Learn about Inflammatory Bowel Disease

What is IBD

Inflamatory Bowel Disease (IBD) describes a group of conditions in which the intestines become inflamed. The two most common inflammatory bowel diseases are Crohn’s disease and ulcerative colitis. Another form of IBD is microscopic colitis. 

There is no official database which gives accurate figures, but it is thought that at least 40,000 people are living with IBD in Ireland. There were 5.9 new cases of Crohn’s disease in Ireland per 100,000 population in 2011 and 14.9 new cases of ulcerative colitis. The incidence of Crohn's disease is higher than ulcerative colitis in children. Males and females are affected equally and patients can be diagnosed at any age, including babies and children. The peak age of incidence is between the ages of 15 and 35, with a second (smaller) peak from the 50s to 70s. IBD diagnosed in children can behave differently and can be treated differently to that diagnosed in adults.

Crohn’s disease can affect any part of the gastrointestinal tract from mouth to anus. Ulcerative colitis is restricted to the large intestine (colon). There is currently no known cause or cure for IBD.

While Crohn's disease and ulcerative colitis can behave differently, they do have some common features. They are marked by an abnormal response by the body’s immune system, leading to swollen, inflamed and ulcerated intestines.

The main difference between Crohn’s disease and ulcerative colitis relates to the depth of inflammation. In ulcerative colitis, inflammation usually affects only the mucosa (inner lining of the intestine). In Crohn’s disease, the inflammation can be deeper into the tissue and even perforate the bowel in severe cases.

In Crohn’s disease there are usually patchy or discontinuous areas of inflammation (known as skip lesions) whereas in ulcerative colitis, there is a continuous area of inflammation.

Despite extensive worldwide research over many decades, the precise cause(s) of Crohn’s disease and ulcerative colitis have not yet been identified. Many scientists believe that the interaction of an outside agent, such as a virus or bacterium with the body’s immune system may trigger an inflammatory response in the intestinal tract that continues without control.

There has been an increase in the incidence of IBD over the past number of decades which leads scientists to believe that environmental factors contribute to the cause of the disease, as well as there being a known genetic component.

IBD is not to be confused with IBS which stands for Irritable Bowel Syndrome.