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Colitis is inflammation of the colon. Read about the different types and associated symptoms.

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Colitis is inflammation of the colon. Your colon is part of your large intestine. If you have colitis, it may also affect other parts of your intestines. You’ll feel discomfort and pain in your abdomen that may be mild and reoccurring over a long period of time, or severe and appearing suddenly.

Types of Colitis

The different types of colitis are categorized by what causes them.

Ulcerative Colitis (UC)

UC is one of two conditions classified as inflammatory bowel disease. The other is Crohn’s disease. UC is a long-lasting disease that produces inflammation and bleeding ulcers within the inner lining of your large intestine. It generally begins in your rectum and spreads to the colon. UC is the most commonly diagnosed type of colitis. It occurs when your immune system overreacts to bacteria in your digestive tract, but experts don’t know why this happens. Common types of UC include:

  • proctosigmoiditis, which affects the rectum and lower portion of the colon
  • left-sided colitis, which affects the left side of the colon beginning at the rectum
  • total colitis, which affects the entire large intestine

Pseudomembranous Colitis (PC)

This type of colitis occurs from overgrowth of the bacterium Clostridium difficile. This kind of bacteria normally live in your intestine but don’t cause problems because they’re balanced by the presence of other, “good” bacteria. If you take certain medications (especially antibiotics), it may destroy healthy bacteria and allow Clostridium difficile to take over. The bacteria release toxins that cause inflammation.

Ischemic Colitis (IC)

Ischemic colitis occurs when blood flow to your colon is suddenly cut off or restricted. Blood clots are the most common reason for sudden blockage. Atherosclerosis, or the buildup of fatty deposits, in the blood vessels that supply your colon is usually the reason for recurrent IC. This type of colitis is sometimes the result of underlying conditions. These may include:

  • vasculitis (inflammatory disease of the blood vessels)
  • hernia
  • diabetes
  • colon cancer
  • dehydration

Although it’s rare, IC may occur as a side effect of taking certain medications.

Additional Causes

Other causes of colitis include infection from parasites, viruses, and food poisoning from bacteria. You may also develop the condition if your large intestine has been treated with radiation.

Who Is at Risk for Colitis?

Different risk factors are associated with each type of colitis.

You’re more at risk for UC if you fall into one of these categories:

  • You are between the ages of 15 and 30 (most common) or 60 and 80.
  • You are of Jewish or Caucasian descent.
  • You have a family member with UC. This type tends to run in families. According to the National Institute of Diabetes and Digestive and Kidney Diseases, some research has shown that certain abnormal genes are often present in those with UC.

You’re more at risk for PC if you:

  • are taking long-term antibiotics
  • are hospitalized
  • are receiving chemotherapy
  • are taking immunosuppressants
  • are older
  • have had PC before

You’re more at risk for IC if:

  • you’re over age 50
  • you have or are at risk for heart disease
  • you have heart failure
  • you have low blood pressure
  • you have had an abdominal operation

What Are the Symptoms of Colitis?

Depending on your condition, you may experience one or more of the following symptoms:

  • abdominal pain or cramping
  • bloating in the abdomen
  • weight loss
  • diarrhea
  • blood in your stool
  • urgent need to move your bowels
  • chills and/or fever
  • vomiting

Diagnosing Colitis

Your doctor may ask about the frequency of your symptoms and when they first occurred. They'll perform a thorough physical exam and use diagnostic tests such as:

  • colonoscopy: camera on a flexible tube is threaded through the anus to view the rectum and colon
  • sigmoidoscopy: similar to colonoscopy but shows only the rectum and lower colon
  • stool samples
  • abdominal imaging such as MRI or CT scans
  • barium enema: X-ray of the colon after it's injected with barium, which helps make images more visible

Treating Colitis

Treatments vary by a few factors:

  • type of colitis
  • your age
  • overall physical condition


Anti-inflammatory medication may be used to treat swelling and pain, and antibiotics can treat infection. Your doctor may also treat you with pain medications (analgesics) or antispasmodics.


Surgery to remove part or all of your colon and/or rectum may be necessary if other treatments don’t work.

What Is to Be Expected in the Long Term?

Your outlook depends on the type of colitis you have. UC may require lifelong medication therapy unless you have surgery. Other types, such as IC, usually improve without surgery. PC generally responds well to antibiotics but may recur.

In all cases, early detection is critical to recovery. Early detection may help prevent other serious problems such as colon cancer. Let your doctor know about any symptoms you’re experiencing.

Written by: Brindles Lee Macon and Marijane Leonard
Edited by:
Medically Reviewed by:
Published: Jul 25, 2012
Published By: Healthline Networks, Inc.
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