Angioedema is characterized by localized swelling of sudden onset affecting the skin and/or mucous membranes. It can be classified into hereditary and acquired forms. Hereditary angioedema is a rare disease inherited as an autosomal dominant trait and caused by a deficiency of Cl-esterase inhibitor. Acute attacks are life threatening and cannot be managed by antihistamines, corticosteroids, or adrenergic drugs. Prophylactic therapy is possible with danazol or stanozolol. Acquired angioedema includes nonhereditary Cl-esterase inhibitor deficiency; idiopathic, allergic, and drug-induced forms; angioedema associated with lupus erythematosus and hypereosinophilia; and angioedema caused by physical stimuli. Treatment of these forms of angioedema depends on identifying and avoiding the cause, induction of tolerance, or symptomatic treatment with systemic antihistamines.