Microscopic colitis is colon inflammation that may give you chronic watery diarrhea. Changes to your diet, medications, or surgery might be possible treatments to consider.

Microscopic colitis is an inflammation of the colon. It leads to digestive symptoms, including chronic diarrhea. Treatment depends on symptoms and severity.

Sometimes, changes to diet and lifestyle are enough, but medication and surgery are possible treatment options to discuss with a healthcare team.

Microscopic colitis is a condition that affects your colon, also called your large intestine. It’s an inflammation, and it commonly causes persistent and watery diarrhea. Confirming a diagnosis of microscopic colitis requires examining colon tissue under a microscope. This is what gives the condition its name.

There are three subtypes of microscopic colitis:

  • Collagenous colitis: This type of microscopic colitis causes a layer of protein to develop in the colon tissue.
  • Lymphocytic colitis: This type of colitis causes an increase in white blood cells, called lymphocytes, in your colon.
  • Incomplete microscopic colitis: In this subtype, there are features of both collagenous and lymphatic colitis.

The word “colitis” means inflamed colon, and there are multiple similarities between ulcerative colitis (UC) and microscopic colitis.

But, they’re not the same condition. UC is a type of inflammatory bowel disease (IBD) and is the result of your immune system attacking tissue in the colon. While microscopic colitis also affects the colon, it’s not linked to IBD.

UC is typically diagnosed with a colonoscopy. Microscopic colitis can also be diagnosed with a colonoscopy.

Also, although both conditions often cause diarrhea as a symptom, UC is linked to bloody diarrhea. Microscopic colitis doesn’t typically cause blood in diarrhea.

The most common symptom of microscopic colitis is chronic diarrhea. Diarrhea can occur between 5 and 10 times a day and is typically watery. Additional symptoms can include:

Symptoms can come and go. People with microscopic colitis might have periods when symptoms are difficult to manage, followed by times they don’t experience symptoms. It’s also possible for symptoms to resolve on their own.

The exact cause of microscopic colitis is unknown, but researchers believe several factors could be linked to microscopic colitis. Some possible causes are:

Several risk factors have been linked to microscopic colitis. These include:

  • being between 50 and 70 years old
  • being a woman
  • having a family history of irritable bowel syndrome (IBS)
  • having certain autoimmune diseases, including type 1 diabetes, thyroid disease, rheumatoid arthritis, and celiac disease
  • smoking
  • taking certain medications, including some medications for pain, heart conditions, allergies, blood pressure, depression, and migraine.

Treatment of microscopic colitis depends on multiple factors, such as your specific symptoms and on their severity. Sometimes, changes to your diet and lifestyle can resolve symptoms. Other treatments can include medications and even surgery.

Common treatment options include

  • A low-fat high-fiber diet: A change of diet can help your digestive system and can resolve the symptoms of microscopic colitis.
  • Identifying foods that trigger symptoms: For some people, specific foods can make the symptoms of microscopic colitis worse. Finding those foods and eliminating them from your diet can make a big difference.
  • Quitting smoking: Quitting smoking can help improve your overall health and relieve some symptoms of microscopic colitis.
  • Changing medications: Medications can worsen, or even cause, microscopic colitis. Your doctor might change your medications if they suspect one of them is linked to your symptoms.
  • Bulking agents: A bulking agent is a medication that makes your bowel movements slower and more solid.
  • Antidiarrhea medications: An antidiarrhea medication shows down your muscle’s contractions, relieving some symptoms.
  • Bile-blocking medications: Bile blockers can help reduce inflammation and diarrhea.
  • Steroids: Steroids can bring down inflammation.
  • Anti-inflammatories: Medications targeted at the inflammation in your colon can sometimes help relieve symptoms.
  • Immune-suppressants: Immune-suppressant medications can be an option if your doctor believes that your immune system is causing the inflammation in your colon.
  • Surgery: Sometimes, surgery to remove part of the colon is the best way to treat severe microscopic colitis.

Microscopic colitis is a condition that leads to inflammation in your colon’s lining. The most common symptom of microscopic colitis is chronic, watery, diarrhea. The exact cause of microscopic colitis is unknown, but suspected causes include both viral and bacterial infections, as well as autoimmune conditions and genetics.

Treatment depends on symptoms but typically includes dietary changes and medications, with surgery as an option when symptoms are severe.