Oral carotenoid treatment in polymorphous light eruption: a cross-over comparison with oxychloroquine and placebo.

During 3 consecutive summers, patients from a total group of 40 persons with polymorphous light eruptions (PMLE) participated in a randomized, double-blind, cross-over study comparing the sun-protective effect of placebo capsules, a chloroquine derivative (200 mg daily of oxychloroquine), and a carotenoid preparation (betacarotene and canthaxanthine in a daily total dose of 100 mg). A total of 35 carotenoid, 38 chloroquine, and 27 placebo treatment periods were registered. Full freedom from sun sensitivity was obtained during 6 carotenoid and 8 chloroquine periods, but never with placebo treatment. In addition, a partial sun tolerance was induced in 17 carotenoid periods, 15 chloroquine periods, and in 14 placebo treatment periods.