Hypersensitivity vasculitis and systemic lupus erythematosus induced by anticonvulsants.

Vasculitis can be a systemic manifestation of hypersensitivity to many drugs, among them anticonvulsants. The clinical manifestations include rash and renal, hepatic, and pulmonary involvement. Diagnosis is based upon clinical findings and a characteristic biopsy showing granulocytic and sometimes eosinophilic infiltrates around small blood vessels, especially venules. A severe form of hypersensitivity vasculitis, with extensive visceral involvement and poor prognosis, has been encountered very rarely following phenytoin and in isolated cases following carbamazepine and trimethadione administration. Drug-induced systemic lupus erythematosus is much more frequent, with distinct clinical and laboratory abnormalities. The syndrome was described following treatment with most anticonvulsants in clinical use--phenytoin, carbamazepine, ethosuximide, trimethadione, primidone, and valproate, but not phenobarbital or benzodiazepines. The early recognition of these syndromes as being related to drugs is important, because they usually remit upon withdrawal of the offending agent.