Characterizing the Skin and Gut Microbiome of Alopecia Areata Patients

Background: Alopecia areata (AA) is caused by autoimmune attack of the hair follicle. The exact pathogenesis is unknown, but hypotheses include innate immunity imbalance, environmental exposures, genetic predisposition, and possibly the microbiome. The objective of this study was to characterize the skin and gut microbiome of AA patients, and compare microbial composition to healthy individuals. Methods: This was a pilot, case-control study. Scalp and fecal microbiome samples were collected from 25 AA patients, and 25 age, gender, and race-matched healthy controls in Southern California with no significant difference in demographic characteristics. After library preparation and identification of bacterial and fungal taxonomy, multivariant analysis was performed to compare AA and healthy microbiomes. Results: The AA scalp microbiome was significant for decreased Clostridia and Malasseziomycetes, and the gut microbiome was significant for decreased Bacteroidia and increased Bacilli (p<0.05) compared to healthy controls. Conclusions: The composition of the AA bacterial and fungal, scalp and gut microbiome is significantly different than healthy individuals. Future directions include using this data to characterize microbial changes associated with AA patient diet, relating to disease severity, and predicting disease progression, prognosis and/or therapeutic response.