identify cholinergic, dermagraphic, and cold-induced responses. Food diaries and careful drug history may be important to identify exacerbating factors in chronic urticaria.A skin biopsy is necessary to diagnose vasculitis. Therapy of any underlying cause is supplemented with H1 antihistamines in urticaria patients, while vasculitis requires a different anti-inflammatory approach.