Postbiotics originated from Lactobacillus crispatus NCU-31 improves vulvar lichen sclerosus: a randomized, double-blind controlled trial

BACKGROUND: Vulvar lichen sclerosus (VLS) is a chronic inflammatory skin disorder that severely impairs women’s physical and psychological well-being. Topical glucocorticoids are the first-line treatment; however, their long-term efficacy is limited due to frequent symptom relapse after discontinuation and incomplete resolution of lesions. Therefore, effective adjunctive strategies are urgently needed to achieve sustained disease control. METHODS: This study aimed to first characterize disease-associated alterations in vulvar skin microbiota by comparing patients with VLS and healthy volunteers using 16S rRNA gene sequencing. Based on these findings, we further evaluated the clinical efficacy of a postbiotic derived from Lactobacillus crispatus NCU-31 and its modulatory effects on vulvar skin microbiota in patients with VLS. Clinical efficacy was assessed using the Cattaneo Clinical Score and Investigator’s Global Assessment (IGA), Dermatology Life Quality Index (DLQI), and Vulvar Quality of Life Index (VQLI). RESULTS: Compared with healthy volunteers, VLS patients exhibited significantly increased microbial richness and diversity, characterized by a reduced relative abundance of Lactobacillus and elevated levels of Prevotella, Gardnerella, Dialister, and Streptococcus (p < 0.05). Compared with the placebo group, patients receiving combined postbiotic and glucocorticoid treatment showed significant clinical improvement, including lower IGA scores (0.38 ± 0.49 vs. 1.38 ± 0.49), improved DLQI (0.16 ± 0.37 vs. 3.86 ± 1.01), and improved VQLI (0.74 ± 0.66 vs. 6.36 ± 1.14) (p < 0.05). In addition, microbial dysbiosis was partially reversed in the postbiotic group, whereas no comparable microbiota normalization was observed in the placebo group. CONCLUSIONS: This two-phase study first included an exploratory comparison of vulvar skin microbiota between patients with VLS and healthy controls, which provided biological context for the subsequent clinical investigation. Building on these findings, we demonstrated that the addition of L. crispatus NCU-31–derived postbiotics to standard glucocorticoid therapy significantly improved clinical outcomes and partially restored microbial homeostasis in patients with VLS. These results support the potential of postbiotic-based, microbiota-targeted adjunctive strategies for the management of VLS. TRIAL REGISTRATION: http://www.chictr.org.cn/ , identifier (ChiCTR2400090750), registration time: 12/10/2024.