The expanding spectrum of eosinophilic gastrointestinal disorders: summarizing diagnostic challenges, updated consensus diagnostic criteria, molecular drivers and site-specific histopathological changes

Aim: Eosinophilic gastrointestinal disorders (EGIDs) are chronic inflammatory conditions defined by eosinophilic infiltration of the gastrointestinal tract in the absence of secondary causes. This study aimed to synthesize current evidence on the clinical spectrum, pathogenesis, diagnostic criteria, and prognostic implications of EGIDs, including eosinophilic esophagitis, gastritis, duodenitis, ileitis, and colitis. Methods: A retrospective, multi-source observational analysis of published clinical datasets on EGIDs was conducted. Systematic searches of PubMed, Scopus, Web of Science, and EMBASE identified eligible studies that included ≥ 10 patients with EGIDs and provided quantitative data on eosinophil counts, clinical features, endoscopic and histopathological findings. Articles reporting secondary causes of eosinophilia were excluded. Data extraction was done and independently verified by two reviewers. Special emphasis was placed on unresolved diagnostic hurdles, pediatric versus adult presentations, and long-term disease implications. Results: A total of eligible datasets highlighted common molecular drivers, including epithelial barrier dysfunction, Th2-skewed immune responses, and genetic susceptibilities (e.g., TSLP, CAPN14). Core symptoms varied by site, with dysphagia predominating in eosinophilic esophagitis, and abdominal pain and diarrhea more frequent in distal EGIDs. Endoscopic findings included rings, furrows, and nodularity, while histology demonstrated patchy eosinophilic infiltration and epithelial damage with site-specific thresholds. Laboratory abnormalities included elevated eosinophil counts, IgE, and biochemical markers of malabsorption. Prognosis was variable, with frequent recurrence and heterogeneity in treatment response. Conclusions: Significant knowledge gaps persist in EGID research and practice. Priority areas include establishing consensus-driven histological thresholds and developing non-invasive biomarkers for disease monitoring. Urgent unresolved questions involve the utility of biomarkers in guiding therapy, monitoring response and systematic evaluation of pediatric versus adult differences. Addressing these gaps will require multidisciplinary collaboration, standardized diagnostic protocols, and longitudinal multicenter studies to improve both clinical care and research consistency.