The Role of the Microbiome in Lichen Sclerosus: Pathophysiological Insights and Therapeutic Implications

Lichen sclerosus (LS) is a chronic inflammatory and fibrotic dermatosis of unclear etiology, traditionally considered an autoimmune disorder. Emerging evidence suggests that microbiome dysbiosis may contribute to disease pathogenesis by modulating local immune responses and tissue remodeling. This narrative review synthesizes current data on the skin, genital, and gut microbiome in LS, focusing on potential mechanistic links between microbial imbalance and immune activation. Available studies consistently show alterations in microbial composition; however, findings remain heterogeneous because of the small sample sizes, methodological variability, and predominantly cross-sectional designs. Despite these limitations, accumulating data indicate that microbial dysbiosis may influence key immunological pathways involved in LS, including T-cell activation and chronic inflammation. In particular, mucosa-associated invariant T (MAIT) cells are proposed as a potential mechanistic bridge between microbial-derived signals and immune dysregulation, although their role in LS remains unclear. These observations support a conceptual model of LS as a microbiome-modulated inflammatory and fibrotic disorder rather than a purely autoimmune condition. Clinically, microbiome profiling and targeted modulation may offer novel diagnostic and therapeutic opportunities. Future research should prioritize longitudinal and interventional studies, ideally incorporating multi-omics approaches, to clarify causality and facilitate translation into clinical practice.