Phenytoin hypersensitivity syndrome: a case report

We report a life-threatening case of phenytoin hypersensitivity syndrome, a rare reaction primarily characterized by fever, skin eruptions, lymphadenopathy, eosinophilia, and hepatotoxicity. The reaction developed in a 27-year-old black man with surgically corrected tetralogy of Fallot who was treated with phenytoin for one month for exercise-induced sustained ventricular tachycardia. Phenytoin therapy was discontinued and the patient was treated with intravenous methylprednisolone; the therapy was later converted to oral prednisone. Clinical improvement was noted five days after admission and the patient was discharged on hospital day 14. This adverse reaction usually develops within six weeks of starting phenytoin therapy and may be fatal in up to 40 percent of the patients who develop hepatotoxicity. Early recognition of this relatively rare reaction is essential to prevent serious and potentially fatal complications.