The Gut–Skin Axis in Pediatric Atopic Dermatitis: Nutritional Modulation, Microbiome Interactions, and Emerging Precision Approaches

Background/Objectives: Pediatric atopic dermatitis (AD) is a barrier-driven inflammatory skin disease with systemic immune and microbial correlates. The gut–skin axis offers a biologically plausible framework through which early-life nutrition, gut microbial metabolism, intestinal barrier function, and immune maturation may influence disease risk and expression, but much of the supporting evidence remains associative. This narrative review asks which nutritional strategies are supported by clinical evidence in children with AD, which remain investigational, and how far the field is from precision nutrition. Methods: PubMed/MEDLINE, Scopus, and Web of Science were searched up to 31 July 2026; guidelines, systematic reviews, randomized trials, birth cohorts, and mechanistic studies with pediatric relevance were prioritized and appraised narratively. Results: Breastfeeding when possible, dietary diversity during complementary feeding, avoidance of unnecessary elimination diets, correction of documented nutritional deficiencies, and management of confirmed food allergy are supported by current guidance. Probiotics and synbiotics lower SCORAD in meta-analyses, but the pooled effect is small, heterogeneous, and below the minimal clinically important difference, so they are best described as an optional adjunct rather than a recommended treatment; Mediterranean-style or high-fiber dietary patterns are backed mainly by observational data. Microbiome profiling, metabolomics, multi-omics endotyping, and artificial intelligence remain research tools without validated predictive value for dietary responses. Conclusions: Nutrition is an adjunct to, not a substitute for, established topical and systemic therapy in pediatric AD. Precision nutrition is a promising research direction rather than an established component of routine care, and its clinical value will depend on standardized biomarkers and well-designed longitudinal and interventional studies.