Probiotic Modulation of the Skin Microbiome: Emerging Therapeutic Strategies in Dermatology

Abstract

The skin microbiome is a dynamic microbial ecosystem that plays a fundamental role in maintaining epidermal barrier integrity, regulating immune homeostasis, and protecting against pathogenic colonisation. Dysbiosis of the skin microbiota has been implicated in numerous dermatological disorders, including acne vulgaris, atopic dermatitis, psoriasis, rosacea, and premature skin ageing, highlighting the microbiome as an emerging therapeutic target. In this context, probiotics have attracted increasing attention as microbiome-based interventions owing to their ability to restore microbial equilibrium and modulate host-microbe interactions. This review critically evaluates the current understanding of probiotics in dermatology, with particular emphasis on the molecular mechanisms underlying their therapeutic effects. Recent studies demonstrate that probiotics exert strain-specific activities through competitive exclusion of pathogens, production of antimicrobial peptides and bioactive metabolites, modulation of Toll-like receptor (TLR)-mediated signalling, regulation of nuclear factor kappa B (NFκB) and mitogen-activated protein kinase (MAPK) pathways, enhancement of tight junction proteins and ceramide synthesis, and modulation of cytokine networks involved in cutaneous immunity. Representative probiotic strains, including Lacticaseibacillus rhamnosus GG, Lactobacillus acidophilus, Lactobacillus plantarum, Bifidobacterium species, Bacillus coagulans, Saccharomyces boulardii, and Enterococcus faecium, are discussed with respect to their strain-specific molecular effectors and dermatological applications. Clinical evidence supporting oral and topical probiotic interventions is critically appraised, highlighting both therapeutic potential and the heterogeneity of existing studies. Emerging advances in postbiotics, engineered probiotics, synthetic biology, CRISPR-based microbiome editing, multi-omics technologies, and artificial intelligence-driven precision microbiome medicine are also discussed as future directions. Despite encouraging findings, important challenges remain, including strain standardisation, formulation stability, regulatory harmonisation, and the need for robust multicentre clinical trials. Collectively, current evidence suggests that probiotics represent promising adjunctive strategies for microbiome-targeted dermatological therapy; however, further molecular and translational investigations are required to facilitate their integration into scientifically validated precision dermatology.