Hereditary angioedema - A broad review for clinicians

Hereditary angioedema (HAE) is an autosomal dominant disease that afflicts 1 in 10000 to 1 in 150000 persons; HAE has been reported in all races, and no sex predominance has been found. It manifests as recurrent attacks of in tense, massive, localized edema without concomitant pruritus, often resulti ng from one of several known triggers. However, attacks can occur in the ab sence of any identifiable initiating event. Historically, 2 types of HAE ha ve been described. However, a variant, possibly X-linked, inherited angioed ema has recently been described, and tentatively it has been named "type 3" HAE. Signs and symptoms are identical in all types of HAE. Skin and viscer al organs may be involved by the typically massive local edema. The most co mmonly involved viscera are the respiratory and gastrointestinal systems. I nvolvement of the upper airways can result in severe life-threatening sympt oms, including the risk of asphyxiation, unless appropriate interventions a re taken. Quantitative and functional analyses of Cl esterase inhibitor and complement components C4 and Clq should be performed when HAE is suspected . Acute exacerbations of the disease should be treated with intravenous pur ified Cl esterase inhibitor concentrate, where available. Intravenous admin istration of fresh frozen plasma is also useful in acute HAE; however, it o ccasionally exacerbates symptoms. Corticosteroids, antihistamines, and epin ephrine can be useful adjuncts but typically are not efficacious in abortin g acute attacks. Prophylactic management involves long-term use of attenuat ed androgens or antifibrinolytic agents. Clinicians should keep this disord er in their differential diagnosis of unexplained, episodic cutaneous angio edema or abdominal pain.