Microscopic Colitis - Causes, Symptoms and Treatment


Microscopic Colitis is one of the lesser known inflammatory bowel diseases. It affects the large bowel which is the last part of the bowel made up of the colon and the rectum. It is called microscopic because changes to the bowel cannot be seen with the naked eye but only when a sample of tissue is looked at under a microscope.

Microscopic Colitis - Woman with Microscope

There are two different types:

  • Microscopic Collangenous Colitis (the layer of collagen, a type of protein in the intestine tissue, builds up and becomes thicker than normal)
  • Microscopic Lymphocytic Colitis (the thickness of the intestine tissue is normal but there are much higher levels than normal of lymphocytes)

Some doctors and scientists believe that these different types could just be different stages of the disease, although they are often found in the same person at the same time.

As these two different types have the same symptoms and treatment they are usually lumped together under the same name of microscopic colitis.

You may be reading this page because you have been given a diagnosis and want more information or because you have chronic diarrhea and are looking for answers.

DiarrheaNurse.com is always looking to provide answers for people who are suffering with this horrible symptom. Please read on to find out the answer to the question ' what is microscopic colitis ?' and find out more about this not very well known disorder.

What Causes Microscopic Colitis?

Unfortunately at present the cause is unknown but there are several theories. Some of these ideas are listed below and one of them may be correct or there could be a combination of reasons.

  • Use of certain medications (most commonly, triclopidine, ranitidine, arcabose, lansoprazole, sertraline and non-steroidal anti-inflammatory drugs like ibuprofen, aspirin and naproxen)
  • Autoimmune disease (It is known that people with this disorder are also more likely to suffer from other autoimmune problems like rheumatoid arthritis, celiac disease, psoriasis, thyroid conditions)
  • Genetic causes; although a responsible gene has not yet been found
  • Infections (some people develop Microscopic Colitis following bacterial or viral infections of the intestinal tract)
  • Malabsorption of bile acid (bile which is released by the liver to break down fat should be reabsorbed higher up in the intestines, if it reaches the large intestine it can cause diarrhea)

How Likely am I to Get It?

It is estimated that about 2 per 10,000 people in the US have microscopic colitis but the exact number is not known. It it also thought that 20-30% of cases of chronic diarrhea have this cause. These factors will make you more at risk:

  • Being of North European descent
  • Being female
  • Smoking
  • Over 50
  • Taking the implicated medications
  • Having an autoimmune disease

Microscopic Colitis Symptoms to Look Out For

The main symptom is chronic diarrhea which is watery, usually comes on suddenly and can be explosive. You will not see any blood which is common in other inflammatory bowel diseases.

One of the characteristics of this disorder is that you can be diarrhea free for a period of time and then you will have what is termed a 'flare up'. This could last for days, weeks or even months. It is possible to have as many as 20 episodes of diarrhea a day during a flare up. This will mean that you are at great risk of dehydration and in severe cases may need fluid replacement therapy in a hospital. Other symptoms you may have are:

  • Abdominal bloating
  • Mild abdominal pain
  • Nausea
  • Urgency (needing to go to the bathroom very quickly)
  • Fecal incontinence (accidentally passing poop)
  • Weight loss

It is quite common for this condition to be misdiagnosed as irritable bowel syndrome but one of the main differences is that with this disorder diarrhea and fecal incontinence often happens at night which is never the case with IBS.

How is it Diagnosed?

The only way to diagnose this form of colitis is to take a biopsy of the intestinal tissue and look at it under a microscope. If your symptoms are suggestive of microscopic colitis then you should be referred to a gastroenterologist who will have a look inside your colon with a colonoscopy which is a flexible tube with a light and a camera on the end.

If the lining of the bowel looks normal then this would rule out other inflammatory bowel diseases and the gastroenterologist may suspect microscopic colitis and should take several biopsies. More than one biopsy is needed as the disease is patchy.  

How is it Treated?

The good news is that some people recover spontaneously and no microscopic colitis treatment is required. Many people also find that their symptoms lessen over time and they can cope well by using anti-diarrheal medications such as loperamide hydrochloride (Imodium) occasionally.

If you are taking one or more of the implicated medications mentioned above then in consultation with your doctor these should be changed or the dosage reduced. Giving up smoking may also help.

There is no definite cure but if the symptoms do not become manageable or clear up completely with time as they do for many people then there are other microscopic colitis treatment options.

The steroid budesonide (Entocort) has been found to be effective and it has fewer side effects than other steroids.

Other medications which may help are antibiotics, anti-inflammatories and bile acid blockers.

For difficult cases that are not responding to treatment newer drugs can be tried such as:

  • Immunomodulators which weaken the immune system and try to prevent it overreacting; mercaptopurine (Purinethol); methotrexate (Rheumatrex and Trexall) and azathioprine (Azasan, Imuran)
  • anti-TNF medications which suppress the response to tumor necrosis factor which is involved in the inflammation process; adalimumab (Humira) and infliximab (Remicade) 

These drugs are only used in difficult cases as they carry risks with their side effects.

In very rare cases surgery is needed and a part of the colon may be removed but this is extremely unlikely.

Will it Help if I Alter My Diet?

There is no specific recommended microscopic colitis diet but some people find that their diarrhea is worse if they eat certain foods. Some people react to caffeine and artificial sweeteners, others to spicy or fatty foods and others to dairy products.

You should keep a food diary and see if your diarrhea is worse when you eat or drink certain things. Do not cut out whole food groups however as this could be dangerous and always see a doctor or dietitian before making radical changes to your diet.

It is very important to drink plenty of fluids to prevent dehydration when you have a flare up.

Can Microscopic Colitis Develop into Something Worse?

There have been a few cases where people seem to have gone on to develop Crohn's Disease or Ulcerative Colitis but a link was not conclusively proven. The chances of this happening are very low.

There is no evidence that people with this disorder are more at risk of colon cancer.

What is the Outlook?

In most cases the outlook is very good. Most people go on to make a full recovery or to have mild symptoms which are managed with medication.

Chronic diarrhea is a very difficult and life disrupting thing to live with. DiarrheaNurse.com hopes that you find some answers to your problem. It is important to see a doctor and have some tests done to discover exactly what is going on, as there are many different things that can cause this distressing symptom not just microscopic colitis.

Please look at our other pages about Chronic Diarrhea and 8 Common Chronic Diarrhea Causes.

For more information about other inflammatory bowel diseases please see the information below.

21 Ulcerative Colitis Symptoms

You are plagued with gut symptoms; is it ulcerative colitis?

Go to 21 Ulcerative Colitis Symptoms

Crohn's Disease Symptoms - Could This Be Your Problem?

Are you exhausted in pain and have to keep running to the bathroom? It could be Crohn's.

Go to Crohn's Disease Symptoms - Could This Be Your Problem?

Inflammatory Bowel Disease - Risk Factors and Symptoms

Get an overview here of the different diseases that cause inflammation of the bowel and other symptoms.

Go to Inflammatory Bowel Disease - Risk Factors and Symptoms

Return to Inflammatory Bowel Disease from Microscopic Colitis


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