Role of skin microbiome and exosomes in Hair regeneration and disorders in diseases like Alopecia, Acne: A comprehensive review

Hair disorders such as alopecia, acne, and seborrheic dermatitis affect millions worldwide, with significant psychosocial and clinical impact. Recent research highlights the importance of the skin microbiome and exosome-mediated cell communication in regulating hair follicle health, growth cycles, and immune balance. The skin microbiome forms a dynamic ecosystem that influences keratinocyte behavior, sebaceous activity, and local immune tone, while exosomes act as molecular couriers carrying growth factors, microRNAs, and cytokines that direct follicular regeneration and angiogenesis. Dysbiosis of the scalp microbiome can trigger inflammation, disrupt immune privilege, and contribute to hair loss, whereas targeted modulation of microbial diversity may restore homeostasis. Similarly, exosome-based therapies have shown potential to stimulate bulge stem cells, counteract follicular miniaturization, and promote hair regrowth. This review synthesizes current evidence on the microbiome–exosome crosstalk, explores its role in common follicular disorders, and discusses translational advances including microbiome restoration strategies, bioengineered exosomes, and combination therapies. Understanding these interconnected systems provides a foundation for precision scalp medicine and novel regenerative interventions.