What is microscopic colitis?

Microscopic colitis is an inflammatory bowel disease in which the colon (the large intestine) becomes inflamed (swollen, irritated). There are two types of microscopic colitis, lymphocytic colitis and collagenous colitis:

  • Patients who have lymphocytic colitis have an increase in lymphocytes (white blood cells) in the epithelium (the lining of the colon).
  • In patients who have collagenous colitis, the layer of collagen (fibrous connective tissue) under the epithelium becomes thicker.

Women, people over the age of 50 and people who have an autoimmune disease (the immune system attacks the body) are more likely to have microscopic colitis.

What causes microscopic colitis?

Microscopic colitis may have several different causes, including the following:

  • Certain autoimmune diseases, including celiac disease, thyroid diseases, rheumatoid arthritis and psoriasis
  • Medications, including nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen and naproxen; antacid and heartburn drugs; antidepressants; and certain drugs for treatment of cancer or heart disease
  • Infections (caused by bacteria or viruses)
  • Genetics (heredity)
  • Smoking

What are the symptoms of microscopic colitis?

The main symptom of microscopic colitis is non-bloody diarrhea, which the patient may have for some time. Other symptoms include:

  • Always feeling like you need to have a bowel movement
  • Weight loss
  • Pain and cramping in the abdomen
  • Fecal incontinence (leaking stool, caused by inability to control bowel movements)
  • Nausea
  • Dehydration (extreme thirst)
  • Bile acid malabsorption. Bile is made and released by the liver and then sent through tube-like structures called bile ducts to the small intestine, where it helps the body break down and absorb food. In bile acid malabsorption, something, such as a stone, is blocking the flow of bile from the liver and gallbladder to the intestine.

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy