Hypocomplementemic urticarial vasculitis syndrome responsive to dapsone.

A 45-year-old woman with cutaneous urticaria-like lesions subsequently developed polyarthritis, glomerulonephritis, and chronic obstructive pulmonary disease. Biopsy of skin showed leukocytoclastic vasculitis of superficial capillaries. Biopsy of the kidney revealed mesangioproliferative glomerulonephritis, and lung biopsy revealed severe emphysema and thick-walled blood vessels with immunoglobulin deposition. Therapy with dapsone produced dramatic improvement of the patient's cutaneous vasculitis and arthritis. This case uniquely demonstrates the efficacy of dapsone for both the urticarial vasculitic and the arthritic components of this syndrome and reemphasizes the potentially severe pulmonary and renal complications.