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.

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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.

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.
Image dreamstime

Photo does not depict actual patient.

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

  –BERINERT patient

 Hae Attack Facial


Hae Attack Facial Normal

During cutaneous
attack: Nonpitting

Hae Attack Abdominal


Hae attack abdominal after

abdominal attack:
gastrointestinal pain,
nausea, vomiting,
swelling of abdomen

Hae Attack Laryngeal


Hae Attack Laryngeal After

During laryngeal
attack: voice
change, hoarseness,
swelling of larynx

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