People with a condition called Hereditary Angioedema live in constant fear that their disease will flare up, causing extreme swelling in the face, abdomen or limbs. We’ll talk to an expert about the disease, and see a new way to help treat HAE attacks.

Hereditary angioedema is a genetic condition caused by a defective gene for a blood protein called C1 inhibitor. This protein regulates the biochemical processes involved in fighting disease, controlling inflammation and coagulation of blood. In the most common type, type I (accounting for 85 percent of cases), patients have low levels of the C1 inhibitor.

Those with type II have normal levels of the protein, but it doesn’t function properly. Having inadequate levels or nonfunctioning C1 inhibitor causes the body to produce an excessive amount of a chemical called bradykinin. The chemical causes the blood vessels to dilate and leak fluid into the surrounding tissues. As the fluid accumulates, it leads to swelling and pain.

The swelling associated with hereditary angioedema can occur in the face, hands, feet, throat, gastrointestinal tract or genitals. Timothy Craig, D.O., Allergist/Immunologist with Penn State Milton S. Hershey Medical Center in Hershey, PA, says the symptoms typically last for about three days and recur periodically.

An attack may occur anywhere from once a year to as frequently as two or more times a month. The swelling can be very painful and disabling, preventing patients from being able to work or participate in regular activities. Abdominal swelling may also lead to nausea, vomiting and diarrhea. Of most concern is throat swelling, which can block the airways and cause death from asphyxia.

Hereditary angioedema is a relatively rare condition. The US Hereditary Angioedema Association estimates it occurs in about 1 out of every 10,000 to 50,000 people. If one parent has the defective gene a child has a 50 percent chance of inheriting the defective gene. In about 25 percent of patients, there is no family history and the disease is most likely caused by a mutation of the C1 inhibitor gene.

Swelling episodes associated with hereditary angioedema are unpredictable. Thus, patients often worry about new attacks. Some people don’t travel because they worry about the ability to get immediate medical treatment during an episode, especially for throat swelling. Many miss a considerable amount of work, advancement opportunities or, in some cases, lose their jobs.

Patients learn to recognize and limit exposure to triggers, like anxiety, stress, minor trauma, illness or surgery. For women, use of estrogen and onset of menstruation can trigger an attack. A class of blood pressure medication, ACE inhibitors, is also a common trigger. Researchers report about 87 percent of patients have “warning signs” of an impending attack, like rash, tingling sensation or numbness in the area of swelling, unusual fatigue and muscle aches.

There is no cure for hereditary angioedema. Researchers estimate the average costs of treatment/missed work for patients with the condition are $42,000 annually.

An older treatment for hereditary angioedema is androgen. However, these drugs must be used cautiously. Higher doses can cause acne, weight gain and unwanted hair growth. Craig says the drugs can also increase the risk for hepatitis, liver cancer, high cholesterol and heart disease.

Over the past few years, the FDA has approved three other drugs for hereditary angioedema. Cinyze™ is an intravenous medication that can be prevent many attacks. Craig says the medication is given about twice a week and replaces the defective protein. It cuts the number of attacks by about half. When symptoms occur, they tend to be less severe and last for a shorter period of time. Berinert® is another intravenous medication specifically approved for facial and abdominal swelling.

The newest medication for hereditary angioedema, Kalbitor®, was approved in December 2009. It’s given through subcutaneous injection. Craig says this drug works very rapidly, usually providing symptom relief within 30 to 40 minutes. It prevents the bradykinin chemical from becoming activated, allowing the cells in the blood vessel walls to maintain their integrity and stopping leakage of fluid. A small number of people who get Kalbitor have an allergic reaction to the drug, so it must be given in the doctor’s office or emergency room.

Craig hopes patients who have had good results with Kalbitor will eventually have access to a self-injecting option. That would enable patients to start treatment soon after signs of an attack appear. According to Craig, starting treatment early in the attack usually lessens the severity of symptoms.

For general information on hereditary angioedema:
US Hereditary Angioedema Association

HAE Hope