Inflammatory Bowel Disease Differential Diagnoses

Updated: Apr 10, 2020
  • Author: William A Rowe, MD; Chief Editor: BS Anand, MD  more...
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Diagnostic Considerations

Approximately 90% of patients with Crohn disease have involvement of the terminal ileum and/or right colon. Pediatric patients are more likely (about 20%) to present with disease limited to the small intestine, although very young children often present with purely colonic disease. Occasionally, gastric or duodenal Crohn disease manifests as seemingly refractory peptic ulcer disease.

Consider anorexia and bulimia in patients with suspected inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), because not only are abdominal pain, weight loss, and vomiting consistent in these four conditions, but IBD is frequently diagnosed in late-teen and young-adult patients, which are also the peak years for anorexia and bulimia.

Due to the nonspecific gastrointestinal symptoms of Crohn disease and ulcerative colitis, several other diagnoses (see below) must be considered before establishing a diagnosis of Crohn disease or ulcerative colitis, particularly in the absence of typical endoscopic findings and in populations at higher risk for other diagnoses.

Note that historically—and especially when a preoperative computed tomography (CT) scanning has not been done—Crohn disease is frequently diagnosed at the time of laparotomy for presumed appendicitis. Another disease in the differential diagnosis is salmonellosis, which can present as bloody diarrhea.


Consider the following conditions in patients with diarrhea as a dominant symptom:

Abdominal pain, gastrointestinal bleeding, and/or intestinal ulceration

In patients with predominant abdominal pain, gastrointestinal bleeding, and/or intestinal ulceration, consider the following conditions in the differential diagnosis:

  • Ischemic colitis

  • Radiation-induced colitis

  • Arteriovenous malformations

  • Nonsteroidal anti-inflammatory drug (NSAID) enteropathy

  • Behcet disease

  • Intestinal tuberculosis

  • Colorectal malignancy

Differential Diagnoses