What is collagenous colitis?

Collagenous colitis is one of the two main types of microscopic colitis. Microscopic colitis is inflammation in the colon that is best identified by looking at colon cells under the microscope. The other type of microscopic colitis is lymphocytic colitis.

In collagenous colitis, a thick layer of collagen, which is a type of connective protein, forms within the colon tissue. The symptoms can disappear and reappear.

The symptoms of collagenous colitis can come and go, and vary in severity.

The most common symptoms include:

  • chronic watery diarrhea
  • abdominal pain
  • abdominal cramps

Other symptoms that can be less common include:

  • dehydration
  • weight loss
  • bloating
  • gas or flatulence
  • nausea
  • vomiting
  • fatigue
  • urgency to go to the bathroom
  • incontinence, which is the loss of bladder control

Collagenous colitis doesn’t cause blood in your stool or increase your risk for colon cancer. The diarrhea can appear and disappear over a period of weeks, months, or years.

Up to one-third of people with collagenous colitis may be misdiagnosed with irritable bowel syndrome (IBS) because many of the symptoms of the two conditions overlap.

Like many other gastrointestinal conditions, the exact cause of collagenous colitis is unknown. Research indicates that it likely has a genetic basis and could be related to other autoimmune conditions. Some possible causes of collagenous colitis include:

  • genetic abnormalities
  • certain bacteria or viruses
  • certain medications
  • autoimmune conditions like rheumatoid arthritis, psoriasis, and Crohn’s disease
  • smoking

Collagenous colitis isn’t contagious. It can’t spread to other people.

Collagenous colitis is more common among women than men. It’s also more common among people who are in their 50s.

In addition, women who have celiac disease are more likely to have collagenous colitis.

Collagenous colitis may also be more common among current smokers and people with a family history of the condition.

An estimated 4 to 13 percent of all chronic diarrhea cases involve microscopic colitis.

Researchers have noticed that the number of collagenous colitis cases is increasing. This may be because better detection is available.

This condition can only be diagnosed with a biopsy of the colon. You’ll likely also have a colonoscopy or sigmoidoscopy so that your doctor can better evaluate the health of your colon.

During a biopsy, a doctor removes several small pieces of tissue from your colon. Then the tissues are examined under a microscope.

The common diagnosis process includes:

Some of the tests and procedures are used to rule out other medical conditions that may cause similar symptoms.

In some cases, collagenous colitis disappears on its own without treatment. However, some people need treatment. Your treatment plan will depend on the severity of your symptoms.

Diet and lifestyle changes

Your doctor may recommend diet and lifestyle changes to help treat this condition. These changes are usually the first part of any treatment plan.

Common diet changes include:

  • switching to a reduced-fat diet
  • eliminating caffeine and lactose
  • avoiding food with artificial sweeteners
  • eating a gluten-free diet
  • drinking more fluids to prevent dehydration from diarrhea
  • switching to a milk-free diet

Common lifestyle changes include:

  • quitting smoking
  • maintaining a healthy weight
  • maintaining a healthy blood pressure
  • exercising regularly
  • staying hydrated


Your doctor will review the medications you currently take and make suggestions about either continuing or stopping them. In addition, your doctor may recommend new medications to help treat this condition.

Your doctor may also recommend that you take:

  • anti-diarrheal medications
  • intestinal anti-inflammatory medications, like mesalamine (Pentasa) or sulfasalazine (Azulfidine)
  • psyllium
  • corticosteroids
  • antibiotics
  • immunomodulators
  • anti-TNF therapies
  • medications that block bile acids


Your doctor may recommend surgery if diet and medication changes don’t help. Surgery is usually only used in extreme cases. It’s not a typical treatment for collagenous colitis.

The most common types of surgery for collagenous colitis include:

  • colectomy, which means removing all or part of the colon
  • ileostomy, which means creating an opening in the abdomen after a colectomy

Collagenous colitis can come and go, and relapses are common. You may need to try several treatments to find relief from the symptoms. The time it takes to recover can vary. Some people may have symptoms for weeks, months, or years.

There are no current recommendations for preventing collagenous colitis. However, following diet and medication changes recommended by your doctor may reduce the likelihood of having a relapse.

Collagenous colitis is a type of inflammatory bowel disease. It’s not contagious and can’t spread to other people. The only way to diagnose this inflammation is by examining colon tissue from a biopsy under a microscope.

The symptoms of this condition can come and go. The most common symptoms are watery diarrhea, abdominal pain, and cramps.

You may have relapses of collagenous colitis. Seek your doctor’s help on a treatment plan to avoid the chance of this happening.

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