HAE – Hereditary Angioedema


What is HAE?

Hereditary angioedema (HAE) is a rare and potentially life-threatening genetic disease causing episodes of severe and painful swelling (called edema) in the hands, feet, arms, legs or face, as well as the gastrointestinal tract.

Who has HAE?

HAE affects about 1 in 10,000 to 1 in 50,000 people worldwide. It’s caused by a defect in the gene that controls a blood protein called a C1 inhibitor; the lack of C1 INH is called Type 1 and when C1 INH is present but does not function, it’s called Type II. Both produce swelling.

Allergists often treat HAE because the swelling appears to be an allergic reaction. However, HAE cannot be treated by standard allergy medications, including antihistamines, corticosteroids and epinephrine.

How is HAE diagnosed?

HAE is diagnosed with a simple blood test that measures levels of C1 inhibitor (usually low when HAE is present) and C4 proteins (usually low when HAE is present).

Who treats HAE?

Because HAE is so rare and requires a personalized treatment plan, seeing an HAE specialist is important. If you’re diagnosed with HAE, ask your doctor for a referral to an immunologist.

What triggers HAE?

Most HAE swelling occurs for no apparent reason. However, many patients report that stress, anxiety, illness such as a cold or the flu, and surgery (particularly dental surgery) are common symptom triggers. For women, hormonal changes during menstruation and pregnancy appear to have an effect, sometimes worsening symptoms and sometimes easing them.

HAE swelling episodes can last 2-5 days if left untreated. In the gastrointestinal tract, swelling can lead to severe abdominal pain, nausea and vomiting.

Swelling of the throat, or laryngeal edema, is particularly serious because it can close the airway and cause death by asphyxiation. HAE patients should seek treatment as soon as they recognize symptoms of throat swelling, including changes in voice or difficulty breathing.

How is HAE treated?

The U.S. Food and Drug Administration (FDA) has approved seven medications to help treat or prevent HAE swelling. Patients should talk with an HAE specialist about which therapy is best for them. Some treatments can be self-administered at home.

More therapies are undergoing clinical trials and could come to market in the near future.

Patient Resources

U.S. Hereditary Angioedema Association (HAEA) haea.org.

Patient Stories

Janet’s Story

For years, doctors thought my hand swelling was due to contact allergies even though there was no consistent pattern. When I was 40 years old, symptoms that included episodes of swelling accompanied by abdominal pain and vomiting became unbearable. An allergist ordered a blood test that confirmed it was hereditary angioedema.

My story is not unusual. It can take years for HAE to be accurately diagnosed. I had years of swelling with little relief. If not for the diagnosis, severe throat swelling could have ended my life.

Today, HAE specialists can help create an individualized treatment plan that makes it possible to lead a full life.

Janet F. Long
Director of HAE Research
U.S. Hereditary Angioedema Association