The gut-skin axis: Investigating gut microbiota
dysbiosis in pemphigus and bullous pemphigoid

Gut microbiota dysbiosis has been linked with numerous autoimmune disorders and inflammatory skin pathologies. The present study is a narrative review aiming to examine dysregulations in the gut microbiota of patients with pemphigus and bullous pemphigoid, exploring how these alterations may contribute to diseases’ development and/or progression. Significant alterations in the composition of intestinal microbiota were identified in patients with pemphigus and bullous pemphigoid: reduction in short-chain fatty acid-producing bacteria: Faecalibacterium prausnitzii, Lachnospiraceae and Coprococcus spp., which are known for their anti-inflammatory effects, and increased abundance of Escherichia coli, Shigella spp., Klebsiella spp., Bacteroides fragilis and Flavonifractor spp., which are recognized for their pro-inflammatory impact. The composition of gut microbiota might influence the pathogenesis of autoimmune bullous diseases. Modified levels of bacteria could become innovative biomarkers for the detection of high-risk individuals, monitoring disease progression and predicting response to treatment. Furthermore, regulating bacterial levels might have therapeutic effects in diminishing inflammation and disease advancement, potentially serving as future therapeutic strategies.