Abstract
A 61-year-old man suffering from epilepsy was treated with lamotrigine and valproic acid. He had also been suffering from liver dysfunction caused by anticonvulsants for 1 year. He had a fever of over 38 ℃ on the 26 th day of the treatment with lamotrigine and valproic acid, followed by disseminated erythema with scales. He had a rash and scales over his whole body including his face on the 29 th day. He visited our clinic on the 36 th day. Based on the clinical features, drug-induced
hypersensitivity syndrome (DIHS) caused by lamotrigine was suspected. Hence, lamotrigine was stopped and oral prednisolone (20 mg/day) was administered. His anti-HHV-6 IgG titer rose from 20× to 160× during the 3 weeks from the initial visit, suggesting the reactivation of HHV-6. A drug-induced lymphocyte stimulation test for lamotrigine was positive. The diagnosis of DIHS was made based on the standard criteria, excluding lymphadenopathy. It has been reported that most cases of severe drug eruption induced by lamotrigine were caused by either an overdose of the drug or its use in combination with valproic acid. In our case, despite the treatment following the recommended dosages of lamotrigine when combined with valproic acid, the patient suffered from DIHS. In addition, his symptoms recurred after the dose of prednisolone was decreased. Consequently, it is difficult to anticipate the occurrence of DIHS, even though we pay attention to the dosage of lamotrigine or other drugs used in combination with lamotrigine.
