Frequently Asked Questions

What is HAE?

Hereditary Angioedema (HAE) is a very rare and potentially life-threatening genetic condition. HAE occurs in about 1 in 10,000 to 1 in 50,000 people. HAE symptoms include episodes of edema (swelling) in various body parts including the hands, feet, face and airway. HAE patients have a defect in the gene that controls a blood protein called C1 Inhibitor. The genetic defect results in production of either inadequate or non-functioning C1-Inhibitor protein. Read more about HAE at

How is HAE Diagnosed?

Most cases of angioedema turn out to not be HAE, because most swelling attacks are typically allergic reactions, or swellings caused by something other than C1-inhibitor deficiency.

Laboratory analysis of blood samples or genetic testing is required to establish the HAE diagnosis. There are two specific blood tests that confirm HAE:

  • C1-inhibitor quantitative (antigenic)
  • C1-inhibitor functional

To read more about HAE diagnosis go to

What does the US HAEA do?

The US HAEA is a non-profit patient advocacy organization dedicated to serving persons with angioedema. We provide patients and families with a support network and wide range of services.