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

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).

There is usually no itching or hives. Swelling of the gut can cause intestinal cramping. If swelling closes the airways, it can be deadly. 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 just 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 have been shown to trigger certain 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 leads to vomiting, dehydration, diarrhea, pain, and occasionally shock

Blood tests will be done to check the levels of C1 inhibiting factor, C4,and C2.

Antihistamines and other related treatments are of limited benefit in hereditary angioedema.

Attenuated androgens, which are derivatives of normal sex hormones, can reduce the frequency and severity of attacks.

Once an attack occurs, treatment includes pain relief and fluids given by an intravenous (IV) line.

Helicobacter pylori, a bacteria found in the stomach, can trigger abdominal attacks. Getting rid of the bacteria with antibiotic therapy decreases these abdominal attacks.

Hereditary angioedema can be life threatening and treatment options are limited. How well a person does depends on the individual's specific symptoms.

Swelling of the airways may be deadly.

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 beneficial for prospective parents with a family history of hereditary angioedema.

Weiler CR, van Dellen RG. Genetic test indications and interpretations in patients with hereditary angioedema. Mayo Clin Proc. 2006;81(7):958-972.

Levi M, Choi G, Picavet C, Hack CE. Self-administration of C1-inhibitor concentrate in patients with hereditary or acquired angioedema caused by C1-inhibitor deficiency. J Allergy Clin Immunol. 2006;117(4):904-908.

Bork K, Barnstedt SE. Treatment of 193 episodes of laryngeal edema with C1 inhibitor concentrate in patients with hereditary angioedema. Arch Intern Med. 2001;161(5):714-718.

Farkas H, Fust G, Fekete B, Karadi I, Varga L. Eradication of Helicobacter pylori and improvement of hereditary angioneurotic oedema. Lancet. 2001;358(9294):1695-1696.

Visy B, Fust G, Bygum A, et al. Helicobacter pylori infection as a triggering factor of attacks in patients with hereditary angioedema. Helicobacter. 2007;12(3):251-257.