Microscopic Colitis (Collagenous and Lymphocytic Colitis) Differential Diagnoses

Updated: Mar 25, 2021
  • Author: Harika Balagoni, MD; Chief Editor: BS Anand, MD  more...
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Diagnostic Considerations

Rule out microscopic colitis (MC) in those who fulfill the criteria for functional bowel disease, especially in the presence of risk factors for microscopic colitis and/or in the absence of response to therapy for irritable bowel syndrome (IBS).

Microscopic colitis should be considered as a differential diagnosis in the workup of chronic diarrhea, especially in the elderly population. In addition, microscopic colitis should be considered in patients diagnosed with celiac disease who have diarrhea that fails to respond to a gluten-free diet. 

Differential diagnosis

Different small bowel diseases and conditions may mimic microscopic colitis, including the following:

  • Concurrent lymphocytic colitis (LC) and lymphocytic gastritis [31]

  • Celiac disease: Collagenous colitis (CC) may represent a diffuse manifestation of gluten sensitivity; therefore, it is reasonable to evaluate patients for celiac disease [32]

  • Infectious colitis (other than Clostridium difficile infection)

  • Ischemic colitis

  • Laxative abuse

  • Bile acid malabsorption

Important considerations

Patients whose condition fails to respond to reasonable medical therapy should be evaluated for other conditions that may clinically mimic lymphocytic colitis and collagenous colitis.

The adverse effects of corticosteroids and immunosuppressants/immunomodulators may be serious. Such drugs would be difficult to justify in a patient later found to have an irritable bowel syndrome (IBS) or infectious or other causes of colitis or enteritis that should have been treated differently.

Performing a colonoscopy on patients with chronic diarrhea is commonly accepted and widely practiced, but performing biopsies in all such individuals has a low yield, even with normal findings on endoscopy. Patients clinically assessed as having diarrhea-predominant IBS (IBS-D) in whom conventional medical therapy is refractory may in fact have microscopic colitis, and these patients may benefit from colonoscopy with biopsies.

Limit biopsies to those subgroups of patients in whom microscopic colitis is most likely, such as patients with watery, severe, debilitating, or nocturnal diarrhea; substantial weight loss; an elevated erythrocyte sedimentation rate; or patients who are immunosuppressed.

Special concerns

As with the management of inflammatory bowel disease (IBD), antidiarrheal and nonimmunosuppressive medications have an acceptable risk in pregnant patients when clinical symptoms are significant and might threaten the pregnancy.

Methotrexate may induce spontaneous abortion and is contraindicated during pregnancy. 6-Mercaptopurine and azathioprine may cause fetal harm but so may refractory colitis. Consequently, the risk versus benefit considerations must be carefully discussed before prescribing these medications to a pregnant patient.

Differential Diagnoses