Angioedema is self-limited, localized swelling of the skin or mucosal tissues, which results from extravasation of fluid into the interstitium due to a loss of vascular integrity. Angioedema may occur in isolation, accompanied by urticaria, or as a component of anaphylaxis.
The pathogenesis and causes of angioedema will be reviewed here. The clinical features, diagnosis, differential diagnosis, and management of acute angioedema are discussed separately. (See "An overview of angioedema: Clinical features, diagnosis, and management".)
Data regarding the epidemiology of angioedema is limited. Most studies have evaluated adult populations. In a retrospective review of all hospital admissions in New York State over 13 years, angioedema was the second most common "allergic" disease to necessitate hospitalization, exceeded only by asthma . The number of angioedema hospitalizations per year more than doubled during the study period, suggesting that the prevalence may be increasing. African Americans were disproportionately affected, as they accounted for 42 percent of the admissions for angioedema, but only 16 percent of the state's population.
The epidemiology of specific forms of angioedema, such as hereditary angioedema due to C1 inhibitor deficiency, is discussed elsewhere. (See "Hereditary angioedema: Epidemiology, clinical manifestations, exacerbating factors, and prognosis".)
Angioedema results from a loss of vascular integrity that allows fluid to move into tissues. Exposure of the vasculature to inflammatory mediators causes dilation and increased permeability of capillaries and venules.