BENZOPHENONES IN HIGH SPF SUNSCREENS MAY CAUSE PHOTOALLERGIES
BENZOPHENONES IN HIGH SPF SUNSCREENS MAY CAUSE PHOTOALLERGIES, according to a preliminary study of four patients by Columbia University dermatologists. The report, presented at the American Academy of Dermatology 47th annual meeting in Washington Dec. 3-8, found that benzophenones (designated as oxybenzone, or 2-hydroxy-4-methoxybenzophenone) can produce skin sensitization, including photoallergies. The report suggests that "such reactions will become more commonplace since oxybenzone is by far the most frequently used agent" in sunscreens exceeding a sun protection factor (SPF) of 8. The study pointed out that potential benzophenone photoallergy is not as well-known in the U.S. as sensitivity to PABA and its esters. "The occurrence of these reactions is not widely appreciated" even though benzophenone reactions have been reported in Europe as well as in an American six-year study, the report noted. The preliminary report is based on a four-patient study of sunscreen usage. Each patient was using a benzophenone-containing sunscreen to treat an already existing skin condition. Two of the patients' sunscreen use was physician-prescribed. In each case, after using the benzophenone sunscreen the skin condition worsened. The study results were based on photo-patch tests with benzophenone 2% and PABA 1%. Both with and without exposure to UVA light, moderate to pronounced photoallergy reactions were recorded for benzophenone in all four patients. By comparison, a mild reaction was recorded for PABA 1% in only one patient. None of the patients was previously PABA-sensitive. In addition to benzophenone and PABA, 14 other known photoallergans - including the sunscreen octyldimethyl-PABA 3% - were tested on each of the patients with no response. The preliminary study, "Photoallergy to Benzophenone," was conducted by Elizabeth Knobler, M.D., et al., at the Columbia University Department of Dermatology's Environmental Dermatology Unit. The potential for high SPF sunscreens to cause skin photosensitization and chronic dermal toxicity was a major topic of discussion at the FDA's Jan. 26 panel meeting on sunscreens. Several commentators maintained that sunscreens with SPFs over 20 increase the likelihood of irritation. However, comments to the agency argue that formulation advances have produced products with lower levels of active ingredients that eliminate the potential for irritation.
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