Leukocytoclastic vasculitis caused by sulfamethoxazole-trimethoprim.

Leukocytoclastic vasculitis is a rare, small-vessel vasculitis that can be caused by sulfamethoxazole-trimethoprim. Most presentations involve skin rash but serious systemic involvement is possible. The precise mechanism is unclear but genetic and immune-based tissue damage has been postulated. The rash often resolves with discontinuation of sulfamethoxazole-trimethoprim with or without steroids.