Angioedema is swelling underneath the skin. It’s usually a reaction to a trigger, such as a medication or something you’re allergic to.

It isn’t normally serious, but it can be a recurring problem for some people and can very occasionally be life-threatening if it affects breathing.

There are several different types of angioedema, each of which has a different cause.

It can be caused by:

• An allergic reaction, such as a food allergy – this is known as “allergic angioedema”
• A medication, such as angiotensin-converting enzyme (ACE) inhibitors for high blood pressure – this is known as “drug-induced angioedema”
• A genetic fault that you inherit from your parents – this is a rare, lifelong condition that usually starts in childhood called “hereditary angioedema”

But in many cases, it’s not clear what causes angioedema. This is known as “idiopathic angioedema”.