Reproducible elevation of liver transaminases by topical 8-methoxypsoralen

We present a case of a 17-year-old woman with vitiligo who had no known previous liver diseases nor any exposure to concurrent hepatotoxic drugs and who developed a liver injury while on topical methoxypsoralen photochemotherapy (PUVA). The reaction, manifested by elevated liver enzymes, was provoked on 3 consecutive occasions, and on the last one, with 1% methoxypsoralen lotion only. Although the exact mechanism of liver injury in our patient is unknown, it seems to be an idiosyncratic hypersensitivity reaction to topically applied methoxypsoralen.