What is HAE?

Begin here to learn about this rare disease that causes swelling throughout the body


If you’re trying to get a grasp on what this rare disease is, you’ve come to the right place. Let’s start by covering some of the basics.

Hereditary angioedema, or HAE, is a rare disease of the immune system that causes spontaneous swelling throughout the body. In fact, it’s so rare that it only affects an estimated 1 in 50,000 people around the world.

The “angioedema” in HAE refers to a swelling of the skin that is similar to hives. But unlike hives, the swelling in HAE is sometimes below the skin’s surface and is not itchy. Often times, the swelling can be rather painful and severe.

If you have HAE, you may have started experiencing symptoms around puberty, but the swelling can sometimes start in childhood. On average, untreated HAE patients have sudden attacks (or symptom flare-ups) every 7-14 days, each generally lasting 2-5 days before resolving on their own. Most patients will continue to have HAE attacks throughout their lives, but some may find that their symptoms occur less often as they get older.

Attacks usually affect three areas of the body

HAE attacks are unpredictable and can happen anywhere on the body, but they tend to affect three main places on the body: 

  • Peripheral areas  (face, genitals, hands, and feet): Attacks in these areas can be uncomfortable and disfiguring.
  • Abdomen (stomach): Attacks in the abdomen are extremely painful and often lead to nausea and vomiting. Abdominal attacks are very common, having been reported in more than 93% of patients.
  • Larynx (throat): This is the least common, but most dangerous type of attack because it can block a person's breathing. About 50% of all HAE patients experience a laryngeal attack at least once in their lifetime, and some patients have had them several times. Because these attacks can get worse quickly, you should always seek medical treatment right away if you feel a throat attack coming on.


HAE can be a family affair

HAE is "hereditary" because it is caused by a genetic defect that is passed through families. When a parent has HAE, there is a 50% chance that his or her child will inherit the disease.

A typical patient with HAE often has several family members with the condition. However, in 25% of HAE patients, HAE is not inherited, but caused by a random mutation of the C1 esterase inhibitor (CI-INH) gene. In other words, you can have still have HAE even if no one in your family has the disease. Keep in mind, though, that once the mutation occurs, it has the potential to be passed on to your children.

What does an HAE attack look like?

Most HAE attacks involve uncomfortable swelling of the face, hands, feet, or genitals.
See attack photos

Think you might have HAE?

A diagnostic test can help you find out if you or a family member might have HAE.
Get tested