Hereditary angioedema is a rare but serious problem with the immune system that is passed down through families. It causes swelling, particularly of the face and airways, and abdominal cramping.
See also: Angioedema
Causes, incidence, and risk factors
Hereditary angioedema (HAE) is caused by low levels or improper function of a protein called C1 inhibitor. This problem affects the blood vessels. People with hereditary angioedema can develop 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. However, 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 attacks of hereditary angioedema.
- 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.
Signs and tests
Blood tests (ideally done during an episode):
- C1 inhibitor function
- C1 inhibitor level
- Complement components C4 and C2
Antihistamines and other treatments used for angioedema are of limited benefit in hereditary angioedema. 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, but rarely, the swelling will become worse.
Androgen medications, such as danazol, can reduce the frequency and severity of attacks. These medicines tell your body to make moreC1 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 h. pylori willdecrease 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.
Calling your health care provider
Call or visit your health care provider if you are considering having children and have a family history of this condition, or 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. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 260.
Wasserman SI. Approach to the person with allergic or immunologic disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 257.