Clinical suspicion is confirmed by measuring C1 esterase inhibitor activity or C1 esterase inhibitor antigen in blood plasma.
There is currently no cure for patients suffering from HAE attacks. Also, no therapy exists to date to completely prevent the attacks. Nevertheless, the symptoms can be relieved and the progression of the edema can be prevented. There are three types of therapies: Long-term prophylaxis, short-term prophylaxis, and treatment of acute attacks.
Who needs long-term prophylaxis?
Long-term prophylaxis is not needed by all patients with hereditary angioedema, but only by those who have one or more of the following:
- The mucosal swelling involves the respiratory tract
- The attacks occur more often than once a month
- The attacks or the disease is so severe that the patient can no longer participate in everyday life
Treatment option of first choice in hereditary angioedema.
The administration of C1 esterase inhibitor concentrate has been shown to be highly effective in both long-term prophylaxis and acute therapy – especially in patients with adverse reactions to previously used androgens. Intravenous administration provides the enzyme lacking in the patient directly. Undesirable severe side effects have not been reported to date.
Other treatment options: Androgens
Before C1-esterase inhibitor concentrate was the first-line agent, androgens were used. However, the multiple occurrences of benign liver tumors under the androgen danazol led to the substance’s withdrawal from the market in Germany in 2005.
Androgens are male sex hormones and have two main properties: they increase protein production in the human organism and influence the expression of male sexual characteristics (for example, increased hair growth, deeper voice).
Androgens and their effects on the organism
Androgens have been used successfully at doses ranging from 50 to 200 mg/day in the treatment of HAE, but they can cause virilization (“masculinization”) in women. In addition, they can cause irregularities in the menstrual cycle, weight gain, and mood changes, and can adversely affect liver function.
While androgens such as danazol can be obtained through international pharmacies, it is advisable to have such treatment initiated under supervision at an HAE treatment center. The use of androgens is contraindicated in children, as well as during pregnancy and in women of childbearing potential.
Short-term prophylaxis and therapy of acute attacks of HAE.
Short-term prophylaxis is particularly important when patients with hereditary angioedema require surgery or dental treatment. In this case, the missing enzyme C1 esterase inhibitor can be administered as an intravenous injection or infusion. The required dose is usually 500 to 1000 units of C1-esterase inhibitor concentrate.
In acute cases, the missing substance C1-esterase inhibitor concentrate is immediately administered intravenously. This causes rapid cessation of the attack and regression of the mucosal edema. An acute HAE attack does not respond to standard therapy for histamine-mediated angioedema.