Colitis is inflammation of your colon, also known as your large intestine. If you have colitis, 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.

The types of colitis and their causes

Ulcerative colitis (UC) is one of two conditions classified as inflammatory bowel disease. The other is Crohn’s disease.

UC is a life-long disease that produces inflammation and bleeding ulcers within the inner lining of your large intestine. It generally begins in your rectum and spreads to your colon.

UC is the most commonly diagnosed type of colitis. It occurs when your immune system overreacts to bacteria and other substances in your digestive tract, but experts don’t know why this happens. Common types of UC include:

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

Pseudomembranous colitis (PC) occurs from overgrowth of the bacterium Clostridium difficile. This kind of bacteria normally lives in your intestine but doesn’t cause problems because it’s balanced by the presence of “good” bacteria. Certain medications, especially antibiotics, may destroy healthy bacteria. This allows Clostridium difficile to take over, releasing toxins that cause inflammation.

Who is at risk for colitis

Different risk factors are associated with each type of colitis.

  • are between the ages of 15 and 30 (most common) or 60 and 80
  • are of Jewish or Caucasian descent
  • are taking long-term antibiotics
  • are hospitalized
  • are receiving chemotherapy
  • are taking immunosuppressant drugs
  • have had PC before

Symptoms of colitis

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

  • abdominal pain or cramping
  • bloating in your abdomen
  • weight loss
  • diarrhea with or without blood
  • blood in your stool
  • urgent need to move your bowels
  • vomiting


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, may 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 complications. Let your doctor know about any symptoms you’re experiencing.