If you’ve ever twisted your ankle or broken a bone, you probably noticed swelling in the tissue around the injury. This kind of swelling, which is called edema, is caused by fluid that collects in tissues and makes them puff up. People who have hereditary angioedema (HAE) experience similar kinds of swelling with no apparent cause or injury. HAE is a rare but potentially deadly condition that affects about 1 in 10,000 to 1 in 50,000 people.
What is HAE?
HAE is a condition that causes repeated episodes of swelling that can happen almost anywhere in the body. Common areas that may swell include the face, hands, feet, stomach and intestines, genitals, and throat. Attacks can come on unexpectedly and with varying degrees of swelling. One survey showed that just less than half of HAE patients had more than one attack a month. Approximately 40 percent said they had between six and 11 incidents of swelling a year. Untreated HAE can cause attacks every seven to 14 days that last between two and five days with more than 20 attacks each year.
Swelling caused by HAE takes place inside the tissue rather than on the surface of the skin, so it does not form welts or significant color changes. Patients describe the swelling as uncomfortable and often very painful, but not itchy like swelling caused by an allergy or insect bite.
Swelling caused by HAE can appear to attack random parts of the body. For example, swelling on the face can make one lip much larger than the other without affecting the rest of the face or mouth. In the hands and feet, swelling can make normal activities such as writing, holding objects, or walking difficult. Swelling in the abdomen can have more serious symptoms including extreme pain, nausea, vomiting, and diarrhea. The throat is the least common location for swelling, but it can be life-threatening if the airway swells enough to prevent breathing. This type of swelling requires immediate medical treatment.
Hereditary angioedema is called hereditary because the condition is most often genetically inherited within a family.