Subcutaneous self‐injections of C1 inhibitor: an effective and safe treatment in a patient with hereditary angio‐oedema

A 25‐year‐old woman presented to our clinic with a history of recurrent swelling and abdominal symptoms for > 20 years. The patient's father was similarly affected. The patient was diagnosed with hereditary angio‐oedema (HAE) due to C1 inhibitor deficiency. This was initially managed with systemic androgens, but the symptoms of hyperandrogenism eventually became intolerable. Treatment with icatibant (an antagonist of bradykinin B2 receptors) was partially successful. We changed the therapy to prophylactic treatment with C1 inhibitor. Although the patient became completely symptom‐free under this regimen, she found the repeated intravenous injections unacceptable. Therefore, we changed the route of administration to subcutaneous injections of C1 inhibitor 1000 U in 10 mL twice weekly, using a subcutaneous infusion kit. Since that time (December 2013), she has remained completely free of symptoms under this regimen. To our knowledge, this is the first report documenting the efficacy and safety of subcutaneous injections of C1 inhibitor in a patient with HAE.