Arthritis as a rare side effect of phenytoin therapy.

Anticonvulsant hypersensitivity syndrome is an uncommon side effect of phenytoin. It is characterized by fever, skin reactions, lymphadenopathy, and severe multiorgan involvement. Atypical clinical features have rarely been described. We observed a unique case of anticonvulsant hypersensitivity syndrome in a 77-year-old woman in whom fever and monoarthritis were the main clinical features. Symptoms dramatically subsided after phenytoin withdrawal.