Treatment of polymorphous light eruption with nicotinamide: a pilot study

Abstract
In a pilot study, 42 patients suffering from polymorphus light eruption (PLE) were treated with oral nicotinamide, 3 g daily for 2 weeks. Twenty-five patients remained free from lesions despite extensive sun exposure. We suggest that an abnormality in tryptophan metabolism is important in the aetiology of PLE, and that nicotinamide administration partially corrects this.