Microscopic Colitis (Collagenous and Lymphocytic Colitis) Guidelines

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

Statements and recommendations on the management of microscopic colitis (MC) were released by United European Gastroenterology (UEG) and the European Microscopic Colitis Group (EMCG) in August 2020. [10]

The two main MC histologic subtypes are collagenous colitis (CC) and lymphocytic colitis (LC); however, incomplete forms exist (incomplete MC [MCi]).

Pathogenesis and Risk Factors

The pathogenesis of MC is complex and multifactorial, potentially including luminal factors, immune dysregulation, and genetic predisposition. Risk factors include the following:

  • Former and, particularly, current smoking is associated with an increased risk of CC and LC. Insufficient evidence exists to assess the influence of smoking cessation on the disease course.

  • Women have a higher risk of developing CC or LC than men.

  • Chronic or frequent use of proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs (NSAIDs), or selective serotonin reuptake inhibitors (SSRIs) is associated with a greater risk of MC, but a causal relationship is not implied.

  • AGA suggests considering withdrawing drugs that are suspected of having a chronologic relationship between the introduction of the agent(s) and the diarrheal onset.

  • MC does not raise the risk of colorectal cancer or adenoma. A special surveillance colonoscopy program is not recommended.

Clinical Manifestations

The most common MC symptom is chronic watery, non-bloody diarrhea that is often associated with other symptoms, including fecal urgency/incontinence, and nocturnal stools.

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

Patients with MC have impaired health-related quality of life, depending on the activity, disease severity, and associated comorbidities.


Although endoscopic findings are increasingly recognized in patients with MC, they are nonspecific.

For CC, the histopathologic criteria (on hematoxylin–eosin [H&E]-stained slides) are a thickened subepithelial collagenous band of 10 µm or greater, combined with an increased inflammatory infiltrate in the lamina propria.

For LC, the histopathologic criteria (on H&E-stained slides) are an increased number of intraepithelial lymphocytes (IELs) of at least 20 per 100 surface epithelial cells combined with an increased inflammatory infiltrate in the lamina propria and a not significantly thickened collagenous band (< 10 µm).

Incomplete MC comprises incomplete CC (defined by a thickened subepithelial collagenous band >5 µm but < 10 µm) and incomplete LC (defined by >10 IELs but < 20 IELs and a normal collagenous band). Both types show a mild inflammatory infiltrate in the lamina propria. These criteria apply to H&E-stained slides.


UEG/EMCG recommend the following for treatment:

  • For induction of remission in CC or LC: Oral budesonide

  • Oral budesonide is effective for maintaining remission in patients with CC and LC

  • Other potential treatment options would be, mesalamine or bismuth salicylate or oral prednisone or prednisolone

  • For MC and bile acid diarrhea, suggested treatment is with bile acid binders

  • Consider treatment with thiopurines, anti-tumor necrosis factor (anti-TNF) drugs, or vedolizumab in patients with MC whose condition fails to respond to budesonide to induce and maintain clinical remission

  • Consider surgery as the last option in selected patients with MC if all medical therapies fail