What is hereditary angioedema (HAE)?

HAE is a rare inherited disease that can cause attacks of swelling, and often pain, in specific parts of the body, including the abdomen, face, and throat.


Facial attack image


Abdominal attack image

What happens during an HAE attack?

During an attack, abdominal, facial, and laryngeal swelling often gets worse over a period of 12 hours to a day, then gradually resolves over the following 2–5 days. Unlike allergic reactions, there is no itching or redness with HAE. In addition to abdominal swelling and pain, people often experience nausea, which can be accompanied by vomiting.

Attacks of HAE in the throat are the most dangerous because swelling that closes off the airway may be life threatening. Abdominal attacks cause acute pain in the abdomen, and sometimes also cause nausea, vomiting, and diarrhea.

What causes HAE attacks?

HAE attacks are caused by low levels of functioning C1-esterase inhibitor (C1-INH), a key protein in the body that controls swelling and inflammation. People with HAE have a genetic disorder that results in either too little (type I) or nonfunctioning (type II) C1-INH, making them susceptible to sudden and unpredictable attacks of swelling. In very rare cases, a person can experience HAE attacks even though C1-INH levels and functionality appear normal.

BERINERT treats two common types of HAE:

Types of HAE

Living with HAE

HAE attacks typically begin in childhood, becoming more severe over time. The number of episodes an individual may experience is unpredictable. Some people have weekly attacks, while others may go years without one.

  • HAE attacks can occur suddenly and without much warning.

    Worrying about your next attack can cause a great deal of stress for you and your family, but having a fast and reliable on-demand treatment plan can help put you back in control.
  • Recognizing the early signs of an HAE attack can help you treat early.

    Common warning signs that can signal the onset of an HAE attack include:
    • Sudden mood changes
    • Irritability or aggressiveness
    • Anxiety
    • Extreme fatigue
    • Rash or tingling sensation of the skin where the swelling begins
    • Nausea

Understanding what triggers your attack

Many people with HAE find that specific situations or activities can trigger an HAE attack. Recognizing those triggers can help you avoid them and/or be prepared to act fast if you think you’ve experienced a trigger. Below are some common triggers.

Fatigue or stress

Accidental trauma


Dental, medical, or surgical procedures

Fever, illness, or infection

Menstrual cycle or hormonal changes

Medications such as estrogen-containing oral contraceptives, hormone replacement therapy, or ACE inhibitors

Doctor Discussion Guide

Get the most out of your doctor visits

Taking a few moments to prepare for your visits to the doctor can help make them more productive.
Use this discussion guide to help remember and communicate important details that can help you and your doctor have a more thorough conversation.

"The first symptoms I feel are usually sharp abdominal pains."

–BERINERT patient
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