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 In this study, we explored the vulvar skin microbiota composition in VLS patients using 16S rRNA gene sequencing and evaluated the therapeutic potential of a postbiotic derived from Lactobacillus crispatus NCU-31. L. crispatus NCU-31 was isolated and its probiotic properties were confirmed in vitro . A postbiotic formulation was then developed and applied in combination with topical glucocorticoids in VLS patients. Clinical efficacy was assessed using the Investigator’s Global Assessment (IGA), Dermatology Life Quality Index (DLQI), and Vulvar Quality of Life Index (VQLI), alongside microbial profiling of the vulvar skin. Results VLS patients exhibited significantly increased microbial richness and diversity, characterized by reduced Lactobacillus abundance and elevated levels of Prevotella , Gardnerella , Dialister , and Streptococcus ( p  < 0.05). Combined postbiotic and glucocorticoid treatment led to significant clinical improvement, evidenced by decreased IGA scores and improved DLQI and VQLI ( p  < 0.05). Moreover, microbial dysbiosis was partially reversed, with an increase in Lactobacillus and reduction of pathogenic genera. Conclusions This study demonstrates that L. crispatus -derived postbiotics can enhance the efficacy of glucocorticoid therapy, alleviate clinical symptoms, and help restore microbial homeostasis in VLS patients. These findings provide a promising basis for the development of microbiota-targeted adjunctive therapies in the management of chronic vulvar inflammatory disorders. Clinical trial registration: http://www.chictr.org.cn/,identifier ( ChiCTR2400090750), registration time: 12/10/2024.