Facial disbiosis and UV filters

Abstract

Acne is a multifactorial inflammatory disease with a robust microbial component and numerous correlations with dysbiosis states. Furthermore, various factors are recognized as triggers for skin dysbiosis, including the use of certain cosmetics. Based on these arguments, we hypothesized that using photoprotective formulations could trigger dysbiosis and the occurrence of acne manifestations. To verify this assumption, six volunteers between 19 and 23 years of age, meeting all the inclusion criteria, received two applications a day of a non-commercial sunscreen formulation developed with the sun filters ethylhexyl methoxycinnamate, ethylhexyl salicylate, methyl anthranilate, and octocrylene dispersed in a base gel, with an estimated protection factor of 28.8. The pure base gel was used as a control. The samples were applied to an area delimited by a standard template (15 cm²) in an amount corresponding to 30 mg (2 mg cm²) for ten days. At two points in time, pre- and post-sample applications, the facial skin surface was swabbed to collect extracted DNA and processed to verify divergent degrees of 16 S RNA coding sequences. The data obtained allowed us to determine the abundance of different bacterial entities at the genus and species levels. The results showed that critical species of the acne process, such as Cutibacterium acnes and Staphylococcus epidermidis, seem to tolerate the evaluated formulation well and are not significantly affected by the formulation, suggesting no interference of its use concerning dysbiosis induction. These findings refute the idea that photoprotectors may cause skin dysbiosis in men.

Keywords: Cutibacterium acnes; Staphylococcus epidermidis; Acne vulgaris; Dysbiosis; Photoprotectors.