Immunopathology of the skin in acute poststreptococcal glomerulonephritis

The immunohistologic features of the skin were studied in 26 cases of poststreptococcal glomerulonephritis. Twenty-two patients had vascular and extravascular dermal deposition of IgG. Positive stains for C3 (eight patients). IgM (two patients), and fibrinogen (five patients) were confined to vessel walls. Staining with anti-IgA serum was uniformly negative. Circulating antiskin antibodies could not be detected. Extravascular accumulation of IgG has a widespread distribution in the dermal papillary layer that is highly characteristic. It was absent in 7 patients with chronic glomerulonephritis and in 11 patients with various other renal diseases. The described findings appear to occur consistently in acute poststreptococcal glomerulonephritis. The distinctive extravascular demonstration of IgG may prove to be valuable in the diagnosis of this entity.