Diagnostic Complexity in Pediatric Chronic Colitis With Allergic, Infectious, Histamine-Related, and Oral-Phase Contributors: A Case Report With Long-Term Follow-Up.

Pediatric chronic colitis may present with overlapping gastrointestinal, allergic, dietary, and microbiome-related features, making early therapeutic decisions challenging, particularly when immunosuppression is being considered. This report describes an eight-year-old boy with chronic diarrhea and intermittent hematochezia beginning in early childhood, a history of cow's milk protein allergy, selective eating, poor mastication, inflammatory stool biomarkers, and colonoscopic findings consistent with mild chronic ileocolitis. Because the family declined systemic immunosuppression, a structured gut-focused approach was implemented over 18-24 months, including dietary elimination, reduction of dietary histamine burden, feeding therapy, digestive and diamine oxidase (DAO) support, microbiota modulation, and treatment of suspected enteric infections or overgrowth. Over time, the patient's stool normalized, bleeding resolved, inflammatory markers improved substantially, and repeat colonoscopy demonstrated mucosal healing. This case highlights the potential relevance of individualized, nonimmunosuppressive gastrointestinal strategies in selected pediatric patients with chronic Crohn-like colitis and allergic or histamine-related features, while recognizing that causality cannot be established from a single case.