Hereditary Angioedema (HAE)

This article first appeared in the fall 2014 issue of Allergy & Asthma Today. It was written by Janet Long, executive vice president at the US Hereditary Angioedema Association (HAEA).

I was diagnosed with Hereditary Angioedema (HAE) when I was 40 years old. For years, doctors thought my hand swelling was due to contact allergies even though the swelling had no consistent pattern.

Then, in 1999, symptoms that included episodes of swelling accompanied by abdominal pain and vomiting became unbearable, and an allergist ordered a simple blood test that confirmed the diagnosis.

My story is not unusual: it took me decades to be accurately diagnosed. For so long, the disease was poorly understood and treatment options were few. With so few HAE specialists available, I had years of swelling attacks with little relief. If not for the diagnosis, severe throat swelling could have ended my life.

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

An estimated 6-10,000 people in the United States have HAE, but because the disease is so rare, it is not uncommon for patients to remain undiagnosed for years.

Allergists often treat HAE because the swelling episodes resemble allergic reactions. However, HAE cannot be treated by standard allergy medications, including corticosteroids, antihistamines and epinephrine.

What causes HAE swelling?

HAE does not affect everyone the same way, even within the same family. Most episodes occur for no apparent reason; however stress, traumas, anxiety, illnesses such as the cold and flu, and surgery (particularly dental surgery) are common triggers.

For women, hormonal changes during menstruation and pregnancy seem to have an effect, sometimes worsening symptoms and sometimes easing them.

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 their throat starts to swell or their breathing is compromised.

How is HAE diagnosed?

HAE is diagnosed with a simple blood test that measures levels of C1 inhibitor and C4 protein levels in the blood.

Because HAE is so rare, and requires an individualized treatment plan, seeing an HAE medical specialist is especially important. If you’re diagnosed with HAE, ask your primary care doctor or allergist for a referral.

Questions to ask on a first visit:

1) How do I determine what my attack triggers are?

2) How soon should I treat my HAE attack?

3) Who do I call for an HAE emergency outside of normal office hours?

4) What are the chances my children will inherit HAE?

The US Hereditary Angioedema Association (HAEA) has established a new international reference center for angioedema at the University of California, San Diego. In addition to treating patients, HAE physicians conduct clinical trials at the center.

What treatment options are available for HAE?

FDA has approved four medications for HAE patients from which to create their individualized treatment plan: Berinert®, Kalbitor® and Firazyr®, which treat attacks once they have begun, and Cinryze™, which helps prevent attacks.

Berinert and Cinryze are both delivered intravenously while Kalbitor and Firazyr are delivered by subcutaneous injection. Some can be self-administered at home. Patients should talk with an HAE specialist about which medication is best for them.

Older therapies such as attenuated androgens and fresh frozen plasma are no longer first-line treatments. More HAE therapies are undergoing clinical trials and could come to market in the near future.

Patient Support

The US Hereditary Angioedema Association (HAEA) is a nonprofit patient advocacy organization and support network founded and staffed by HAE patients and patient caregivers. The organization’s goal is to increase awareness of HAE, advance clinical research and ultimately find a cure.

HAEA offers a full Continuing Medical Education program for physicians and its 2013 Recommendations for the Management of HAE is available at www.haea.org.