Lamotrigine-Induced Rash After Sun Exposure

Mr. A, a 42-year-old man with a diagnosis of schizoaffective disorder, bipolar type, was hospitalized in our clinic after a recurrence of his disorder that was induced by discontinuing his drug therapy. He received lamotrigine, 25 mg t.i.d., coadministrated with haloperidol, 20 mg b.i.d. His dose of lamotrigine was titrated gradually within a month. One year later, during Mr. A’s last hospitalization, his dose of lamotrigine was raised to 100 mg b.i.d., whereas his dose of haloperidol stayed the same. He showed a marked regulation of his mood fluctuations after his discharge, and he also experienced a relatively satisfying vocational and social adjustment. Three months later, an acute maculopapular rash with itching appeared, which subsided after his lamotrigine treatment was interrupted. The day before the rash appeared, he had been exposed to sunlight while doing agricultural work.

Ms. B, a 30-year-old woman with a diagnosis of bipolar disorder type I (her most recent episode was manic), received lamotrigine as a prophylactic therapy. Her lamotrigine dose was titrated gradually within 1 month up to 100 mg b.i.d. Six months later, while her mood had a normal fluctuation, she developed an acute maculopapular rash with itching. The day before the rash appeared, she had been exposed to the light of a solarium. The rash subsided after her treatment with lamotrigine was discontinued.