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Types of Inflammatory Bowel Disease

Inflammatory bowel disease, or IBD, is a condition in which there is chronic or recurring inflammation of the gastrointestinal, or GI, tract. In a type of IBD called ulcerative colitis, the condition is limited to the colon, also known as the large intestine. In another type known as Crohn’s disease, the condition most commonly affects the small intestine and colon, but it can occur anywhere in the gastrointestinal tract.

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Doctors at NYU Langone’s Inflammatory Bowel Disease Center and Inflammatory Bowel Disease Center—Long Island use advanced diagnostic techniques to identify the type of IBD that is causing your symptoms and recommend the appropriate medical or surgical treatment to alleviate symptoms and achieve remission.

The cause of IBD is not known, but research suggests that in people with the condition, the body’s immune system may perceive food, bacteria, and other substances in the intestines as a threat. In response, the immune system sends white blood cells to the intestines, causing inflammation that triggers abdominal pain and other symptoms.

In addition, IBD prevents the intestines from absorbing essential nutrients in digested food, which can lead to malnutrition.

IBD can run in families, and men and women are diagnosed in equal numbers. Most people receive the diagnosis between the ages of 15 and 30. However, the condition can develop at any age.

Without treatment, symptoms of IBD may worsen over time. In some instances, chronic inflammation can lead to serious complications, such as open sores, called ulcers, or tears in the intestinal lining. In addition, having IBD for more than eight years increases the risk of colorectal cancer and requires regular testing to screen for the disease. The risk is higher in those who have extensive intestinal damage and those with a family history of colorectal cancer.

Irritable bowel syndrome, or IBS, is not a type of inflammatory bowel disease, although it has similar symptoms. Our doctors can distinguish between the conditions. They use different diagnostic and treatment approaches for each.

Both Crohn’s disease and ulcerative colitis often require lifelong medical treatment and monitoring to keep the disease and its symptoms under control.

Crohn’s Disease

In Crohn’s disease, inflammation can occur anywhere in the gastrointestinal tract, from the mouth to the anus. It often affects the end of the small intestine, called the ileum, and the beginning of the colon, or large intestine. Crohn’s disease affects the entire thickness of the intestinal or bowel wall and may not be limited to one area; there may be areas of healthy intestine between diseased sections.

Chronic inflammation may cause ulcers to form on the lining of the intestines. In some people, severe Crohn’s disease may result in fistulas, or ulcers that form tunnels through the intestinal wall, connecting two organs. A fistula may connect different parts of the intestines or the intestine and another organ, such as the bladder or skin.

Crohn’s disease may also cause strictures, or scarring, on the intestinal wall. This narrows the intestinal tract and may cause an obstruction, leading to constipation and abdominal pain.

Because Crohn’s disease tends to affect the small intestine, it does not always cause alarming symptoms when it first develops. Some people may experience irregular bowel movements or cramping for years without receiving a diagnosis of IBD.

When symptoms worsen, they typically include one or more of the following: persistent diarrhea, bloody stool, abdominal pain, constipation, loss of appetite, fatigue, and unexpected weight loss.

If the inflammatory response that causes gastrointestinal symptoms starts to affect other parts of the body, you may experience one or more symptoms that seem unrelated to Crohn’s disease. They may include fever; mouth ulcers, such as canker sores; skin rashes; arthritis; and eye inflammation, which may cause blurry vision, irritation, or redness.

Ulcerative Colitis

Like Crohn’s disease, ulcerative colitis involves inflammation of the gastrointestinal tract. In this condition, however, only the lining of the large intestine, or colon, is affected. Ulcerative colitis causes multiple ulcers to form on the intestinal wall.

Most of the time, ulcerative colitis first affects the bottom part of the large intestine, near the rectum, and symptoms develop quickly. They include urgent and frequent bowel movements, persistent diarrhea, incontinence, rectal bleeding and pain, bloody stool, abdominal pain, and cramping.

Because ulcerative colitis is thought to be caused by an abnormal immune system response, a person may also experience a loss of appetite, unexpected weight loss, fatigue, skin rashes, and arthritis.

Ulcerative colitis is a chronic condition, but symptoms may come and go in unpredictable patterns. Sometimes, months or years may pass between flare-ups.

Our Research and Education in Inflammatory Bowel Disease

Learn more about our research and professional education opportunities.