Collagenous or Microscopic Colitis

Collagenous or microscopic colitis is diagnosed and treated by the GI Division of Premier Medical Group.

What is collagenous colitis?

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Collagenous is an inflammation of the bowel that is only visible using a microscope (microscopic colitis). It is a rare digestive disorder that affects the colon and rectum, predominantly affects females, and presents most often in people over 45. Collagenous is a type of IBD, or inflammatory bowel disease, which occurs when there is an excessive build-up of white blood cells in the bowel lining causing inflammation in the bowel.

This type of colitis is less severe than other types of IBD because it does not lead to cancer and seldom requires surgery. However, microscopic colitis can cause substantial pain and discomfort. Microscopic colitis affects the colon and rectum.

What are the causes of collagenous colitis?

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The exact causes of collagenous colitis are unknown, but scientific evidence suggests immunological, environmental, and genetic factors as potential causes of the disorder. Some researchers believe collagenous colitis is a kind of autoimmune response, prompted by something in the GI tract. The immune system can react to harmless bacteria, pollen, food or even your own body’s cells. When the GI tract is kept empty for a period of time, the inflammation seems to subside, but when food is re-introduced and digestive activity occurs, the inflammation returns. To arrange this would require a surgical procedure called an ileostomy, which diverts digestive waste through an opening in the stomach.

Other theories for the cause(s) of collagenous colitis are:

  • Medications, such as aspirin, non-steroidal anti-inflammatory drugs, ranitidine, Zoloft, and Ticlid
  • Certain foods
  • Harmful and harmless bacteria (Yersinia enterocolitica, Campylobacter jejuni, and Clostridium difficile) that produce toxins that irritate the lining of the colon.
  • Viruses that trigger inflammation
  • Immune system problems such as autoimmune disorders (celiac disease, rheumatoid arthritis, and scleroderma)

What are the symptoms of collagenous colitis?

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The main symptom of collagenous colitis is chronic watery and non-bloody diarrhea, which can last for weeks, months, or even years. There can be a break in the episodes of diarrhea. It is believed that this type of diarrhea is brought on by the inability of the intestinal tract to absorb electrolytes (salts and minerals). This causes an imbalance and decreases the colon’s ability to absorb fluid, thus resulting in diarrhea.

Other common symptoms of microscopic colitis include:

  • Bloating and swelling of abdomen
  • Abdominal pain or cramps
  • Weight loss
  • Fatigue
  • Nausea
  • Fecal incontinence
  • Dehydration

How is microscopic colitis diagnosed?

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The only way to get an accurate microscopic colitis diagnosis is by examining intestinal tissue removed during colonoscopy or flexible sigmoidoscopy. Your doctor will also take a complete physical and medical history to be certain there are no other conditions present that could be causing the diarrhea. He or she will also ask you to provide a stool specimen to check for blood and/or infection. A blood test helps diagnose microscopic colitis by eliminating any other possible infections.

During the colonoscopy, your doctor will be able to rule out any other conditions by looking at the colon. Again, to be certain of a microscopic colitis diagnosis, the doctor will need to remove small pieces of tissue and send to the lab for testing. This is called a biopsy, and a pathologist (a doctor trained to diagnose diseases based on tissue appearance) examines the tissue with a microscope.


What are the types of microscopic colitis?

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There are two types of microscopic colitis: collagenous colitis and lymphocytic colitis. With collagenous, the layer of collagen beneath the epithelium appears thicker than normal, which may result from inflammation. In both types, there is an increase in white blood cells in the intestinal lining. The symptoms and treatment for lymphocytic and collagenous colitis are identical.

What are the treatment guidelines for microscopic colitis?

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The treatment for microscopic colitis begins with the alleviation of certain medications and foods. Antidiarrheal medications may be effective for some patients.

Your doctor may recommend:

  • Anti-diarrhea drugs
  • Drugs that block bile acids
  • Steroid medications to block inflammation
  • Drugs that suppress the immune system
  • Diet and medication changes to relieve diarrhea
  • Eating a low-fat, low-fiber diet
  • Avoiding (NSAID)  over-the-counter pain relievers
  • Using anti-inflammatory drugs
  • Surgery to remove all or a portion of your colon (when colitis symptoms are so severe that medications and diet are not helping)

What is the best diet for microscopic colitis?

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While many people find relief from the symptoms of microscopic colitis by stopping certain medications and/or taking different medications that target the colitis. For chronic problems and to prevent future symptoms, there are also plenty of dietary changes you can explore.

The best diet for microscopic colitis can mean different things to different people. Many of these changes can provide some measure of relief; some may not make any difference for you. Ideally, you won’t to adopt every single recommendation to alleviate the symptoms of microscopic colitis.

  • Eat many small meals instead of 3 large ones. This helps regulate digestion.
  • Eat foods that are easy to digest such as bananas, rice, and applesauce.
  • Avoid spicy, fatty and fried foods.
  • Avoid foods high in fiber.
  • Some people add turmeric spice to their diet. The curcumin in the turmeric has anti-inflammatory properties.
  • Drink plenty of fluids. Water is best, but fluids with added sodium and potassium (electrolytes) may be beneficial as well
    • Avoid liquids high in sugar and caffeine
    • Avoid alcohol
    • Consider watering down your fruit juice.
    • Consider eliminating dairy products. Many people substitute coconut milk.
    • Consider eliminating gluten.

Helpful tips

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There are lifestyle changes you can make, such as:

  • Eat many small meals instead of 3 large ones. This helps regulate digestion
  • Avoid spicy, fatty and fried foods
  • Drink plenty of fluids. Water is best, but fluids with added sodium and potassium (electrolytes) may be beneficial as well
    • Avoid liquids high in sugar, and caffeine
    • Avoid alcohol
    • Watering down your fruit juice is helpful
  • Eat foods that are easy to digest such as bananas, rice, and applesauce. Avoid foods high in fiber

For More Information

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Crohn’s & Colitis Foundation of America

386 Park Avenue South, 17th floor
New York, NY 10016–8804
Phone: 1–800–932–2423 or 212–685–3440
Fax: 212–779–4098

Digestive Disease National Coalition

507 Capitol Court NE, Suite 200
Washington, DC 20002
Phone: 202–544–7497
Fax: 202–546–7105

Gastro-Intestinal Research Foundation

70 East Lake Street, Suite 1015
Chicago, IL 60601–5907
Phone: 312–332–1350
Fax: 312–332–4757