Microbial dysbiosis in hidradenitis suppurativa

Introduction: Hidradenitis suppurativa (HS) is a chronic, relapsing inflammatory dermatosis primarily affecting pilosebaceous units in intertriginous regions. The disease exerts a substantial negative impact on patients’ quality of life. Accumulating evidence suggests that dysbiosis of the skin and gut microbiota, as well as the formation of microbial biofilms, play pivotal roles in sustaining chronic inflammation and driving lesion recurrence, although the underlying mechanisms remain incompletely elucidated. This review aims to synthesize current knowledge on the composition and functional implications of the microbiota and biofilm in HS, and to examine their contributions to disease pathogenesis. Methods: A systematic evaluation of studies investigating microbial composition in HS was conducted, encompassing both culture- -dependent and high-throughput sequencing methodologies. Both clinically affected and unaffected skin regions from diverse anatomical sites were included. Analyses focused on microbial profiles, compositional shifts, and the presence of biofilm structures to characterize the microbiological landscape associated with HS lesions. Results: Hidradenitis suppurativa lesions exhibit pronounced colonization by anaerobic bacteria ( Prevotella , Porphyromonas , Peptoniphilus ) alongside reduced abundance of pilosebaceous commensals ( Cutibacterium acnes , Staphylococcus epidermidis ). Dysbiotic patterns are also detectable in clinically unaffected skin, indicating a potential initiating role in disease pathogenesis. Biofilm formation is implicated in reduced responsiveness to antimicrobial therapies. Microbiota composition varies according to lesion depth, anatomical location, and disease stage, with host-related factors further influencing microbial community structure. Conclusions: Hidradenitis suppurativa represents a multifactorial dermatosis wherein microbial dysbiosis and biofilm formation perpetuate chronic inflammation and lesion recurrence. Anatomically targeted, longitudinal investigations of the microbiome, integrated with immunological profiling, are warranted. Such integrative studies may inform the development of personalized therapeutic strategies combining microbiota modulation, anti-biofilm interventions, and immunomodulatory therapies, thereby optimizing clinical management of HS.