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 part of the bowel that ends at the anus. They are sometimes grouped together as ‘microscopic colitis’, because diagnosing both conditions requires examining colon tissue under a microscope.

Lymphocytic colitis is so similar to collagenous colitis that some researchers believe the two may be different stages of the same condition. This idea, however, remains unproven.

There is no cure for either condition, but lifestyle changes and medical treatment can manage the symptoms in most cases. The most common symptom is chronic, watery diarrhea that does not contain blood or pus.

How the colon is affected#

The inner surface of the colon is lined with epithelial cells, a layer known as the epithelium. The epithelium absorbs water from the feces.

In collagenous colitis, the epithelium itself is not inflamed or damaged, which is why the diarrhea contains no blood or pus. Beneath the epithelium lies a layer of tough connective tissue made of collagen, a protein that gives strength to many structures in the body, including tendons, bones and skin. Collagenous colitis is named because the inflammation occurs within this collagen layer, which becomes thickened.

Lymphocytic colitis causes identical symptoms but does not involve the collagen layer. It is named for the build-up of immune system cells called lymphocytes within the colon’s epithelium. As with collagenous colitis, the epithelium stays undamaged, so there is no blood or pus in the diarrhea.

Symptoms#

• Watery diarrhea that does not contain blood or pus
• Diarrhea that may be ongoing, or may come and go
• Bowel incontinence
• Abdominal cramps
• Nausea
• Abdominal bloating and discomfort
• Fatigue

Possible complications#

Without treatment, complications may include:

• Dehydration
• Poor absorption of nutrients from food
• Malnutrition
• Weight loss

Causes#

Doctors are not certain what triggers the inflammation. Theories include:

• Infection with an as-yet unidentified virus or bacterium
• A problem with the immune system, such as an autoimmune disorder, in which the immune system mistakenly attacks a healthy part of the body. Some affected people have autoimmune conditions such as rheumatoid arthritis, scleroderma or Sjogren’s syndrome.
• Certain medications that may increase the risk, including non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin

Most people are diagnosed between the ages of 60 and 80.

Diagnosis#

The symptoms overlap with other gastrointestinal conditions such as irritable bowel syndrome, Crohn’s disease and ulcerative colitis. Diagnosis may include:

• Medical history and physical examination
• Tests, such as a stool culture, to rule out other gastrointestinal diseases
• Colonoscopy, in which a slender viewing tube is inserted through the anus to view the entire length of the colon. The lining of the colon usually appears normal.
• Flexible sigmoidoscopy, in which a viewing tube is inserted through the anus to view the rectum. The lining of the rectum usually appears normal.
• Biopsy, the removal of a small piece of tissue for laboratory examination, which is essential for diagnosis. Changes such as an abnormally thick collagen layer or a build-up of lymphocytes can be seen under the microscope. Several biopsies usually need to be taken.

Treatment#

There is no cure, but treatment can manage the symptoms. The options depend on how severe the symptoms are, and may include:

• Watchful waiting. Some people with mild symptoms improve without treatment, for reasons that are not fully understood.
• Dietary changes. Some foods and drinks can aggravate diarrhea. Your doctor may suggest cutting down on fatty or spicy foods, milk products, sugary drinks and caffeine, and avoiding gas-promoting foods such as beans, cabbage and fizzy drinks. Soft, easy-to-digest foods such as bananas and rice may help. Eating frequent small meals through the day, rather than three large ones, can also be easier to manage.
• Reviewing medications. Some evidence suggests that NSAIDs such as aspirin and ibuprofen can worsen symptoms. Where possible, your doctor may suggest trying different medicines to see if symptoms improve.
• Anti-diarrhea medication, which slows the passage of feces through the colon.
• Stronger medications. If the measures above do not help, your doctor may suggest corticosteroids to ease symptoms. Non-absorbable steroids (budesonide) often help. Medications containing 5-aminosalicylic acid (5-ASAs) may also help.

Surgery is only rarely needed.

No link to colon cancer#

There is no evidence that having either condition increases the risk of developing cancer of the colon. Neither condition is contagious, and they are not related to Crohn’s disease.

Key points#

• There is no cure, but lifestyle changes and medical treatment can manage the symptoms in most cases.
• Doctors are not sure what causes the inflammation.
• Diagnosis requires examining colon tissue under a microscope.
• Where possible, your doctor may suggest trying different medicines to see if symptoms improve.
• There is no evidence that either condition increases the risk of colon cancer.

Where to get help#