Autoimmune acquired form of angioedema that responded to danazol therapy.

A 51-year-old man with recurrent episodes of angioedema was diagnosed as having autoimmune acquired angioedema, based on adult onset, lack of apparent family history, decreased activity of C1 esterase inhibitor (C1 INH) and CH50, decreased levels of serum C4 and Clq and the presence of autoantibodies to C1 INH. The danazol treatment relieved the symptoms of angioedema and increased the C1 INH activity and concentration with the normalization of CH50, C1q and C4 levels. To our knowledge, this is the first case of autoimmune acquired angioedema in Japan.