Hereditary angioedema: preliminary report on skin biopsy finding of fibrin and/or C4 through immunofluorescence.

Hereditary angioedema is considered an inherited disorder of the complement system, manifested by repeated crises of angioedema involving the skin, the gastrointestinal and respiratory tracts. Biopsies of normal skin obtained from 5 patients, diagnosed with hereditary angioedema, were found to be positive for fibrin and in one case also positive for C4. The sections stained with anti-fibrin serum showed fibrin deposits around isolated epidermal cells, while C4 staining revealed a homogeneous pattern along the epidermis. Fluorescence patterns and laboratory findings before and after treatment with danazol and/or anti-fibrinolytic treatment are reported.