Acute urticaria and angioedema: diagnostic and treatment considerations

Urticaria is defined as wheals consisting of three features: (i) central swelling of various sizes, with or without surrounding erythema; (ii) pruritus or occasional burning sensations; and (iii) the skin returning to normal appearance, usually within 1-24 hours. Angioedema is defined as: (i) abrupt swelling of the lower dermis and subcutis; (ii) occasional pain instead of pruritus; (iii) commonly involving the mucous membranes; and (iv) skin returning to normal appearance, usually within 72 hours. Acute urticaria and angioedema is defined by its duration (<6 weeks) compared with chronic urticaria and angioedema. The most common causes are infections, medications, and foods. The best tools in the evaluation of these patients are a comprehensive history and physical examination. There are a variety of skin conditions that may mimic acute urticaria and angioedema and the various reaction patterns associated with different drugs. Oral antihistamines are first-line treatment. In the event of a life-threatening reaction involving urticaria with angioedema, epinephrine may be needed to stabilize the patient. This review focuses on the value of a comprehensive clinical evaluation at the onset of symptoms. It underscores the importance of coordination of care among physicians, and the development of an action plan for evidence-based investigations, diagnosis, and therapy.