Henoch-Schönlein vasculitis: direct immunofluorescence study of uninvolved skin.

Henoch-Schönlein purpura is a multisystem disease believed to be a consequence of entrapment of circulating IgA-containing immune complexes in blood vessel walls throughout the skin, kidney, and gastrointestinal tract. In this direct immunofluorescence study, twenty-five skin biopsy specimens from twenty patients with Henoch-Schönlein purpura were examined (9 from uninvolved, normal-appearing skin). A distinct stippled pattern of vascular fluorescence was found in 87% of lesion biopsies; 75% of these contained deposits of IgA. In uninvolved skin, seven (78%) showed immunoglobulin in vessel walls and six (67%) contained IgA, suggesting that immune complexes are deposited with equal frequency in normal-appearing and lesional skin of patients with Henoch-Schönlein purpura. Biopsy of uninvolved, rather than of purpuric, skin for direct immunofluorescence studies may be more helpful in confirming the diagnosis of Henoch-Schönlein purpura because tissue morphology is usually of better quality.