Hereditary angioedema is relatively rare and is often misdiagnosed as an allergic reaction to medication or food. What symptoms are helpful differentiating points for making an accurate hereditary angioedema diagnosis? Dr. William Lumry, clinical professor of internal medicine at the University of Texas Southwestern Medical School, outlines the types of hereditary angioedema, factors which can contribute to an acute attack, and therapies to prevent or treat patients with this condition. Dr. Ketan Sheth hosts.