The follicular microbiome in hair-follicle-associated inflammatory diseases: A systematic review
June 2026
in “
Clinical and Experimental Dermatology
”
follicular microbiome hair follicles inflammatory diseases Cutibacterium Staphylococcus scarring alopecias seborrheic dermatitis dandruff acne androgenetic alopecia alopecia areata rosacea hidradenitis suppurativa Porphyromonas Prevotella hair follicle bacteria scalp inflammation hair loss bacterial imbalance skin conditions
TLDR Certain bacteria levels change in hair follicle diseases, but their role is unclear.
This systematic review analyzed the bacterial microbiome of hair follicles in inflammatory hair-follicle-associated diseases, including 55 studies with 1,811 patients from 19 countries. The review found that Cutibacterium and Staphylococcus frequently showed altered relative abundance across various conditions. Staphylococcus was notably increased in scarring alopecias, seborrheic dermatitis/dandruff, and acne, while Cutibacterium abundance was reduced in seborrheic dermatitis/dandruff but more prevalent in androgenetic alopecia. The findings were inconsistent for Cutibacterium in scarring alopecias and acne, and inconclusive for alopecia areata and rosacea. Hidradenitis suppurativa showed enrichment of anaerobic opportunists like Porphyromonas and Prevotella. Despite methodological differences, these genus-level shifts were recurrent, though their causal significance is unclear. The study calls for larger, standardized research with functional analyses to better understand the biological relevance and therapeutic potential.
