Microscopic Colitis
Also known as: Collagenous colitis, Lymphocytic colitis
Microscopic colitis is a form of inflammation of the large intestine that causes persistent watery diarrhea, yet the bowel looks normal during a colonoscopy. The inflammation is visible only under a microscope, which is where the condition gets its name. There are two main types, collagenous colitis and lymphocytic colitis, which are treated in the same way. It mainly affects people over 50 and is more common in women, and it is often linked to autoimmune conditions, smoking, and certain medications. Although it can be exhausting and disruptive, microscopic colitis does not damage the bowel wall, does not raise the risk of colon cancer, and usually responds very well to treatment.
At a Glance
- Common symptoms
- Chronic watery, non-bloody diarrhea, often several times a day, Urgency and sometimes leakage of stool, including at night, Abdominal cramping or pain
- Main treatments
- Budesonide, a steroid that acts mainly in the gut with few body-wide effects, which is the most effective first-line treatment, Stopping or switching a suspected trigger medication, done in discussion with your prescriber, Antidiarrheal medication such as loperamide for milder symptoms or alongside other treatment
- Category
- Digestive · An increasingly recognized cause of chronic diarrhea in older adults, particularly women
- See a doctor if
- Watery diarrhea lasting more than four weeks
Symptoms
Causes
- An abnormal immune reaction in the lining of the colon, the exact trigger of which is unknown
- Medications including nonsteroidal anti-inflammatory drugs, proton pump inhibitors, some antidepressants (SSRIs), and statins in susceptible people
- Smoking, which is strongly linked to earlier onset
- An association with autoimmune conditions such as celiac disease, thyroid disease, and rheumatoid arthritis
- Possibly bile acid malabsorption or changes in gut bacteria following an infection
Risk Factors
- Age over 50
- Female sex
- Current or past smoking
- Autoimmune disease, especially celiac disease
- Regular use of NSAIDs, proton pump inhibitors, or SSRIs
Diagnosis
- A history of chronic watery diarrhea with normal blood tests and stool tests for infection
- Colonoscopy, which typically looks normal
- Multiple biopsies from different parts of the colon examined under a microscope, which is essential for diagnosis
- Blood tests for celiac disease and thyroid function, since these commonly coexist
- Review of medications that may have triggered the condition
Treatment
- Budesonide, a steroid that acts mainly in the gut with few body-wide effects, which is the most effective first-line treatment
- Stopping or switching a suspected trigger medication, done in discussion with your prescriber
- Antidiarrheal medication such as loperamide for milder symptoms or alongside other treatment
- Bile acid binders (cholestyramine) if bile acid malabsorption contributes
- Immune-suppressing or biologic medications for the minority who do not respond to budesonide
- Supportive: stopping smoking, which can reduce flares
- Supportive: temporarily limiting caffeine, alcohol, lactose, and artificial sweeteners during flares, and treating any coexisting celiac disease with a gluten-free diet
Prevention
- Do not smoke
- Use NSAIDs sparingly, and review long-term proton pump inhibitor use with your doctor
- Stay well hydrated during flares
- Keep coexisting autoimmune conditions well managed
- Report persistent diarrhea early rather than living with it for months
When to See a Doctor
- Watery diarrhea lasting more than four weeks
- Diarrhea that wakes you at night or causes leakage
- Signs of dehydration such as dizziness, dark urine, or confusion
- Blood in the stool, fever, or significant weight loss, which suggest a different diagnosis
- Symptoms that return after stopping treatment
Frequently Asked Questions
Related Conditions
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