A to Z: Hereditary Angioedema

May also be called: HAE

Hereditary angioedema (huh-RED-uh-tair-ee an-GEE-oh-uh-DEE-muh) is a rare genetic disorder of the immune system that causes episodes of swelling, particularly in the hands, feet, face, and airways.

More to Know

When someone has hereditary angioedema (HAE), it means they were born with a defect in the gene that controls a protein called C1 inhibitor that is found in the blood. Normally, C1 inhibitor works with the body’s immune system to regulate the chemicals that the body uses to fight diseases and respond to injuries. If C1 inhibitor is missing or defective, the chemicals can become imbalanced, leading to excess fluids being released into body tissue. This can cause a type of swelling known as edema.

The symptoms of HAE usually start in childhood and get worse during puberty. Without treatment, people with HAE can have attacks of swelling as often as every 1 to 2 weeks. Most episodes last for about 2 to 4 days. The symptoms depend on how severe the episode is and what part of the body is affected. Swelling in the intestinal tract can lead to severe abdominal pain, nausea, and vomiting. Swelling in the airways can lead to life-threatening obstruction of the airways. Some people also develop a non-itchy rash that is sometimes mistaken for hives.

Common causes, or triggers, of HAE episodes include dental work, hormonal changes, sicknesses like colds and the flu, surgery, stress, and certain medicines. Often, episodes happen for no apparent reason. Treatment for HAE depends on the symptoms and often involves medicines that help the body make more C1 inhibitor. If bacteria are causing the HAE episode, a doctor may prescribe an antibiotic as part of the treatment.

Keep in Mind

Swelling of the airways can be life-threatening, so anyone who develops symptoms of an HAE episode should see a doctor or get to a hospital emergency department right away. Fortunately, due to recent developments in medicines to treat HAE, most people with the condition have an excellent outlook as long as they follow a proper treatment plan.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.