Urticaria and Angioedema

Abstract

Patients exhibiting hives and associated soft tissue swelling are common in the outpatient setting. These complaints brought to the primary care physician generally will result in a diagnosis of urticaria and angioedema. The patients refer to the urticaria and angioedema by various descriptive terms, such as hives, welts or an itchy rash. Indeed, the lesions that are described by patients with a variety of terms can have a diverse appearance. Categorically, urticarial lesions are pruritic and have a center portion that is elevated. The elevated center is often surrounded by an erythematous halo. This prototypical lesion morphologically has a central wheal with a surrounding flare. However, the configuration of the lesions can be quite different, with some lesions typically being round and circumscribed, while others can be serpiginous or diffuse. Characteristically, the lesions should blanch with pressure, and they generally resolve within 24 h, leaving no residual change to the skin. Lesions that do not blanch, result in pigmentation or scarring of the skin, or are not pruritic should be assessed for other dermatological processes or vasculitis.