UVA sensitivity and topical photoprotection in polymorphous light eruption

The efficacy of a non-PABA, non-benzophenone broad-spectrum sunscreen was investigated experimentally in 8 patients with polymorphous light eruption (PMLE). A UVA-SUN 2000 lamp, emitting high intensity UVA radiation was used to irradiate unprotected and sunscreen protected skin sites of the upper back of each patient. Morphological and histological skin changes were noted in non-protected test-sites, while no clinical or microscopic changes were observed in the sunscreen-treated test-sites. Low minimal erythema dose (MED) values for both UVA and UVB light were noted in several PMLE patients.