The role of skin microbial shifts in the pathogenesis of atopic dermatitis: a systematic review and meta-analysis

Abstract

Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by a disrupted skin barrier, immune dysregulation, and significant microbial dysbiosis. Increasing evidence suggests that shifts in the skin microbiome, notably involving key species such as Staphylococcus aureus and Staphylococcus epidermidis, play a pivotal role in AD pathogenesis. However, the extent and clinical implications of these microbial shifts remain unclear, necessitating a comprehensive synthesis of current evidence. This systematic review and meta-analysis aimed to synthesize current evidence on the shifts in skin microbiota associated with AD. Four databases, namely PubMed, Cochrane, Disbiome and Scopus were systematically searched from inception to May 2024, restricted to English-language publications. Randomized controlled trials, case-control, and cohort studies investigating microbial diversity and abundance in AD patients compared to healthy controls were included. Study quality was rigorously assessed using validated tools. Meta-analyses were conducted to quantify differences in microbial alpha diversity and S. aureus and S. epidermidis prevalence. From 608 initial records, 23 studies met the inclusion criteria, including 8 randomized controlled trials, 10 case-control studies, and 5 cohort studies. The meta-analysis demonstrated reduced alpha diversity in AD skin (SMD: -1.36, p < 0.00001) and increased S. aureus colonization (SMD: 3.49, p < 0.00001), particularly in lesional skin. S. epidermidis abundance was elevated overall, but it exhibited strain-dependent variability, with some strains exacerbating inflammation. Findings suggest microbial dysbiosis contributes to disease progression, supporting its relevance for clinical interventions. Microbiome-targeted therapies hold promise for integrated AD management, particularly by restoring microbial balance and strengthening the skin barrier.