Microscopic Colitis: Types, Causes, Symptoms, and Diet

microscopic colitisMicroscopic colitis is an inflammatory condition in the large intestine that can be painful and frustrating to live with. While there are different types, in most situations, microscopic colitis is not nearly as serious as other forms of inflammatory bowel disease.

Many people have heard of ulcerative colitis, but microscopic colitis is not related to this condition.


So, what is microscopic colitis?

It’s inflammation in the colon that is too small to see, so a doctor can only diagnose it after taking a sample of tissue and checking it under a microscope.

Since some of the symptoms are similar to other gastrointestinal problems like irritable bowel syndrome (IBS), it can be misdiagnosed. A proper diagnosis is crucial since treatment for microscopic colitis is different than IBS treatment.

Types of Microscopic Colitis

There are two microscopic colitis types that can cause unpleasant abdominal symptoms. They are referred to as lymphocytic colitis and collagenous colitis.

  • Lymphocytic colitis: This type of microscopic colitis causes inflammation in the large intestine that leads to episodes of watery diarrhea and stomach pain. Essentially, inflammatory cells from the immune system travel to the large intestine, where they create swelling and inflammation of tissues. This inflammation can prevent the large intestine from reabsorbing enough water, which then leads to diarrhea, pain, and other symptoms.
  • Collagenous colitis: This type of microscopic colitis involves the presence of a thick band called “collagen” that appears under the lining of the colon. Collagen is a structural protein in the body. Watery diarrhea, mucus in stool, and abdominal pain are the main symptoms of collagenous colitis. The condition can last for years or disappear with or without treatment. It’s not considered a risk factor for colon cancer.

There is some debate about whether lymphocytic colitis and collagenous colitis is the same illness but just presented in different ways.

What Are the Causes of Microscopic Colitis?

Medical experts don’t know exactly what causes microscopic colitis. Some theories include bacteria, toxins, viruses, and even immune system problems. One suspected cause is bile acid not being absorbed properly and irritating the lining of the colon.

When we talk about microscopic colitis causes, it’s important to mention medications. It’s believed that some medications can increase the risk of getting this condition. Researchers suspect that some drugs irritate the lining of the colon more than others. Anti-inflammatories, drugs for heartburn relief, and certain antidepressants are some examples.

We do know that microscopic colitis is more common in people aged 50 to 70, and that it’s more likely to happen to women than men. Here are a few other risk factors:

  • Autoimmune diseases
  • Genetic link
  • Smoking

Symptoms of Microscopic Colitis

Microscopic colitis symptoms can be frustrating to cope with. People who have been diagnosed with this disease are often afraid to leave home for fear of not being able to find a washroom since the main symptom is non-bloody diarrhea.

Here are the most common symptoms of microscopic colitis:

  • Constantly feeling the need to have a bowel movement
  • Abdominal pain and cramping
  • Weight loss
  • Leaking stool
  • Dehydration
  • Nausea
  • Bile acid malabsorption

Also Read : Incomplete bowel movement (Tenesmus): Causes, symptoms, treatment, and home remedies

Microscopic Colitis Diagnosis

To arrive at a microscopic colitis diagnosis, a number of steps have to take place. A gastroenterologist is a doctor who specializes in digestive diseases. He or she will begin by taking a full medical history and conducting a physical exam.

Medical tests to rule out other bowel diseases including IBS, Crohn’s disease, ulcerative colitis, and celiac disease may be carried out. This could involve lab tests, imaging tests, or an endoscopy of the intestines.

An important part of the diagnostic process is getting a biopsy, which means small pieces of tissue are taken for examination. A pathologist is a doctor who specializes in examining these tissues under a microscope.

To give you a better perspective, the following list covers most of the procedures used to diagnose microscopic colitis:

  • Medical and family history: This includes a review of eating habits, medications, other medical conditions, and family medical conditions.
  • Physical exam: An examination of the patient’s body that includes tapping on specific areas of the abdomen.
  • Lab tests: This may include blood tests and stool tests.
  • Imaging tests: Computerized tomography (CT) scans, magnetic resonance imaging (MRI), and upper GI series are imaging tests carried out by trained technicians. They can show physical abnormalities. CT scans use a combination of x-rays and computer technology to create images while an MRI is a close look at internal organs without using x-rays. Upper GI series is a type of x-ray exam that provides a view of the shape of the upper GI tract.
  • Endoscopy: This is a look at intestines that may include a colonoscopy with biopsy, flexible sigmoidoscopy with biopsy, or upper GI endoscopy with biopsy. A colonoscopy uses a long, flexible tube with a tiny light and camera on one end to look inside the rectum and colon. Light anesthesia is usually involved to help relax the patient. The camera sends a video image of the intestinal lining to a computer screen for a gastroenterologist to see. The doctor will decide during a colonoscopy whether or not to biopsy areas of the colon.

With a flexible sigmoidoscopy, a flexible narrow tube with a light and camera looks inside the rectum and sigmoid colon. This test doesn’t require anesthesia. In this case, the scope that’s used inflates the large intestine with air to give the gastroenterologist a better view. A biopsy can be taken with this procedure as well. An upper GI endoscopy uses a tube with a light and tiny camera too; however, it’s taking video images of the upper GI tract. The patient gargles with a liquid anesthetic to prepare the throat, as the endoscope is fed down the esophagus and into the stomach. A biopsy of the lining of the small intestine is retrieved for examination.

Treatment for Microscopic Colitis

Microscopic colitis treatment often depends on how severe the symptoms are. A doctor will take a patient’s lifestyle into account and review medications the person is taking before making any recommendations in terms of treatment for microscopic colitis. The patient may be told to change or stop a specific medication and the doctor will likely urge the individual to quit if they are a smoker.

Gastroenterologists can prescribe medications that can help control some of the symptoms that come with microscopic colitis. There are often recommendations to adjust diet. Unfortunately, there are cases where surgery may be required. This is usually when symptoms are severe and other treatments are not working. The doctor could suggest removing the colon; however, surgery is rare for microscopic colitis.

Diet for Microscopic Colitis

Microscopic colitis can sometimes get better without any special treatment, but in a lot of cases, dietary changes can make a significant difference. Research shows that certain ingredients irritate the colon so a microscopic colitis diet may help. Caffeine, artificial sweeteners, lactose, and gluten are examples of ingredients that are known to be irritating. Staying hydrated is also part of dietary recommendations for those who suffer from microscopic colitis. This is because diarrhea dehydrates the body. Beverages with electrolytes, broth, and diluted fruit juices can be consumed as well as water.

Here are some easy to digest foods that are good choices for people who suffer from microscopic colitis:

  • Applesauce
  • Bananas
  • Melons
  • Rice

Here are some foods and beverages that should be avoided:

  • Any foods or beverages that contain caffeine
  • Spicy foods
  • Foods that are high in fiber or lactose
  • Beans
  • Nuts
  • Raw vegetables
  • Dairy products
  • Foods with artificial sweeteners
  • Bread, pastas, and other starches
  • Fatty or fried foods
  • Alcohol
  • Soda

How you eat is also important when you suffer from microscopic colitis. Large meals can aggravate symptoms, while smaller meals may help reduce bouts of diarrhea, pain, and cramping. Some people also benefit from taking a daily probiotic. Additionally, a multivitamin and mineral-rich diet have proved to be helpful for many people with chronic diarrhea.


Pinpointing the cause of microscopic colitis is key because it allows for targeted treatment. For example, if you’re diagnosed with this condition and are told that it’s likely due to an autoimmune disease, treating this underlying disease may help get some of the symptoms under control.

If your doctor suggests dietary changes and you find this overwhelming, you should consider meeting with a dietician who can help you plan meals. It can also be helpful to keep a food diary to track what foods trigger your symptoms.

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Author Bio

Emily Lunardo studied medical sociology at York University with a strong focus on the social determinants of health and mental illness. She is a registered Zumba instructor, as well as a Canfit Pro trainer, who teaches fitness classes on a weekly basis. Emily practices healthy habits in her own life as well as helps others with their own personal health goals. Emily joined Bel Marra Health as a health writer in 2013.



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