Granuloma annulare: direct immunofluorescence study.

Direct immunofluorescence studies were carried out in eleven specimens of granuloma annulare. The results (in all cases) indicate the presence of focal deposition of fibrin, localized primarily in the intervascular portion of the dermis, corresponding to the granulomatous and necrobiotic areas. These findings implicate the cellular mechanism of delayed hypersensitivity with focal involvement of the clotting system in the development of granuloma annulare lesion.