The Skin Microbiome: Its role in Health and Disease, including Dysbiosis leading to Dermatological Conditions and Engineered bacteria and Skincare solutions for Dermatological Application

The human skin microbiome plays a pivotal role in sustaining cutaneous health through barrier fortification, immunological modulation, and microbial equilibrium. This review consolidates existing insights into the diversity, spatial heterogeneity, and functional dynamics of skin-associated microbes, with particular emphasis on the manner in which intrinsic and extrinsic factors—including age, hygiene practices, ultraviolet radiation exposure, and dietary habits—modulate the microbial landscape. Illustrative case studies from Indian populations and site-specific microbial assessments further elucidate the impact of genetic background, lifestyle variables, and environmental context. Microbial dysbiosis has been implicated in a spectrum of dermatological disorders, including atopic dermatitis, acne vulgaris, psoriasis, and chronic wounds, wherein disturbances in microbial communities contribute to heightened inflammation and compromised epidermal integrity. Emerging therapeutic modalities that incorporate prebiotics, probiotics, postbiotics, and engineered bacterial strains offer compelling alternatives to conventional treatments. Notably, “triple biotic” formulations—which integrate all three biotic components—are garnering increased attention for their synergistic efficacy in restoring cutaneous microbial homeostasis. Despite these advancements, several critical limitations persist. The field currently lacks a sufficient volume of clinical trials to substantiate the long-term safety, therapeutic efficacy, and regulatory viability of engineered or synbiotic skin-based therapies. Furthermore, the absence of standardized methodologies, harmonized clinical endpoints, and comprehensive data-sharing protocols continues to obstruct the successful clinical translation of microbiome-based innovations into standard dermatological practice. By synthesizing foundational microbiome science with emerging clinical and bioengineering developments—including triple biotic strategies and microbial engineering—this review delineates both the therapeutic potential and current constraints of microbiome-directed interventions, and provides a prospective framework for their future application in dermatology.