Rates of allergic sensitization and irritation to oxybenzone-containing sunscreen products: a quantitative meta-analysis of 64 exaggerated use studies

Background/purpose: Oxybenzone is an active ingredient found in sunscreen products that absorbs a broad spectrum of ultraviolet (UV) light, with absorbance peaking in the UVB region and extending into the UVA region. Although the overall incidence of sensitization and irritation associated with oxybenzone in the general population remains unclear, a few studies have reported on the incidence in specific circumstances. However, the relevance of these studies to the general population is limited, because the sample populations reported in these papers generally have consisted of individuals who sought medical attention for preexisting skin conditions. Therefore, the reported incidence of allergic reactions to oxybenzone in these studies may be overestimated as related to the general population. The objective of this meta-analysis was to determine the safety of oxybenzone in participants recruited from the general population. Methods: The data from 64 unpublished exaggerated use human repeat insult patch tests (HRIPT) and photoallergy (PA) studies sponsored by Schering-Plough HealthCare Products Inc. between 1992 and 2006 were aggregated and analyzed to evaluate the irritancy and sensitization potential of sunscreen products containing oxybenzone at concentrations between 1% and 6%. Results: Forty-eight of 19 5 7 0 possible dermal responses were considered to be suggestive of irritation or sensitization; the mean rate of responses across all formulations was 0.26%. Sensitization rates did not correlate significantly with oxybenzone concentration. The available re-challenge data indicated that only eight of these responses were contact allergies from oxybenzone, and the mean rate of contact allergy to oxybenzone was 0.07%. The source of the skin responses was not confirmed for 15 subjects who were lost to follow-up. However, all subjects were given the opportunity to participate in follow-up testing. Conclusion: Our data indicate that sunscreen products formulated with 1-6% oxybenzone do not possess a significant sensitization or irritation potential for the general public. Furthermore, these data suggest that the incidence rate implied in the published literature overestimates the actual incidence of sensitization/irritation due to oxybenzone-containing sunscreen products in the general population.