New Normal Mask-Wearing and its Impact on Underneath Skin Microbiome: a cross-sectional study in acne vulgaris patients

Frequent and prolonged mask-wearing could contribute to changes of the skin microenvironment resulting in several facial dermatoses. Microbial dysbiosis has been proposed to link with these changes; however, data regarding the association between masks and skin microbiome is still limited. This cross-sectional study was conducted to explore the impact of face masks on the composition and diversity of skin bacterial microbiota. Participants were divided into short (less than 4 h/day) and long (at least 4 h/day) mask-wearing time (SMWT and LMWT) groups according to average time of wearing mask per day in previous 2 weeks. We swabbed the samples from cheek and forehead, representing mask-covered area (MCA) and mask-uncovered area (MUA), respectively, then stored, extracted and sequenced all specimens by targeting V3-V4 regions of 16S rRNA gene. QIIME2 was used to characterize bacterial communities. There were 45 mild acne vulgaris participants recruited with 12 (26.7%) and 33 (73.3%) participants in SMWT and LMWT groups, respectively. Based on multiple diversity metrics, there were no significant differences in beta-diversity across MCA/MUA or LMWT/SMWT groups. In alpha-diversity, the evenness on MCA was significantly lower in LMWT group compared to SMWT group (corrected P-value=0.049). Among all groups, the relative abundance of bacterial taxa was similar, showing Actinobacteriota and Firmicutes, and Cutibacterium and Staphylococcus as the most predominant phyla and genera, respectively. Our results showed no significant impact of mask wearing on the composition and diversity of skin microbiota in acne participants. However, this study could serve as a preliminary information for future research to explore the association between mask-related dermatoses and facial microbiome.