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Collagenous Colitis- Causes, Symptoms, Diagnosis, and Management

Published on Dec 23, 2022   -  4 min read


Collagenous colitis is an inflammatory disorder of the small and large intestines. Colitis could be due to microbes, indigestion, and other unknown factors. Read below to know more.


Collagenous colitis is also known as diarrheal disease. It can occur in the small or large intestine. It can sometimes develop into ulcerative lesions with inflammation. Globally, enterocolitis cases are distributed at different proportions in different places. Almost half the disease pediatric population dies due to this condition annually. Another triggering factor for this condition is frequent international travel.

What Is Collagenous Colitis?

This condition occurs anywhere in the body, from the gastrointestinal tract to the rectal region. It can sometimes develop into ulcerative lesions with inflammation. It is an inflammatory condition of the small intestine followed by diarrhea. They are also known as idiopathic inflammatory diseases. Such colon inflammation could be due to microbial invasion, genetic predisposition, or other immunological responses caused due to changed gut flora. Activating inflammatory cells like neutrophils can damage the tissue wall and cause injury. The collective response gives rise to diarrhea and other functional abnormalities of the colon.

What Are the Different Types of Diarrhea?

Diarrhea is a medical condition where stool is excreted in large quantities, with loose consistency and frequent stool dissemination. An average human stool weighs around 250 gms. Out of which 70 % to 95 % is water content. During severe diarrhea, about 14 liters of water is lost. Depending on such factors, diarrhea is classified into five types:

  • Secretory Diarrhea: It has intestinal-rich plasma, which is isotonic fluid. This is mainly caused by Rotavirus, Escherichia coli, Clostridium perfringens, and excessive use of laxatives.

  • Osmotic Diarrhea: This is caused by over-exertion on the luminal wall causing high osmotic pressure. The causative agents are antacids, lactulose therapy, and gut lavages.

  • Exudative Disease: This is followed by heavy and frequent passing of stool. The stool is filled with bloody discharge. It is caused by Shigella spp, Salmonella spp, and Campylobacter spp.

  • Malabsorption: It is caused by indigestion. The stool is bulky but rich in osmolarity. This is mainly caused due to malabsorption of food, especially fatty substances (steatorrhea), and infections caused by Giardia lamblia.

  • Deranged Motility: Irregular stool output, volume, and consistency are followed by irregular stool output. The main causative factors are neural dysfunction, reduced gut length, hyperthyroidism, intestinal loop, and bacterial growth in the intestines.

What Are the Symptoms of Colitis?

Diarrheal disease like colitis is followed by symptoms such as.

  • Abdominal pain.

  • Discomfort in the anal region.

  • Diarrhea.

  • Fatigue.

  • Bloody stool or dysentery.

  • Lack of control over urination and stool passing (incontinence).

  • Low-volume stool.

  • Dehydration.

  • Bloating.

How Do Genetics, Immune Response, and Microbial Factors Play a Role in Collagenous Colitis?

Factors triggering inflammation of the colon could be due to dynamic reasons. Most of the etiology is still unknown. However, some of the pathogenesis are

  • Genetics: Studies have been conducted at the genetic level to study gene variations. Certain chromosomal variations are noted concerning chromosomes 3, 7, 12, and 16 causing bowel disease.

  • Immune Response: An imbalanced immune regulation can lead to bowel inflammation. As a result of the immune response, there are elevated levels of T and B cells in the gut mucosa, which is another contributing factor to inflammation.

  • Microbial Factors: Microbial infection or bacterial proliferation in the gut can lead to idiopathic inflammatory bowel disease.

Who Is at Risk of Developing Collagenous Colitis?

Some risk factors are associated with collagenous colitis as this is a multifactorial disease, such as

  • Diabetic patients.

  • Autoimmune disease.

  • Women are more affected than men.

  • People who have high cholesterol levels.

  • Smokers.

  • Medications like non-steroidal anti-inflammatory drugs (NSAIDs), selective serotonin reuptake, proton pump, and statins.

  • Patients on painkillers.

  • Thyroid disease.

  • Celiac disease.

  • Irritable bowel syndrome.

  • The rate of occurrence is higher in the older population, around fifty to sixty years.

What Are the Diagnostic Tests for Collagenous Colitis?

Tests to check for colitis condition are.

  • Blood Tests: Blood tests are not as revealing to confirm the diagnosis. Usually, patients may show a high erythrocyte sedimentation rate, autoantibodies, mild anemic conditions, and inflammatory factors in the blood.

  • Stool Tests: A high protein concentration exists in the stool. Other toxins include Clostridium difficile, Escherichia coli, and the presence of other parasites.

  • Colonoscopy: This is done to visualize the colon. It usually appears normal on colonoscopy.

  • Endoscopy Test: This standard test to check for collagenous colitis. An endoscopy of the lower gastrointestinal system is done. A colonoscope is inserted into the gut to visualize the colon up to the rectum. The physician advises the patient to stop any blood thinners intake one week before the test. This prevents excessive bleeding. The test is conducted while the patient is on a fast for at least eight hours. A laxative is given to clean up the bowel before conducting the test. The image is captured in the monitor, and further analysis is made.

  • Biopsy: A tissue sample is collected and studied under the microscope to confirm the diagnosis. The sub-epithelial fibrous bands more than ten millimeters in size are seen.

How Can We Treat Collagenous Colitis?

Treatment includes stopping any factor which can trigger or worsen the condition. Certain drugs and habits like smoking are highly associated with collagenous colitis. Some of the best treatment plans are.

  • Cessation of smoking.

  • Stopping harmful medications which can harm the mucosa, like non-steroidal anti-inflammatory drugs.

  • Administration of Budesonide (steroid) for severe diarrhea for six to eight weeks. If the symptoms persist, Cholestyramine is given four times a day until the symptoms stop.

  • Bismuth subsalicylate can be given if diarrhea does not stop even after two weeks, as the physician prescribes.

  • Not all patients respond positively toward treatment. Further surgery is recommended in severe conditions with an underlying cause of necrosis or tumor. Surgical procedures like ileotomy and subtotal colectomy are done.

  • Management of diet should be taken care of. Avoid foods like dairy products and fatty substances, which can promote defecation. Reduce caffeine and alcohol intake.


The primary cause of chronic diarrhea in patients is collagenous colitis. The increased bowel movements are responsible for frequent watery stool discharge, which is non-bloody. The patient is extremely tired, and immediate care must be given. A very less percentage of collagenous colitis is associated with colorectal cancer. Hence, the prognosis is good enough to get it treated. This can develop gradually or immediately with episodes of stool discharge more than thrice daily for four or more weeks.


Last reviewed at:
23 Dec 2022  -  4 min read




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