05/04/2026
What Is Hereditary Angioedema (HAE)?
Swelling can be scary, especially when it happens suddenly. Most of the time, swelling of the skin (like lips, eyes, or hands) is caused by something common, like allergies or a virus. But in rare cases, swelling may be due to a condition called hereditary angioedema, or HAE for short. HAE is a genetic condition, which means it can run in families. It happens when the body is missing or not using a protein that helps control swelling. Because of this, the body can swell suddenly without a clear reason. Thankfully, most swelling is not HAE. But if swelling keeps happening, lasts a long time, or does not respond to allergy medicines, it’s important to look deeper.
HAE causes episodes of swelling in different parts of the body. This can include the face, lips, eyelids, hands, feet, stomach, or throat. Unlike typical allergic or viral-induced swelling, HAE swelling usually does not itch, usually does not come with hives, and can last longer (usually 2-5 days). HAE is rare, but it can be serious. The good news is that there are plenty of safe and effective treatments for HAE. If you have recurrent swelling, a family history of swelling, or swelling that does not respond to allergy treatments - you should see an allergist!