Irritable Bowel Syndrome in Inflammatory Bowel Disease: An Evidence-Based Practical Review

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction characterized by recurrent abdominal pain associated with a change in the frequency and/or form of stools. Approximately one in three patients with quiescent inflammatory bowel disease (IBD), defined as the absence of endoscopic evidence of active inflammation, experience IBS-type symptoms. These symptoms are associated with reduced quality of life and increased psychological burden, and can complicate clinical assessment by mimicking conditions such as small intestinal bacterial overgrowth, bile acid malabsorption, or post-inflammatory complications. This up-to-date narrative review examines the mechanisms, diagnostic challenges, and management of IBS-type symptoms in quiescent IBD. Evidence suggests that these symptoms arise from a complex "matrimony" of functional and organic processes, including low-grade residual inflammation, altered intestinal permeability, microbiota dysbiosis, visceral hypersensitivity, and psychosocial impairment. Diagnosing IBS-type symptoms in IBD requires a "positive", symptom-focused approach while carefully excluding active inflammation. Management should adopt a biopsychosocial approach, integrating dietary strategies (e.g., low-FODMAP diet), brain-gut behavioral therapy, biofeedback therapy, and/or pharmacological treatments such as antispasmodics, antidiarrheals, laxatives, and neuromodulators to address both physiological and psychological factors. Future research should integrate sensitive biomarkers and longitudinal follow-up to enhance diagnostic precision and guide personalized therapy. Understanding and addressing the overlap between IBS and IBD is essential to reduce the multidimensional burden on physical health, psychological well-being, and daily functioning.