In April 2020, the Food and Drug Administration (FDA) requested that all forms of prescription and over-the-counter (OTC) ranitidine (Zantac) be removed from the U.S. market. They made this recommendation because unacceptable levels of NDMA, a probable carcinogen (or cancer-causing chemical), were present in some ranitidine products. People taking prescription ranitidine should speak with their doctor about safe alternative options before stopping the drug. Individuals taking OTC ranitidine should stop taking the drug and talk with their healthcare provider about alternative options. Instead of taking unused ranitidine products to a drug take-back site, a person should dispose of them according to the product’s instructions or by following the FDA’s guidance.

Collagenous colitis refers to a type of microscopic colitis that characterized by a thick band of collagen under the lining of the colon. Symptoms of this condition include intermittent diarrhea, abdominal cramping, and pain.

This article explores the symptoms, causes, and treatment of collagenous colitis.

Share on Pinterest
Michela Ravasio/Stocksy

Collagenous colitis is a type of microscopic colitis where a thick, nonelastic band of collagen develops under the lining of the colon. Collagen is a type of structural protein in the body.

Scientists describe collagenous colitis as a type of microscopic colitis because the inflammation it causes is only noticeable under a microscope. Unlike most inflammatory bowel conditions, doctors do not consider the condition is a risk factor for colon cancer.

The term microscopic colitis usually refers to both collagenous colitis and lymphocytic colitis. Both conditions share the same signs, symptoms, diagnostic tests, and treatments.

Some research also shows that collagenous colitis and lymphocytic colitis may be different stages of the same condition.

Collagenous colitis is a rare disorder, with the highest incidence in adults over 50 years of age.

Only about 42 out of every 100,000 people receive a diagnosis of collagenous colitis.

The severity, frequency, and duration of collagenous colitis symptoms vary. People with this condition can experience flare-ups of frequent symptoms in between periods of remission with few or no symptoms.

While some individuals may have painful, disabling symptoms, others only experience mild discomfort. And though many experience flare-ups that last a few days or weeks, others may have symptoms lasting months or years.

Common symptoms of collagenous colitis include:

Collagenous colitis affects the colon, which is the large intestine. The colon takes a liquid mixture of digested food from the small intestine and turns it into a solid stool before delivering it to the rectum for removal from the body.

Collagenous colitis causes general inflammation of the epithelium, the base layer of cells that line the colon.

Colon epithelial cells are vital to the organ’s overall performance because they help digestion and maintain the relationship between the body’s immune system and the healthy communities of microbes in the gut.

When colon epithelial cells become damaged, a variety of digestive symptoms occur. In cases of collagenous colitis, the layer of collagen — the connective tissue protein that helps support the epithelial cells — becomes thicker than expected.

Collagenous colitis is similar to many other inflammatory gastrointestinal conditions, and researchers are not sure why the condition occurs. Most research indicates it likely has a genetic basis and may have links with other autoimmune diseases.

Some of the proposed causes of collagenous colitis include:

Some of the medications that have common associations with the development of collagenous colitis include:

Risk factors

Although people of any age can develop collagenous colitis, factors that may increase the risk of the condition include:

  • Being over 50: An estimated 75% of cases develop in people 50 years of age or older, though reports state some children have developed the condition.
  • Being female: Women are more likely than men to develop collagenous colitis.
  • Smoking: People who continue to smoke increase the risk of the condition.
  • Some medications: Several gastrointestinal, digestive, sleep, and mood medications have links with collagenous colitis.
  • Having an autoimmune condition: A history of autoimmune disease, including diabetes, rheumatoid arthritis, and celiac disease, has associations with the condition.
  • Family history: People with a family history of autoimmune conditions or colitis are more likely to develop collagenous colitis.

A gastroenterologist — a doctor who specializes in digestive and gastrointestinal conditions — will usually diagnose and treat collagenous colitis. They may start by performing a physical exam. They will then ask questions about the person’s family and medical history, as well as lifestyle habits, eating patterns, whether they smoke or have smoked, and which medications they use.

To diagnose collagenous colitis, the specialist will need to take multiple biopsies from different sections of the person’s colon.

A colon biopsy requires either a colonoscopy or a sigmoidoscopy, which involves inserting an endoscope into the anus. An endoscope is a plastic tube with a tiny camera that enables the doctor to see inside the intestine.

A pathologist will then examine these tissue samples under a microscope.

Many doctors will use additional medical tests to rule out other inflammatory gastrointestinal conditions as part of the diagnostic process.

Additional tests include:

  • blood tests
  • stool tests
  • X-rays
  • CT scans
  • MRIs

In most cases, collagenous colitis responds well to treatment. In some cases, the symptoms may even resolve without medical intervention.

In the first instance, doctors will advise a person to stop using any medication with links to collagenous colitis.

A variety of medications exist that can help reduce or resolve symptoms. Most studies suggest budesonide is an effective first line of therapy for collagenous colitis.

Other common prescription medications to help treat collagenous colitis include:

If symptoms do not improve, doctors may prescribe immunomodulatory or anti-tumor necrosis factor therapies, which block part of the immune response.

Making lifestyle changes can also usually help reduce symptoms. These include:

In rare cases, where severe symptoms do not respond to other forms of treatment, a doctor may recommend surgery to treat collagenous colitis.

Although each case of collagenous colitis varies, experts believe certain foods and chemicals increase the severity of symptoms and even spark flare-ups.

Although there is much conflicting information about what a person with collagenous colitis should and should not eat, the following dietary changes may help with easing symptoms and reducing the risk of complications:

  • avoiding caffeine and artificial sugars
  • avoiding dairy products if the person is lactose intolerant
  • avoiding foods containing gluten

It is also essential to drink plenty of liquids, and this is particularly important when someone has diarrhea.

People with collagenous colitis should speak with a doctor or dietitian to find the best approach for their condition.

Collagenous colitis is a type of microscopic colitis that causes periods of watery, non-bloody diarrhea that can last for days or months.

It is different from other forms of inflammatory bowel disease because the colon appears as expected on a colonoscopy and only shows signs of inflammation under the microscope. The condition occurs when a thick layer of collagen presents under the colon lining.

Symptoms are usually intermittent, meaning most people experience flare-ups for some time in between periods without symptoms.

Collagenous colitis symptoms can be uncomfortable and may lead to dehydration and malnutrition. However, people can manage symptoms with medications and diet adjustments.

Unlike other types of inflammatory gastrointestinal conditions, doctors do not believe collagenous colitis increases the risk of colon cancer.