Topical Probiotics in Dermatology: Microbiological Mechanisms, Delivery Platforms, and Therapeutic Perspectives

The skin microbiome plays a central role in maintaining cutaneous homeostasis, and its disruption has been implicated in a wide range of inflammatory and degenerative skin disorders. This review critically evaluates the current evidence on topical probiotics in dermatology, integrating microbiological mechanisms, formulation strategies, and translational and regulatory challenges within a single framework—an angle that remains insufficiently addressed in previous reviews. A targeted search of PubMed and ScienceDirect (2009–2025) was conducted to identify relevant original studies. The results suggest that topical probiotics may promote skin health through three broad, interconnected axes: (i) modulation of host responses (e.g., inflammation, immune signaling, and oxidative stress); (ii) microbial ecology and pathogen control (e.g., competition, acidification, and antimicrobial metabolite production); and (iii) support of barrier function and tissue repair (e.g., lipid metabolism, re-epithelialization, and extracellular matrix remodeling). Efficacy appears to depend strongly on strain specificity, formulation design, and microbial viability during storage and application. In additio