Vitiligo and the microbiome of the gut and skin: a systematic review

Vitiligo is a chronic autoimmune skin condition characterized by depigmentation due to the destruction of melanocytes. Recent research has identified potential links between vitiligo and alterations in both the gut and skin microbiomes. This systematic review aims to explore these microbiome changes and their potential role in the onset and progression of vitiligo. A comprehensive search of the PubMed, Medline (OVID), and Web of Science databases was conducted to identify studies examining the gut and/or skin microbiota in vitiligo patients. A total of six studies were included in the qualitative analysis. Data extracted included study type, patient demographics, microbiome sampling methods, bacterial diversity, and bacterial ratios. The studies were assessed using the Methodological Index for Non-Randomized Studies (MINORS) scale. The results revealed inconsistent findings regarding microbial diversity in vitiligo patients. Some studies observed decreased α-diversity in the gut microbiome, while others found an increase, particularly in patients with longer disease duration. An increased Firmicutes-to-Bacteroidetes ratio (higher levels of Firmicutes bacteria compared to Bacteroidetes) was noted in several studies, suggesting a dysbiotic gut microbiome. In the skin microbiome, similar trends of dysbiosis were observed, with alterations in bacterial diversity between lesional and non-lesional skin. The findings indicate that gut and skin microbiome changes may play a role in the pathogenesis of vitiligo. However, the data remain inconclusive due to variability in methodologies and sample sizes. Further research is needed to elucidate the clinical relevance of microbiome alterations in vitiligo, with a focus on controlling external factors such as diet and lifestyle.