Gut and skin dysbiosis in acne vulgaris: a comparative microbiome analysis.

INTRODUCTION: Acne vulgaris (AV) is a chronic inflammatory skin disorder with multifactorial etiology involving host-microbiome interactions. While cutaneous dysbiosis has been extensively studied, the contribution of the gut microbiome and its potential interaction with the skin microbiome remains insufficiently characterized. METHODS: In this pilot study, paired facial skin swabs and stool samples were collected from 17 patients with moderate-to-severe AV and 14 healthy controls. Microbial DNA was extracted and the V3-V4 regions of the bacterial 16S rRNA gene were sequenced on the Illumina MiSeq platform. RESULTS: Acne patients exhibited significantly reduced gut microbial alpha diversity compared to controls (p < 0.001 across indices), accompanied by decreased diversity in the skin microbiome. Beta diversity analyses revealed distinct gut microbial community structures between groups, whereas skin microbial composition showed more subtle differences. Taxonomic profiling identified pronounced alterations in gut microbiota, contrasting with relatively modest shifts in skin communities. CONCLUSIONS: Our findings reveal a systemic pattern of microbial dysbiosis in AV, characterized by marked alterations in the gut microbiome alongside concurrent, albeit less pronounced, changes in the skin microbiome. These results support a role for the gut-skin axis in acne pathophysiology and highlight the need for integrative, system-level analyses of host-microbiome interactions in inflammatory skin diseases.