First case of acquired functional C1(-) INH deficiency: association with angioedema during Churg and Strauss vasculitis.

This report deals with the first case of acquired functional C1(-) INH deficiency with normal antigenic C1(-) INH level which was detected in a young girl with angioedema and Churg and Strauss vasculitis. This complement abnormality was associated with slightly depressed levels of CH50, C4 and C2, but a normal level of C3, and high levels of total IgE and IgM rheumatoid factors. Finally, most of these abnormalities disappeared after corticosteroid therapy and clinical improvement.