If you’re trying to get a grasp on what this rare disease is, you’ve come to the right place. Let’s start by covering some of the basics.
Hereditary angioedema, or HAE, is a rare disease of the immune system that causes spontaneous swelling throughout the body. In fact, it’s so rare that it only affects an estimated 1 in 50,000 people around the world.
The “angioedema” in HAE refers to a swelling of the skin that is similar to hives. But unlike hives, the swelling in HAE is sometimes below the skin’s surface and is not itchy. Often times, the swelling can be rather painful and severe.
If you have HAE, you may have started experiencing symptoms around puberty, but the swelling can sometimes start in childhood. On average, untreated HAE patients have sudden attacks (or symptom flare-ups) every 7-14 days, each generally lasting 2-5 days before resolving on their own. Most patients will continue to have HAE attacks throughout their lives, but some may find that their symptoms occur less often as they get older.
HAE attacks are unpredictable and can happen anywhere on the body, but they tend to affect three main places on the body:
HAE is "hereditary" because it is caused by a genetic defect that is passed through families. When a parent has HAE, there is a 50% chance that his or her child will inherit the disease.
A typical patient with HAE often has several family members with the condition. However, in 25% of HAE patients, HAE is not inherited, but caused by a random mutation of the C1 esterase inhibitor (CI-INH) gene. In other words, you can have still have HAE even if no one in your family has the disease. Keep in mind, though, that once the mutation occurs, it has the potential to be passed on to your children.