Angioedema is swelling underneath the skin. It's usually a reaction to a trigger, such as a medicine or something you're allergic to.
It is not normally serious, but it can be a recurring problem for some people and can very occasionally be life-threatening if it affects breathing.
Treatment can usually help keep the swelling under control.
The swelling most often affects the:
Many people also have a raised, itchy rash called urticaria (hives).
Read more about the symptoms of angioedema.
See your GP if you have episodes of swelling that affect your skin or lips and you're not certain of the cause.
You may need to have some tests to determine the cause. Read more about tests for angioedema.
Dial 999 for an ambulance if you, or someone with you, has swelling and:
These are signs of a serious allergic reaction (anaphylaxis). If you, or the person who's ill, have been prescribed an adrenaline auto-injector for this, use it while waiting for the ambulance to arrive.
There are several different types of angioedema, each of which has a different cause.
It can be caused by:
But in many cases, it's not clear what causes angioedema. This is known as idiopathic angioedema.
Read more about the causes of angioedema.
The swelling will usually get better by itself in a few days, but there are treatments that can help it settle faster and reduce the risk of it happening again.
The treatments recommended depend on the type of angioedema you have. For example:
Angioedema can usually be treated at home, although treatment in hospital may be necessary in serious cases.
Read more about how angioedema is treated.