Drug-induced vasculitis.

Vasculitis resulting from drug use includes a wide variety of clinical and pathologic conditions that are, in general, empirically defined and poorly understood. Further complicating our grasp of these disorders are ambiguous terms such as hypersensitivity vasculitis, allergic vasculitis, leukocytoclastic vasculitis, serum sickness, and others, which are often used interchangeably without clear definition. The clinical picture varies widely from self-limiting to progressive and even fatal illness. These syndromes have now been reported in association with newer classes of therapeutic agents including biologic response modifiers. Vasculitis affecting the central nervous system may be related to a variety of drugs and remains one of the more important syndrome sets within the spectrum of drug-induced vasculitis. These disorders are clinically important, because removal of the offending drug often is associated with regression of the vasculitic condition.