Hereditary angioedema

Key points about hereditary angioedema (HAE)

  • Angioedema refers to swelling of the deeper layers of your skin and tissue, and hereditary means a genetic condition passed down from your parents.
  • HAE is caused by a problem with the gene controlling a blood protein called C1 Inhibitor. This raises the level of a chemical called bradykinin, which causes swelling.
  • Your hands, feet, face, throat, airway, genitals and gut can swell. Airway swelling is particularly dangerous, if you or someone else has airway swelling, call 111. 
  • HAE can't be cured, but medication can help prevent and treat the swelling.
  • This condition affects your day to day life, so it’s important to get support for living with it.
Three generations of smiling women in kitchen

  • Between one in every 50,000 to one in 150,000 people have HAE.
  • Most people experience their first episode of HAE when they are a child or teenager.
  • Because HEA is rare, it can take a while before it is diagnosed.

Episodes can happen for no clear reason, but they may be caused by:

  • stress and anxiety
  • injuries or infections
  • minor operations and dental surgery
  • illnesses such as colds or flu
  • being pregnant or having your period
  • high blood pressure medication, known as ACE inhibitors.

The key symptom is swelling in your hands, feet, face, throat, airways, digestive tract or genitals. The swelling is not itchy, and treatments for swelling caused by allergies do not help HAE-related swelling.

If the swelling is in your gut, you will have pain, nausea and vomiting. If the swelling is in your airway, it will affect your breathing and you need to call 111.

How often these symptoms happen and how long they last varies from person to person, but they may happen once or more a month and last for two to three days.

Your doctor will do a physical examination and refer you for blood tests to see if the swelling is caused by an allergy or the C1 esterase deficiency that causes HAE. If you do have HAE, they will refer you to a specialist.

The treatment of angioedema depends on the severity of the episode. In most cases of mild HAE, such as mild facial swelling, the symptoms go away by themselves after a few hours or days, and they may not need treatment. 

Severe cases will require emergency treatment with a blood product called  c1 inhibitor concentrate. This is given directly into the vein. A medicine called icatibant (Firazyr®)  can also be used in emergencies for acute attacks of hereditary angioedema, but only in people with C1-esterase-inhibitor deficiency. This medication can be administered by injection by the patient or carer in an emergency, but to qualify for funding, you must meet special criteria and receive training on how to administer the injection.

If you suffer from frequent attacks, to reduce your chance of an acute attack your doctor may prescribe as a preventative either anabolic steroids (such as danazol or stanazolol) or regular c1 inhibitor concentrate. 

Benedikte Hellevik tells her personal story about life with HAE.

(HAE International, 2015)

  • Always take your medication to prevent episodes, and if an episode happens, take your medication for that.
  • Follow your action plan.
  • During a mild attack, try a cool shower or a cold cloth on the swelling.
  • Get support for living with HAE.

(HAE Australasia, Australia, 2021)

(HAE Australasia, Australia, 2021)

The following links provide further information about hereditary angioedema. Be aware that websites from other countries may have information that differs from New Zealand recommendations.   

HAE Australasia(external link) 
Genetics Home Reference(external link) National Library of Medicine, US, 2017
Genetic and Rare Diseases Information Center(external link) US, 2011 
Angioedema(external link) DermNet NZ
Managing your child's HAE at school(external link) HAE Australasia, 2017
Medic Alert(external link) NZ
Rare Disease Day(external link) International

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