The physician can now recognize clinically and histopathologically the cutaneous manifestations of immune complex disease. The usual clinical environment in which this type of reaction occurs has been very specifically delineated. Studies of immunoglobulins, complement components, and B cells in the blood may confirm the nature of the reaction. Special studies of cryoproteins of C1q precipitin or radioimmunoassay procedures may demonstrate directly the complexes in the blood. Biopsy of skin for immunofluorescence is confirmative of the skin disease and the presence of immune complexes. Biopsy of normal skin may be prognostic and indicate severity of the disease. Lesions may be induced by epinephrine, trauma, and controlled imflammation for clinical and pathologic study and confirmation of diagnosis. Treatment of the disease with corticosteroids, sulfapyridine, nicotinic acid, and antimalarial drugs may be useful. Clofazimine is an intriguing experimental drug. Plasmaphoresis has worked well with some patients.
