Angioedema is the swelling of the deeper layers of the skin, caused by a build-up of fluid.

The symptoms of angioedema can affect any part of the body, but swelling usually affects the:

  • eyes
  • lips
  • genitals
  • hands
  • feet

Many people with angioedema also experience urticaria (hives). This is a raised, red and itchy rash that appears on the skin.

Read more about the symptoms of angioedema.

Why does angioedema happen?

The cause of angioedema depends on the type you have. There are four main types of angioedema:

  • allergic angioedema – the swelling is caused by an allergic reaction, such as a reaction to peanuts, and sometimes occurs in combination with anaphylaxis
  • idiopathic angioedema – there is no known cause for the swelling (although certain factors, such as stress or infection, may trigger the symptoms)
  • drug-induced angioedema – the swelling is a side effect of certain medications, most often angiotensin-converting enzyme (ACE) inhibitors
  • hereditary angioedema – the swelling is caused by "faulty" genes that are inherited from a person’s parents

Read more about the causes of angioedema.

Who is affected

Angioedema is a common condition, affecting about 10-20% of people during their life, although some types are more common than others.

Hereditary angioedema is rare, only affecting between 1 in 10,000 and 1 in 50,000 people worldwide.


Your doctor can diagnose angioedema by examining the affected skin and discussing symptoms.

However, further tests, such as blood tests or allergy tests, may be required to determine the type of angioedema.

Idiopathic angioedema is only diagnosed if no cause can be found.

Read more about diagnosing angioedema.

How is angioedema treated?

Although most cases of angioedema get better without treatment after a few days, medication is often used.

For cases of allergic and idiopathic angioedema, antihistamines and oral steroids (steroid tablets) can be used to relieve the swelling.

Drug-induced angioedema can usually be treated by using an alternative medication to treat whatever underlying condition you have.

Although the condition cannot be cured, regular drug treatment can prevent attacks in people with hereditary angioedema.

Read more about treating angioedema.


Angioedema can sometimes occur in combination with anaphylaxis – a severe, potentially life-threatening, allergic reaction.

Signs of anaphylaxis include:

  • narrowing of the airways, which can cause wheezing and breathing difficulties
  • feeling dizzy or fainting

Anaphylaxis should always be treated as a medical emergency. Dial 999 for an ambulance.

Read more about anaphylaxis.

Last updated: 28 August 2015

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