Controlled therapeutic trials in polymorphic light eruption

A series of controlled trials of treatments for polymorphic light eruption (PLE) with oral beta-carotene, ketoprofen and chloroquine, and topical benzimidazole sunscreen cream is described. Clinical features were recorded using diary cards filled out by the patients, and exposure to UVR was measured individually in all patients with film badges. Symptoms were found to be dependent on exposure. None of the treatments proved very effective, but beta-carotene seemed to give significant slight protection against irritation and erythema, though this was not confirmed in a repeat study using a higher dose. Chloroquine seemed to protect slightly against irritation. As the degree of improvement with chloroquine and beta carotene is quite small, equivalent to a protection factor of 2, it is arguable whether these treatments as used here are worthwhile and in the case of chloroquine, with its risk of adverse side effects, whether it is justifiable. Other treatment and dose regimes are possible and further trials seem worthwhile. Our studies have helped to define the special difficulties in collecting objective data in PLE and should improve the methods for assessing treatment in the photodermatoses.