What is hereditary angioedema (HAE)?

Hereditary angioedema (HAE) is a rare genetic disease that affects how the immune system controls inflammation. It causes repeated episodes of severe swelling of the skin, airway, and gastrointestinal system. Worldwide, 1 in 10,000 to 50,000 people have HAE.

Some people with HAE start noticing symptoms around puberty. If untreated, swelling attacks can increase. The timing, frequency, and severity of these attacks can be unpredictable and vary throughout a person’s life. Medication can reduce the frequency of attacks and make them less severe.

HAE can be difficult to diagnose because its symptoms overlap with allergic reactions and common gastrointestinal illnesses. These include gastroenteritis, irritable bowel syndrome, appendicitis, diverticulitis, and pancreatitis.

Untreated HAE attacks can disrupt your daily life. So it’s important to recognize HAE symptoms. The symptoms can even be life-threatening if throat inflammation closes your airway.

Some HAE attacks will start with early warning symptoms several hours before swelling begins. These symptoms may include:

  • painless, non-itchy rash
  • tingling skin
  • skin tightness
  • fatigue
  • irritability
  • sudden mood changes
  • anxiety

During an HAE attack, swelling can happen in a variety of places. This includes the hands, feet, genitals, gastrointestinal (GI) tract, and throat. Throat swelling is a medical emergency. You should seek treatment at the first sign of this symptom.

Skin swelling

The most common symptom of HAE is swelling that starts with skin tightness and tingling. Then it progresses to extreme, painful swelling. If untreated, this swelling usually decreases over one to three days. These symptoms can prevent you from participating in normal activities. For example, your fingers may swell so that they can’t bend and your feet may become too swollen to put on shoes.

Skin swelling from HAE can affect your:

  • hands
  • feet
  • face and mouth
  • genitals
  • buttocks

Abdominal swelling

Swelling in the GI tract makes up half of all HAE attacks. When the GI tract is affected during an HAE attack, it can lead to:

  • severe stomach pain
  • nausea
  • vomiting
  • diarrhea
  • dehydration

In people with undiagnosed HAE, abdominal symptoms can lead to unnecessary surgeries if they’re confused with conditions such as appendicitis, ovarian torsion, or ruptured ovarian cysts.

In severe cases, the loss of body fluids from abdominal swelling can lead to hypovolemic shock. This is a life-threatening condition that requires immediate medical attention.

Throat swelling

Throat swelling is the most severe and dangerous symptom of HAE. About 50 percent of people with HAE have had at least one throat-swelling event.

If you think your throat is swelling or if you have trouble breathing, swallowing, or talking, you should call 911. Throat inflammation can be fatal if it closes your airway. It usually takes several hours for these attacks to develop, but sometimes they happen faster.

Symptoms of throat inflammation include:

  • change in voice quality or hoarseness
  • difficulty swallowing
  • difficulty breathing

Unlike for an allergic reaction, antihistamines and corticosteroids can’t be used to treat throat swelling caused by HAE.

If you treat a throat-swelling attack at home, you should still seek immediate medical care to make sure your airway is safe.

While some HAE attacks occur without explanation, certain events or activities can trigger HAE symptoms. Recognizing what triggers your attacks can help you avoid or manage them. These triggers include:

  • anxiety or stress
  • dental work
  • surgery
  • medications
  • illnesses
  • certain foods
  • physical or environmental factors

Though HAE is a lifelong condition, its symptoms are manageable with the proper treatment plan and medications. You can take medication regularly to prevent attacks. Treating attacks as soon as you recognize the symptoms also helps reduce their impact on your life.

Keeping a log or diary to understand your symptoms and what triggers them will also help you and your doctor develop a plan to manage your HAE. With the right management, you can lead a full, active life with HAE.