Microscopic colitis is an inflammation of the large intestine (colon) that causes persistent watery diarrhea. The disorder gets its name from the fact that it's necessary to examine colon tissue under a microscope to identify it, since the tissue may appear normal with colonoscopy or flexible sigmoidoscopy.
There are two subtypes of microscopic colitis:
- Collagenous colitis, in which a thick layer of protein (collagen) develops in colon tissue
- Lymphocytic colitis, in which white blood cells (lymphocytes) increase in colon tissue
Researchers believe collagenous (kuh-LAYJ-uh-nus) colitis and lymphocytic colitis may be different phases of the same condition. Symptoms, testing and treatment are the same for both subtypes.
The symptoms of microscopic colitis can come and go frequently. Sometimes the symptoms resolve on their own. If not, your doctor can suggest a number of effective medications.
Signs and symptoms of microscopic colitis include:
- Chronic watery diarrhea
- Abdominal pain or cramps
- Weight loss
- Fecal incontinence
When to see a doctor
If you have watery diarrhea that lasts more than a few days, contact your doctor so that your condition can be diagnosed and properly treated.
It's not clear what causes the inflammation of the colon found in microscopic colitis. Researchers believe that the causes may include:
- Medications that can irritate the lining of the colon.
- Bacteria that produce toxins that irritate the lining of the colon.
- Viruses that trigger inflammation.
- Autoimmune disease associated with microscopic colitis, such as rheumatoid arthritis or celiac disease. Autoimmune disease occurs when your body's immune system attacks healthy tissues.
- Bile acid not being properly absorbed and irritating the lining of the colon.
Risk factors for microscopic colitis include:
- Age and gender. Microscopic colitis is most common in people ages 50 to 70 and more common in women than men. Some researchers suggest an association with a decrease in hormones in women after menopause.
- Autoimmune disease. People with microscopic colitis sometimes also have an autoimmune disorder, such as celiac disease, thyroid disease, rheumatoid arthritis, type 1 diabetes or psoriasis.
- Genetic link. Research suggests that there may be a connection between microscopic colitis and a family history of irritable bowel syndrome.
- Smoking. Recent research studies have shown an association between tobacco smoking and microscopic colitis, especially in people ages 16 to 44.
Some research studies indicate that using certain medications may increase your risk of microscopic colitis. But not all studies agree. Medications that may be linked to the condition include:
- Aspirin, acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin IB, others)
- Proton pump inhibitors including lansoprazole (Prevacid), esomeprazole (Nexium), pantoprazole (Protonix), rabeprazole (Aciphex), omeprazole (Prilosec) and dexlansoprazole (Dexilant)
- Acarbose (Precose)
- Ranitidine (Zantac)
- Selective serotonin reuptake inhibitors (SSRIs) such as sertraline (Zoloft)
- Carbamazepine (Carbatrol, Tegretol)
- Clozapine (Clozaril, Fazaclo)
- Entacapone (Comtan)
- Paroxetine (Paxil, Pexeva)
- Simvastatin (Zocor)
Most people are successfully treated for microscopic colitis. The condition does not increase your risk of colon cancer.
Microscopic colitis care at Mayo Clinic
Jan. 05, 2018
- Feldman M, et al. Other diseases of the colon and rectum. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. http://www.clinicalkey.com. Accessed Jan.6, 2016.
- Microscopic colitis: Collagenous colitis and lymphocytic colitis. National Institute for Diabetes and Digestive and Kidney Diseases. http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/microscopic-colitis/Pages/facts.aspx. Accessed Jan.6, 2016.
- Dietrich CF. Lymphocytic and collagenous colitis (microscopic colitis): Clinical manifestations, diagnosis, and management. http://www.uptodate.com/home. Accessed Jan. 6, 2016.
- Pardi DS. Microscopic colitis. Clinics in Geriatric Medicine. 2014;30:5.
- Nguyen GC, et al. American Gastroenterological Association Institute guideline on the medical management of microscopic colitis. Gastroenterology. 2016;150:242.
- Münch A, et al. Microscopic colitis: Clinical and pathologic perspectives. Clinical Gastroenterology and Hepatology. 2015;13:228.
- Ohlsson B. New insights and challenges in microscopic colitis. Therapeutic Advances in Gastroenterology. 2015;8:37.
- Nutrition therapy for diarrhea. Nutrition Care Manual. Academy of Nutrition and Dietetics. https://www.nutritioncaremanual.org/client_ed.cfm?ncm_client_ed_id=20. Accessed Jan. 7, 2016.
- McNally PR. Colitis: Pseudomembranous, microscopic and radiation. In: GI/Liver Secrets Plus. 5th ed. Philadelphia, Pa.: Saunders Elsevier; 2015. https:// www.clinicalkey.com. Accessed Jan. 8, 2016.
- U.S. News best hospitals 2015-2016. U.S. News & World Report. http://health.usnews.com/best-hospitals/rankings/gastroenterology-and-gi-surgery. Accessed Dec. 27, 2015.
- Picco MF (expert opinion). Mayo Clinic, Jacksonville, Fla. Jan. 10, 2016.