2026 Volume 40 Issue 3 Pages 151-158
The human skin sustains a complex ecological environment composed of diverse physical and chemical factors, where microbial communities, referred to as the skin microbiota, interact closely with the host. This review outlines how the skin environment shapes microbial composition, emphasizing the roles of lipid availability, moisture, pH, and oxygen tension in determining site-specific microbial communities. We further discuss alterations in the skin microbiota in various skin diseases, including atopic dermatitis, acne, psoriasis, and chronic wounds, from the perspectives of host immunity, microbial metabolism, and quorum sensing. In particular, the Agr quorum sensing system of Staphylococcus aureus and lipid metabolism by Cutibacterium acnes are highlighted as key mechanisms driving inflammation. Rather than being a simple consequence of disease, changes in the skin microbiota should be understood as part of a bidirectional interaction with the host environment. Future integrative approaches incorporating functional analyses will be essential to advance our understanding of skin diseases and to develop microbiota-targeted therapeutic strategies.
