Diagnosis

If you haveexperienced 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 below.

Symptoms and medical history

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

For example:

• it's likely to have been caused by an Indoor allergy if youwere 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 amedication 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 inheritedgenetic 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 mayrefer 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
• a 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.This substance is important in regulating the immune system.

A very low level ofC1 esterase inhibitor would suggestyou have an inherited problem affecting how much ofthis substanceyour bodyis able toproduce.