Necrotizing lymphadenitis associated with the phenytoin-induced hypersensitivity syndrome

A 32-year-old black female was started on phenytoin for seizure prophylaxis following the clipping of an aneurysm. This was stopped after 3 weeks when she developed a generalized skin rash. Over the next week she developed fever, sore throat, dysphagia, and headache. She had an erythematous throat with white exudates on the right tonsil and 1 to 3 cm firm, tender lymphadenopathy in multiple regions. Blood, throat swab and cerebrospinal fluid studies were negative for bacterial or viral infections, except for elevated liver enzymes. CT scan of chest, abdomen, and pelvis showed no lymphadenopathy. Lymph node biopsy suggested necrosis but no evidence of infection, granuloma, or lymphoma. Her lymphadenopathy resolved spontaneously and liver enzymes normalized in 3 weeks. Hypersensitivity syndrome due to antiepileptics manifests as fever, rash, generalized lymphadenopathy, and probably represents a T-cell mediated drug reaction. This reaction may persist despite cessation of the drug, and it may engender expensive evaluation. Careful observation up to 3 weeks after drug cessation may be the best management.