Drug-induced lupus. The list of culprits grows.

More than 70 medications have been implicated as a cause of drug-induced lupus. The condition most commonly manifests with arthralgias and fever. The most important laboratory feature is an elevated antinuclear antibody titer, which often corresponds to the presence of antihistone antibodies. Fortunately, the course of drug-induced lupus is more benign than that of idiopathic systemic lupus erythematosus. Clinical resolution generally occurs after withdrawal of the offending agent. The patient described here exemplifies the importance of maintaining a heightened awareness of this uncommon disorder. For him, delayed diagnosis of drug-induced lupus resulted in prolonged discomfort, restriction of daily activities, and unnecessary therapeutic intervention.