Frequently Asked Questions

“I encourage others to take the first step in owning and being proactive about HAE.”

Alex — Diagnosed with HAE in 2014

Discover answers

Frequently asked hereditary angioedema questions

 A: HAE is a rare genetic disorder. It can cause attacks of painful, disabling swelling anywhere in the body, but characteristic locations include the face, hands, feet, genitals, abdomen and throat.

Most people with hereditary angiodemia (HAE) don't have enough of a protein called C1 esterase inhibitor (C1-INH), or the protein their bodies produce does not work the way it should, which contributes to a cascade of events in the body. This cascade causes another protein called plasma kallikrein to trigger the release of a third protein called bradykinin. Having too much bradykinin causes the blood vessels to release fluid, resulting in localized swelling.

It's important to remember that an HAE attack that affects the throat is potentially life-threatening, because it puts you at risk of suffocation. Make sure you have a plan in place for this type of attack and seek emergency care as soon as possible.

Learn more about HAE »

 A: HAE is a rare genetic disorder. In fact, it's thought that only 1 in 10,000 to 1 in 50,000 people in the entire world have HAE.

Connect with others »

 A: Yes. Because HAE is rare, getting an accurate diagnosis can be challenging. In fact, one survey of 313 patients showed that up to 65% of people with HAE have been misdiagnosed with another condition prior to receiving their HAE diagnosis.

Learn more about diagnosis »

 A: 75% of HAE cases are passed down through families. The other 25% develop HAE because of a spontaneous change in their genetic code, so family history can't always help with diagnosis.

Learn more »

 A: Because HAE is rare, few people know about it, including many doctors. If you think there is a chance you have HAE, fill out the Symptom Profiler and take it with you to your doctor. It can help you and your doctor determine whether you should have your blood tested for HAE.

Start my Symptom Profiler »

 A: Finding a doctor who has experience diagnosing and helping patients manage HAE can be challenging. The US Hereditary Angioedema Association (HAEA) provides an online tool that can help you find a doctor who treats HAE.

Find a doctor »

 A: HAE is a genetic disorder that can be passed on from parent to child. If you have HAE, there is a 50% chance you will pass it on to your child.

See more about the genetics »

 A: HAE can cause attacks of painful, disabling swelling anywhere in the body, but characteristic locations include the face, hands, feet, genitals, abdomen and throat.

Usually, swelling in the skin occurs without hives or itchiness. An attack in the abdomen can cause mild to severe pain and be accompanied by vomiting and/or diarrhea.

Swelling in the throat, or a laryngeal attack, happens less frequently than skin or abdominal attacks but is the most serious. Swelling in the throat can become life threatening, because it can lead to suffocation. If you have a throat attack, you should seek emergency care right away.

HAE symptoms vary greatly from person to person. That means one HAE patient's symptoms could be very different from someone else who has HAE. HAE symptoms can also change within the same person. For instance, the frequency of attacks might increase as a patient enters adolescence.

Find out more about HAE symptoms »

 A: Although triggers can be different for everyone with HAE, some common triggers include:

  • Emotional stress
  • Minor trauma, surgery or dental procedure
  • Infection
  • Hormonal influences, like menstruation or using a contraceptive-containing estrogen
  • Mechanical pressure from physical activities, like mowing the lawn or using scissors

HAE attacks can also happen without warning or an obvious trigger. That can make it difficult to predict when an attack is coming, so it’s always important to have a plan in place in case of an emergency.

Find out more about triggers »

 A: Before an attack, some patients experience early warning signs, also called prodromes, such as tingling, rash, fatigue, or nausea. Please keep in mind that an HAE attack can also happen without warning, so you should always be prepared in case of an emergency.

Learn more about symptoms »

 A: HAE affects both men and women, but their experiences may be very different. For instance, women seem to be affected more severely by HAE than men. Fluctuations in the female sex hormones (including estrogen) can have an influence on HAE symptoms. As a result many women experience changes in the severity and frequency of their HAE attacks during various life stages such as childhood, puberty, pregnancies and menopause.

Learn more about women and HAE »

 A: Although there is currently no cure for HAE, there are treatment options available that can help prevent or reduce the frequency and severity of HAE attacks.

Prophylactic therapy involves taking medication for HAE attacks on a regular basis. The goal of this therapy is to reduce the likelihood of an attack occurring and decrease the severity and number of attacks.

Learn more about a prophylactic treatment »

On-demand therapy is treatment you take when you are having an HAE attack to treat the symptoms. HAE treatment experts recommend that all HAE patients have access to on-demand therapy.

Learn more about an on-demand treatment »

 A: When you live with a rare disease, it can be difficult to meet other people who know what you're going through from firsthand experience. Fortunately, there are several ways you can get involved in the HAE community. Here are just a few:

Explore HAE events »

Connect with us on Facebook »

Join the HAEA community »

 A: There are several organizations and advocacy groups that offer a range of resources for people living with rare diseases, including HAE. Discover tools you can start using now at and checking out the US Hereditary Angioedema Association (HAEA) at

The HAEA is a nonprofit patient advocacy organization dedicated to serving people with angioedema. They provide patients and their families with a support network and a wide range of services. The HAEA's mission is to:

  • Increase HAE awareness and education
  • Help people obtain an accurate HAE diagnosis
  • Facilitate patient access to therapy
  • Foster groundbreaking research that includes finding a cure

Go to the HAEA »