Hereditary angioedema (HAE) is a rare genetic condition that causes spontaneous swelling in various body tissues. The problem with HAE is that many people don't know HAE is causing their swelling until they are adults.
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Hereditary angioedema are episodes of edema - swelling - in body parts including the hands, feet, face and airway. While that can be a problem it can also be life threatening if they involve the airway. Patients may also experience strong abdominal pain, and nausea and vomiting.
Hereditary angioedema is caused by a defect in the gene that controls a blood protein called C1 inhibitor.
There are three types of HAE. Type I is the most common and it affects equally men and women. People who have type II HAE have normal levels of C1 but functioning poorly. This type of HAE also occurs equally among men and women. Type III is an extremely rare type of the condition that most often affects women only. The tests show the normal protein level but the person has symptoms of HAE.
Since HAE is a genetic condition that means a person needs to inherit one copy of a mutated gene to develop the disease and a parent with HAE has a 50 percent chance of passing it on to their child. However, if a spontaneous gene mutation occurs - in 20 percent of cases - a person will develop HAE and the mutated gene will pass to the children. Symptoms usually show up in childhood and get worse during time.
C1 inhibitor regulates the interactions of blood-based systems that play an important role in a reaction to a disease, inflammation and it is also doing its part in coagulation. When defective C1-Inhibitor doesn't do what it should, the body produces peptides that "tell" capillaries to release fluids into surrounding tissue and we have edema. Where the edema will occur, how often and how strong the bouts will be, that's different for every person.
Some patients experience warning signs before swelling begins and they are extreme fatigue, rash on arms or legs, headache, mood changes, muscle aches, tingling, and belly pain. What causes those attacks? It may be some minor injury, otherwise easy condition such as cold, stress, anxiety, physical activity such are typing on a computer, and medications can be the cause too.
Because HAE is very rare, it can be undiagnosed for years which can lead to many problems for a patient. Frequent abdominal pain may be diagnosed as psychosomatic, gastrointestinal edema may be treated with a surgery, the attacks can come and go, and airway obstruction may be attributed to an allergic reaction.
To be sure is it angioedema or HAE, in other words to be sure it's not about a typical allergic reactions or some other cause, laboratory blood analysis or genetic testing is necessary to establish the right diagnosis. If the diagnosis is wrong, for example corticosteroids have been prescribed for an allergy, that won't end well because they won't improve a HAE's patient condition.
Unfortunately, there is no cure for HAE, so all we can do is to try to prevent an attack and to keep the condition under control. There are several drugs that can be used.
Cinryze is used to prevent attacks and the patient can learn how to take it at home because it is in injections given in the vein. When the attack happens, Berinert and Ruconest are also given in the veins, Firazyr (icatibant) is injected under the skin - the patient can do that, and Kalbitor (ecallantide) is injected under the skin but in a doctor's office.
The most important thing to remember: If you have HAE and have difficulty breathing - take your medication for attacks and go to the doctor immediately. ■