Urticaria and angioedema.

Urticaria, also known as hives, may affect up to 20% of the population at some time. Urticaria is described as pruritic erythematous, raised, circumscribed lesions with central pallor that blanch with pressure. Urticaria is closely associated with angioedema in 40% of individuals; approximately 10% of patients experience angioedema without urticaria. Urticarial lesions often are generalized, with multiple lesions in no specific distribution; angioedema tends to be localized and commonly affects the face (periorbital and perioral regions) or tongue. Urticaria is subdivided into acute and chronic urticaria based on the duration of symptoms. Acute urticaria lasts < 6 weeks, and an identifiable cause, such as food products, medications (aspirin, nonsteroidal anti-inflammatory drugs, antibiotics), or insect stings, may be discovered. Urticaria that lasts for >6 weeks is designated as chronic urticaria, and an etiology is seldom identified and thus considered spontaneous. Chronic urticaria may have an autoimmune basis. There is a well-documented association between autoimmune hypothyroidism (Hashimoto disease) and urticaria and angioedema, with a higher incidence of antithyroid (antithyroglobulin and antiperoxidase) antibodies in these patients, who are usually euthyroid. Furthermore, results of studies revealed a circulating immunoglobulin G (IgG) antibody directed against the high affinity IgE receptor alpha subunit IgE receptor (FcεRI) or IgE in 40-60% of patients with chronic urticaria. A stepwise approach to the treatment of urticarial is recommended with second-generation H1 antihistamines being the first line of therapy.