Angioedema : Diagnosis

If you have experienced angioedema for the first time, your doctor will try to work out what may have caused it.

There are several different causes of angioedema. It's important to know what's causing your symptoms, as this affects the treatment you'll need.

There's no single test to determine the cause of angioedema. Some of the checks and tests you may have are outlined in this section.

Symptoms and medical history

Your doctor may be able to get a good idea of the cause of your angioedema by asking about your symptoms and medical history.

For example:

  • it's likely to have been caused by an allergy if you were exposed to something that can trigger allergic reactions (an allergen) soon before it started, or if you also developed a raised, itchy rash (urticaria or hives)
  • it may have been triggered by a medicine if you're currently taking a medicine that's associated with angioedema, such as angiotensin-converting enzyme (ACE) inhibitors for high blood pressure
  • it's possible your symptoms are a result of an inherited genetic fault if you have a family history of angioedema

Sometimes the tests below may be needed to confirm the cause.

Allergy tests

If your doctor thinks your symptoms may have been caused by an allergy, they may refer you to a specialist allergy or immunology clinic for further testing.

Tests you may have include:

  • a skin prick test – your skin is pricked with a tiny amount of the suspected allergen to see whether there's a reaction
  • blood test – a sample of your blood is tested to determine whether your immune system reacts to a suspected allergen

These tests can help determine what you're allergic to. Read more about allergy testing.

Blood test

If your doctor thinks your symptoms may be caused by a genetic fault you've inherited from your parents, they may refer you for a blood test.

The test checks the level of a substance called C1 esterase inhibitor in your blood. This substance is important in regulating the immune system.

A very low level of C1 esterase inhibitor would suggest you have an inherited problem affecting how much of this substance your body is able to produce.