Background: Food allergy is a heterogeneous pediatric disease involving IgE-mediated, non-IgE-mediated, and mixed immune mechanisms, with manifestations ranging from mild symptoms to life-threatening anaphylaxis. Current diagnostic tools, including clinical history, skin prick testing, serum-specific IgE measurement, and oral food challenge, have limitations in specificity, invasiveness, prognostic value, and ability to guide personalized management. Methods: This narrative review summarizes emerging biomarkers in pediatric food allergy and evaluates their diagnostic, prognostic, predictive, and therapeutic potential. A literature search was conducted in PubMed/MEDLINE and Cochrane Central for English-language studies published between December 2015 and March 2026. Eligible studies included original clinical or translational research involving children aged 0–18 years and assessing functional cellular assays, epithelial barrier markers, intestinal permeability, gut microbiota, metabolomics, transcriptomics, proteomics, epigenetics, and immune biomarkers. Findings were synthesized qualitatively according to biomarker category and biological function. Results: Functional cellular biomarkers, particularly the basophil activation test, show the greatest translational readiness, with high diagnostic specificity, utility in reaction threshold and severity assessment, and potential value for monitoring oral immunotherapy. Biomarkers of epithelial barrier dysfunction, including zonulin, tight junction proteins, epithelial injury markers, filaggrin variants, and epithelial-derived cytokines, provide mechanistic insight into allergic sensitization and gastrointestinal phenotypes but remain insufficiently validated. Microbiota-derived, metabolomic, transcriptomic, proteomic, epigenetic, and integrated multi-omics approaches offer promising tools for risk prediction, tolerance monitoring, endotype identification, and precision medicine. Conclusions: Emerging biomarkers may improve diagnosis, risk stratification, therapeutic monitoring, and personalized care in pediatric food allergy. However, standardized assays, large longitudinal pediatric studies, and external validation are required before routine clinical implementation.

Background: Appropriate diagnostic testing is essential to quality pediatric allergy care, affecting diagnostic accuracy, treatment decisions, resource use, and patient outcomes. This study aimed to develop evidence-based recommendations for specialist consultations and diagnostic investigations in children with food allergies, eosinophilic gastrointestinal diseases, urticaria, angioedema, and atopic dermatitis. Methods: A multidisciplinary panel convened for the Italian National Institute of Health formulated and prioritized clinical questions using the PICO framework and structured expert consensus. A systematic review of the literature from 2015 to 2026 informed the recommendations, with certainty of evidence assessed using GRADE methodology. Results: In food allergy, sensitization tests alone are insufficient for diagnosis, while oral food challenges remain central to diagnostic confirmation. Endoscopic biopsies are essential for diagnosing eosinophilic gastrointestinal diseases. In chronic urticaria, specialist consultation is recommended, whereas routine allergy testing should be avoided without a suggestive clinical history. In angioedema, distinguishing histaminergic from bradykinin-mediated forms is critical, with targeted laboratory testing for hereditary or acquired conditions. In atopic dermatitis, standardized severity assessment should guide management and consideration of biologic therapies, while patient and family education represent key components of care. Conclusions: These recommendations provide a framework for standardized pediatric allergy diagnostic pathways, aiming to improve quality and equity of care while reducing unnecessary investigations and optimizing healthcare resource use.