Symptoms and causes


Signs and symptoms of microscopic colitis include:

  • Chronic watery diarrhea
  • Abdominal pain or cramps
  • Weight loss
  • Nausea
  • 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

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)
  • Flutamide
  • 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.