Solar urticaria enhanced through clothing.

Solar urticaria is characterized by itching, erythema and wheeling immediately after exposure to radiation in the ultraviolet (UVB, UVA) and visible spectra. Although its exact mechanism remains unknown, evidence supports an immunologic pathogenesis. We describe an unusual patient with solar urticaria who had more severe involvement in skin irradiated with UVA light through white clothing. We propose that optical whiteners in clothing and detergents had absorbed UVA radiation, transforming it into visible light, which was responsible for the urticarial response.