Hereditary angioedema is a rare but serious problem with the immune system. The problem is passed down through families. It causes swelling, particularly of the face and airways, and abdominal cramping.
Angioedema is swelling that is similar to hives, but the swelling is under the skin instead of on the surface.
Hereditary angioedema (HAE) is caused by a low level or improper function of a protein called the C1 inhibitor. With HAE the blood vessels are affected. An HAE attack can result in rapid swelling of the hands, feet, limbs, face, intestinal tract, larynx (voicebox), or trachea (windpipe).
Attacks of swelling can become more severe in late childhood and adolescence.
There is usually a family history of the condition. But relatives may be unaware of previous cases, which may have been reported as an unexpected, sudden, and premature death of a parent, aunt, uncle, or grandparent.
Dental procedures, sickness (including colds and the flu), and surgery may trigger HAE attacks.
- Airway blockage -- involves throat swelling and sudden hoarseness
- Repeat episodes of abdominal cramping without obvious cause
- Swelling in the arms, legs, lips, eyes, tongue, or throat
- Swelling of the intestines -- can be severe and lead to abdominal cramping, vomiting, dehydration, diarrhea, pain, and occasionally shock
There is usually no itching or hives.
Exams and Tests
Blood tests (ideally done during an episode):
Antihistamines and other treatments used for angioedema do not work well for HAE. Epinephrine should be used in life-threatening reactions.
The most effective treatment is a C1 inhibitor concentrate, but this may not be available. A newer medicine called ecallantide may be used instead.
Fresh frozen plasma contains C1 inhibitor and will help an episode. In rare cases, the swelling can become worse with this treatment.
Androgen medications, such as danazol, can reduce the frequency and severity of attacks. These medicines help the body make more C1 inhibitor.
Once an attack occurs, treatment includes pain relief and fluids given through a vein by an intravenous (IV) line.
Helicobacter pylori, a type of bacteria found in the stomach, can trigger abdominal attacks. Antibiotics to treat the bacteria help decrease abdominal attacks.
Hereditary angioedema can be life threatening and treatment options are limited. How well a person does depends on the specific symptoms.
Swelling of the airways may be deadly.
When to Contact a Medical Professional
Call or visit your health care provider if you are considering having children and have a family history of this condition. Also call if you have symptoms of hereditary angioedema.
Swelling of the airway is a life-threatening emergency. If you are having difficulty breathing due to swelling, seek immediate medical attention.
Genetic counseling may be helpful for prospective parents with a family history of hereditary angioedema.
Dreskin SC. Urticaria and angioedema. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2012:chap 260.
Riedl MA. Creating a comprehensive treatment plan for hereditary angioedema. Immunol Allergy Clin N Am. 2013;33:471-485.
Reviewed By: Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.