Causes of HAE

What causes HAE attacks?

While scientists don't know everything about the events that lead to an attack, studies show that most people with hereditary angioedema (HAE) either do not have enough protein in their blood, or it doesn't work the way it should.


C1-INH deficiency, or C1-INH, does not work properly


Increased activity of protein called plasma


Excess bradykinin is produced


Swells of an HAE attack occur

Normally, C1 esterase inhibitor (C1-INH) helps to regulate plasma kallikrein. When there is not enough functioning C1 esterase inhibitor (C1-INH), the activity of plasma kallikrein increases. Too much plasma kallikrein activity triggers the release of bradykinin. Increased bradykinin levels cause blood vessels to release fluid and result in the localized swelling and pain of an HAE attack.

Find the things that inspire you to fight this terrible disease. Keep those pieces of hope and joy close to you. They'll motivate you to find the right doctor, the right treatments, and the right people you need to be successful.

Kevin, Living with HAE

Kevin, patient living with HAE.

Is there a genetic test for hereditary angioedema (HAE)?

To know for certain that you have HAE, a blood test is recommended. Your doctor will measure your levels of the proteins C4 and C1 esterase inhibitor. If you have HAE, this test can also help determine whether you have Type I or Type II HAE. In some instances, you may need to take a genetic test.

Because HAE is rare, few people know about it, including many doctors. If you think there is a chance you have HAE, check out the HAE Disease Education Brochure. Then talk to your doctor about it so he or she can decide if you should be tested for HAE.

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