Hereditary angioedema (HAE) is a relatively rare, but potentially life-threatening genetic disorder characterized by marked, diffuse mucosal edema that, in extreme cases, can affect the airway leading to asphyxiation. The clinical picture is similar to that of other forms of angioedema; therefore, misdiagnosis or delayed diagnosis is common. HAE is caused by a deficiency in, or a dysfunction of, C1 esterase inhibitor, which has a wide variety of physiologic functions, of which regulation of the contact (kallikrein-kinin) system is most relevant to this condition. Effective management of HAE must consider routine/long-term prophylaxis, short-term prophylaxis (in advance of predicted trauma, eg, surgical or dental procedures), and treatment of acute attacks. Historically, treatment options have been limited to controlling symptoms, but progress in understanding the pathophysiology of HAE has facilitated development of treatments, such as C1 inhibitor therapy, or drugs targeted at the bradykinin pathway, which address the underlying pathologic process.