Angioödeme

Angioödeme, or angioedema, is the rapid swelling of the deeper layers of the skin and mucous membranes. It often affects the face, lips, tongue, throat, extremities, and genitals. The swelling is typically non-pitting and can last from several hours to a few days. Angioedeme may occur with urticaria or alone, and its underlying mechanism may be histamine-mediated or bradykinin-mediated, which influences treatment and prognosis.

Angioedeme is classified by mechanism and cause. Histamine-mediated angioedema is often linked to allergic reactions or occurs idiopathically and usually responds to antihistamines, corticosteroids, and, when appropriate, epinephrine. Bradykinin-mediated angioedema does not usually involve itching or hives and can be more persistent. Hereditary angioedema (HAE) is a genetic disorder typically due to deficiency or dysfunction of C1 esterase inhibitor (C1-INH) and follows an autosomal dominant pattern; it often begins in adolescence. Acquired angioedema (AAE) occurs later in life, frequently in association with autoimmune disorders or lymphoproliferative diseases. ACE inhibitor–induced angioedema is another bradykinin-mediated form and can occur at any time after starting the medication.

Diagnosis relies on clinical history and presentation, with laboratory tests guiding suspected hereditary disease. In suspected HAE, C4 levels are often reduced between attacks, and C1-INH antigenic level and functional activity are assessed; genetic testing for SERPING1 mutations may be used. Distinction from allergic angioedema is based on the absence of urticaria and a limited or poor response to antihistamines.

Management focuses on the underlying mechanism. For histamine-mediated attacks, antihistamines, corticosteroids, and supportive care are typical. Bradykinin-mediated attacks require targeted therapies such as C1-INH concentrates, bradykinin receptor antagonists (e.g., icatibant), or kallikrein inhibitors, and airway management for laryngeal involvement. Long-term prophylaxis for hereditary angioedema includes C1-INH replacement or other agents, with avoidance of triggers and discontinuation of ACE inhibitors if implicated.