Collagenous Colitis

A subtype of microscopic colitis with a thickened collagen band.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 10, 2026

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Dahiliye (İç Hastalıkları) department. Book Appointment →

What is Collagenous Colitis?

Collagenous colitis is one of two main subtypes of microscopic colitis (the other being lymphocytic colitis); it is most commonly seen in middle-aged and older women (mean age 55-65, female:male ratio 4-9:1).

Although the cause is unknown, autoimmune mechanisms, drugs (NSAIDs, PPIs, SSRIs), bile acid malabsorption, smoking, and genetic predisposition (HLA association) play a role; a thick (>10 µm) subepithelial collagen band is typical on histology.

Diagnosis is made by colonoscopic biopsy from the right colon. Treatment options include budesonide, drug discontinuation, smoking cessation, antidiarrheal agents, and bismuth subsalicylate. Symptoms commonly recur after stopping treatment.

Symptoms

Chronic non-bloody watery diarrhea (4-9 stools/day)

Nocturnal diarrhea

Abdominal cramps

Mild weight loss

Fatigue

Fecal incontinence

Joint pain

Risk Factors

Female sex

Age >50

Autoimmune diseases (celiac, RA, thyroid)

Long-term NSAID use

PPI and SSRI use

Smoking

HLA-DQ2/DQ8 positivity

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

Watery diarrhea lasting more than 4 weeks
Nocturnal diarrhea
Diarrhea unresponsive to dietary measures
Severe weight loss
Fluid-electrolyte imbalance

Treatment Methods

Colonoscopy and right-colon biopsy

Discontinuation of triggering drugs

Smoking cessation

Budesonide 9 mg/day for 6-8 weeks

Loperamide for symptoms

Bismuth subsalicylate

Long-term low-dose maintenance

Which Department to Visit?

You can visit our Dahiliye (İç Hastalıkları) department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Dahiliye (İç Hastalıkları) Department

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.