title: Photoirritation: a new photobiologic phenomenon induced by long wavelength UVA radiation in hairless mice treated with broad-spectrum sunscreens.
abstract: While assessing the protective effect of broad-spectrum sunscreens against chronic UVA radiation, we observed a paradoxical worsening of skin damage with one product. To further examine this finding, five proprietory broad-spectrum sunscreens were applied to albino hairless mice irradiated thrice weekly for 32 weeks with a UVASUN lamp (> 340 nm). Appropriate age-matched controls were included. After approximately 12 weeks, two sunscreens induced a marked dermatitis. Biopsies showed damage greatly exceeding that found in UVA-irradiated, unprotected controls. Histologically, elastic fibers were hyperplastic, coalescing into elastotic clumps. Glycosaminoglycans also increased. Collagen damage was notable since UVA alone does not induce a histologic change. Electron microscopy confirmed these findings. Two other sunscreens provided nearly complete protection. Against chronic UVB radiation, the two UVA photoirritating sunscreens provided substantial protection. Since the UVA sunfilter, oxybenzone, was the same in all sunscreens, we postulate that an irritating component of the vehicle was responsible for the UVA-induced photoirritation. The fifth sunscreen produced severe damage with UVB and UVA.
authors.affiliation: Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia 19104-6142, USA.
authors.forename: L H
authors.initials: LH
authors.lastname: Kligman
authors.forename: P
authors.initials: P
authors.lastname: Zheng
authors.forename: A M
authors.initials: AM
authors.lastname: Kligman
mesh_terms: D000818:Animals; D001577:Benzophenones / Q000494:pharmacology; D001706:Biopsy; D016022:Case-Control Studies; D003094:Collagen / Q000187:drug effects / Q000528:radiation effects; D017454:Dermatitis, Photoallergic / Q000209:etiology* / Q000473:pathology; D004547:Elastic Tissue / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D005260:Female; D006025:Glycosaminoglycans / Q000528:radiation effects; D006168:Guinea Pigs; D006965:Hyperplasia; D007509:Irritants / Q000009:adverse effects; D051379:Mice; D008812:Mice, Hairless; D008854:Microscopy, Electron; D014677:Pharmaceutical Vehicles / Q000009:adverse effects; D011829:Radiation Dosage; D012867:Skin / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D013473:Sunscreening Agents / Q000009:adverse effects*; D014466:Ultraviolet Rays / Q000009:adverse effects* / Q000145:classification
chemical_list: D001577:Benzophenones; D006025:Glycosaminoglycans; D007509:Irritants; D014677:Pharmaceutical Vehicles; D013473:Sunscreening Agents; D003094:Collagen; C005290:oxybenzone