Inflammatory bowel disease
Ruling out parasitic infections, lactose intolerance, small intestinal bacterial overgrowth, and coeliac disease is recommended before a diagnosis of irritable bowel syndrome is made. An upper endoscopy with small bowel biopsies is necessary to identify the presence of celiac disease. An ileocolonoscopy with biopsies is useful to exclude Crohn's disease and ulcerative colitis (Inflammatory bowel disease).