UC Davis

OBJECTIVE: This review examines the current literature on the gut-skin connection in alopecia and summarizes interventions that impact hair growth by modulation of the gut or skin microbiome. METHODS: PubMed searches were done to assess studies of the gut and skin microbiome and forms of alopecia including, alopecia areata (AA), androgenic alopecia (AGA), alopecia universalis (AU), central centrifugal cicatricial alopecia (CCCA) and lichen planopilaris (LPP). Filters were applied for human and animal studies. Articles not translated to English and studies assessing supplemental therapies on alopecia were excluded. RESULTS: There is evidence that scalp, hair follicle, and gut microbiome alterations are associated with various types of alopecia. There is potential in the use of interventions targeting microbiome dysbiosis, including fecal transplants and probiotics. LIMITATIONS: This field of study still requires more high-quality research and studies with larger participant populations. CONCLUSION: Dysbiosis on the scalp, within the hair follicle and the gut seem to have a role in the pathophysiology of various forms of alopecia. There is evidence that interventions targeting dysbiosis may have potential in the treatment and management of hair loss. Further studies are needed to establish a direct connection and to clarify specific effects of these interventions.