Gut microbiome‑based interventions for treatment of atopic dermatitis—a mini review

Abstract

The gut microbiome has emerged as a central regulator of immune homeostasis and skin health through the gut–skin axis, a communication network linking intestinal microbes with distant organs. In atopic dermatitis (AD), a chronic inflammatory skin disease affecting millions worldwide, accumulating evidence implicates gut dysbiosis in disease pathogenesis and severity. This mini-review provides a comprehensive and critical synthesis of current knowledge regarding the role of the gut microbiome in AD, with a focus on mechanistic pathways, clinical evidence for microbiome-targeted interventions, and future research priorities. A systematic literature search was conducted in PubMed, Web of Science, and Scopus for studies published between January 2016 and March 2025; 1,247 unique records were identified, and 69 studies met inclusion criteria. Key mechanisms by which gut microbial composition influences AD include the production of immunomodulatory metabolites such as short-chain fatty acids (SCFAs) and tryptophan derivatives, regulation of regulatory T cell (Treg) differentiation and Th1/Th2 balance, maintenance of intestinal and skin epithelial barrier integrity, and modulation of neuroimmune interactions underlying pruritus. Clinical studies of probiotics, prebiotics, synbiotics, postbiotics, dietary modifications, and fecal microbiota transplantation are reviewed with particular attention to study design, sample size, effect sizes, risk of bias, and reproducibility. High-quality randomized controlled trials support the adjunctive use of specific probiotic strains; notably Lacticaseibacillus rhamnosus GG (1 × 10^10 CFU/day) and Bifidobacterium bifidum, in pediatric AD, with modest but statistically significant improvements in SCORAD scores and quality of life. However, evidence for other strains and for prebiotics, synbiotics, and dietary interventions remains limited, heterogeneous, and often preliminary. Important knowledge gaps include optimal strain selection, dosing, treatment duration, long-term safety, and mechanistic biomarkers of response. The review concludes with expert recommendations for future research, emphasizing the need for well-powered, long-term randomized controlled trials with standardized outcomes, multi-omics integration, and personalized approaches based on age, genetics, and baseline microbial composition. While gut microbiome modulation is not yet ready to replace conventional AD therapies, it represents a promising complementary strategy that warrants continued rigorous investigation.