volatile,but often pronounced episodes of swelling, predominantly on the face, but also on the hands, feet, or in the airway area: Such symptoms speak for angioedema. This usually occurs in the context of an allergic reaction, a congenital disorder is much less common. Then, however, additional gastrointestinal complaints usually occur . The swellings are caused by water accumulation ( edema ) in the subcutaneous tissue; face angioedema was previously known as Quincke’s edema.
Forms of angioedema
First, two forms of angioedema have to be distinguished, since these two require different treatments in principle:
- Angiedema is caused either by the messenger substance histamine ( histamine-mediated angioedema ) , which is released in the event of an allergy or an intolerance reaction to medicines , for example . This mechanism is similar to that which occurs with hives (urticaria).
- The inadequate function of a certain molecule – the C1 inhibitor ( angioedema due to C1 inhibitor deficiency – in short: AAE) – is much less common , which normally slows down the immune system in the event of uncontrolled reactions. This form is usually inherited and thus congenital ( hereditary angioedema – short: HAE). The acquired forms of this C1 inhibitor deficiency arise either as part of cancer of the lymphatic system or as a result of autoimmune diseases.
What are the causes of hereditary angioedema?
In patients with hereditary angioedema, the level of a protein called C1 esterase inhibitor is decreased in the blood plasma. This protein inhibits the first component of the complement system. The complement system, in turn, consists of a cascade of serum proteins that play an important role in the immune and inflammatory response of the human body.
This disorder is inherited – if a parent is affected, there is a 50 percent risk that a child will inherit the condition.
Who is affected and why?
The age at the onset of HAE symptoms varies widely, but there is a frequency peak in the first and a second in the second decade of life. About 75 percent of patients are symptomatic when they reach the age of 20. Attacks appear to occur frequently during puberty and early adulthood. For example, taking the contraceptive pill is reported to trigger the first HAE attack in previously unremarkable patients .
Another triggering factor can be an infection, for example the not uncommon viral infection mononucleosis (Pfeiffer glandular fever).
The attacks can also occur without recognizable external causes, stress, fear or minor injuries can provoke them. Dental treatments can help, for example, to cause swelling of the mucous membranes in the airways. Other triggers have also been described (for example, hand swelling after mowing the lawn, writing, hammering, etc.).
Hereditary angioedema during menstruation and pregnancy
In women, menstruation and pregnancy seem to have an effect on the activity of the disease. Some women report an increase in the number of attacks during their menstrual periods.
During pregnancy, some patients report an increased frequency of attacks, while others report a reduced frequency.
The use of oral contraceptives (birth control pills, especially those with a high estrogen content) or hormone-containing intrauterine devices appears to increase the frequency and severity of swelling of the mucous membranes.
Hereditary angioedema: symptoms
The typical symptoms of HAE disease are the temporary appearance of painful, non-itchy swellings that are colorless and are found in the subcutaneous tissue or acute abdominal pain with no apparent other cause.
Patients often report a feeling of tension at the point where the edema occurs about 30 minutes to a few hours later. The swelling lasts for at least four – on average between 24 and 72 hours – but can also last longer in individual cases.
Frequency of hereditary angioedema
The frequency of HAE attacks varies enormously. Some patients are symptom-free for a long time, then swelling occurs at short intervals. Other patients suffer attacks at shorter, regular intervals.
Complications from hereditary angioedema
The seizures are particularly dangerous if they occur in the area of the airways. In this case, the mucous membrane can occlude the airways and make an emergency tracheotomy (tracheal incision) necessary. Untreated swelling of the mucous membrane in the trachea is one of the main causes of death in HAE patients.
In the past, if HAE was not recognized, mortality rates of 25 to 30 percent of patients have been observed. Therefore, in the event of swelling of the mucous membrane in the larynx area, immediate administration of C1 esterase inhibitor concentrate and medical treatment are absolutely necessary.