Diagnosis and management of hereditary angioedema.

Hereditary angioedema (HAE) is characterized by sudden attacks of deep tissue swelling caused by C1 inhibitor deficiency. Swelling severity can vary from mild to severe, and some patients are at risk for disability and death from either asphyxiation or hypovolemic shock. Many HAE attacks are precipitated by trauma or stress. The extremities, genitalia, trunk, bowels, face, and larynx are commonly affected areas, but swelling can affect any single part of the body or multiple sites. Symptoms typically worsen over 24 to 36 hours and resolve within 48 hours. Because many symptoms of HAE overlap with those of other medical conditions, diagnosis may be delayed. A thorough family history can identify the signature symptoms of HAE, which include a family history of HAE, recurrent edema without urticaria, and symptomatic worsening during puberty. The author presents two hypothetical cases of HAE and reviews the clinical hallmarks of this condition, diagnostic tests, and available treatments.