Hereditary angioedema is a very rare immune system disorder that causes blood, lymph, and other bodily fluids to build up in certain areas of the body. People with the disorder may experience frequently recurring episodes of facial, hand, foot, or abdominal swelling. Hereditary angioedema may also cause gastrointestinal problems and potentially deadly airway constriction. Treatment options are limited for the disorder since traditional anti-inflammatory medications are ineffective. People with severe hereditary angioedema may need regular blood transfusions to control symptoms and prevent serious complications.
Proteins called C1 esterase inhibitors normally regulate the flow of blood and fluid through different types of body cells. In the case of hereditary angioedema, C1 proteins are either in very low supply or inactivated due to a genetic mutation. Low or abnormal C1 proteins lead to fluid buildup underneath the skin and in some organs. The condition is categorized as autosomal dominant, meaning that it can be inherited if just one parent carries a defective gene. Even though C1 deficiencies are present at birth, symptoms do not usually arise until adolescence or early adulthood.
The most common symptoms of hereditary angioedema are swelling and redness in the extremities or face. In most cases, swelling is not accompanied by itching, burning, or other symptoms normally associated with skin rashes. Symptomatic episodes can last anywhere from one day to several weeks at a time, and attacks reoccur somewhat spontaneously in most patients.
If C1 deficiency is severe, the lining of the gastrointestinal tract may be affected as well. When the intestines swell, a person can experience painful cramps, distension, loss of appetite, and nausea. The lungs and airways are only rarely involved, but complications can lead to life-threatening airway obstruction, heart attack, or stroke.
Doctors diagnose hereditary angioedema by reviewing symptoms, examining patches of swollen skin, and analyzing blood tests. Blood samples can be screened for usual C1 counts and other signs of an autoimmune disorder. Diagnostic imaging tests may be necessary as well if intestinal or lung damage is suspected.
When hereditary angioedema is limited to skin involvement, treatment is not always necessary. A doctor may prescribe anti-inflammatory drugs such as corticosteroids to help alleviate immediate symptoms, but there is no clear long-term cure. Hospitalization and blood transfusions are necessary if the condition becomes very serious. Patients who are at risk of frequent, severe attacks may need plasma transfusions on a regular basis throughout their lives as well to level out C1 concentrations.