Collagenous colitis and lymphocytic colitis

Collagenous colitis and lymphocytic colitis are types of inflammatory bowel disease (IBD) that involve inflammation of the colon, the last portion of the bowel that ends at the anus. They are sometimes collectively called ‘microscopic colitis’, since diagnosis of both conditions requires the examination of colon tissue under a microscope.

Lymphocytic colitis is so similar to collagenous colitis that some researchers believe them to be different stages of the same condition. However, this theory is unproven.

The most common symptom of both collagenous colitis and lymphocytic colitis is chronic non-bloody diarrhoea. Neither condition is contagious. They are not related to Crohn’s disease or ulcerative colitis, which are other types of IBD. There is no cure, but lifestyle changes and medical treatment can manage the symptoms in most cases.

Symptoms of collagenous colitis and lymphocytic colitis

Symptoms and signs may include:

• watery diarrhoea that does not contain blood or pus
• the diarrhoea may be chronic, or may come and go
• bowel incontinence
• abdominal cramps
• nausea
• abdominal bloating and discomfort
• fatigue.

Complications of collagenous colitis and lymphocytic colitis

Without treatment, complications may include:

• dehydration
• malabsorption of food nutrients
• malnutrition
• weight loss.

Collagenous colitis affects the collagen layer

The inner surface of the colon is lined with epithelial cells and is called the epithelium. The epithelium absorbs water from faeces. When a person has collagenous colitis, the epithelium is not inflamed or damaged, which is why the diarrhoea doesn’t contain blood or pus.

Beneath the epithelium is a layer of tough connective tissue made up of collagen, a type of protein that gives strength to many structures, including tendons, bones and skin. Collagenous colitis gets its name because the inflammation takes place within the collagen layer of the colon, which becomes thickened.

Lymphocytic colitis involves a build-up of immune cells

While lymphocytic colitis causes identical symptoms to collagenous colitis, the condition does not involve the collagen layer. Lymphocytic colitis gets its name from the characteristic build-up of immune system cells called lymphocytes within the colon’s epithelium.

Like collagenous colitis, the outer lining of the colon (epithelium) is undamaged, so there is no blood or pus in the diarrhoea.

Causes of collagenous colitis and lymphocytic colitis

Doctors aren’t sure what causes the inflammation. Theories include:

• infection with an unknown virus or bacterium
• problems with the immune system such as an autoimmune disorder, which means the immune system attacks a healthy part of the body by mistake. Some affected people may have autoimmune disorders such as rheumatoid arthritis, scleroderma or Sjogren’s disease
• certain medications that may increase the risk, including non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin.

Diagnosis of collagenous colitis and lymphocytic colitis

Most people are diagnosed between the ages of 60 and 80. The symptoms of collagenous colitis and lymphocytic colitis are similar to other gastrointestinal illnesses such as irritable bowel syndrome, Crohn’s disease and ulcerative colitis.

Diagnosis may include:

• medical history
• physical examination
• tests (such as a stool culture) to rule out other gastrointestinal diseases
• colonoscopy, the use of a slender viewing tube inserted into the colon via the anus to view the entire length of the colon. The lining of the colon should appear normal
• flexible sigmoidoscopy, the use of a viewing tube inserted through the anus to view the rectum. The lining of the rectum should appear normal
• biopsy, the removal of a small tag of tissue for examination in a laboratory, is essential for diagnosis. Changes, including an abnormally thick collagen layer or a build-up of lymphocytes, are visible under the microscope. Multiple biopsies must be taken.

Treatment of collagenous colitis and lymphocytic colitis

There is no cure, but treatment can manage the symptoms. Treatment options depend on the severity of the symptoms, but may include:

• Watchful waiting – some patients with mild symptoms improve without any treatment, for reasons unknown.
• Dietary changes – some foods and drinks aggravate diarrhoea. Your doctor may advise you to cut down on fatty or spicy foods, milk products, alcohol, sugary drinks and caffeine. Avoid gas-promoting products such as beans, cabbage and fizzy drinks. Opt for soft and easy to digest foods such as bananas and rice. Eat frequent small meals throughout the day, rather than three large meals.
• Switching medicines – some evidence suggests that non-steroidal anti-inflammatory drugs, including aspirin and ibuprofen, can worsen symptoms. Your doctor may recommend that you try different medicines, if possible, to see if symptoms improve.
• Anti-diarrhoea medication – this slows the passage of faeces through the colon.
• Other medications – if the above measures don’t seem to help, your doctor may suggest stronger medications such as corticosteroids to help ease the symptoms. Non-absorbable steroids (budesonide) often help. Medications containing 5-aminosalicylic acid (5ASAs) may also help.
• Surgery would rarely be necessary.

No link to colon cancer

Collagenous colitis and lymphocytic colitis are not related to cancer of the colon. There is no evidence to suggest that having either condition increases the risk of developing cancer of the colon.

Where to get help

• Your GP (doctor)
• Gastroenterologist
• The Gut Foundation Tel. (02) 9267 9421
• NURSE-ON-CALL Tel. 1300 606 024 – for expert health information and advice (24 hours, 7 days)