Colitis is an inflammatory bowel disease (IBD) that leads to the inflammation of the delicate membrane lining the colon more commonly known as the large intestine or bowel. Colitis typically causes inflammation and sores known as ulcers in the top layers of the lining of the large intestine. This disorder rarely affects the small intestine aside from the lower section that is known as the ileum. Types of IBDs that lead to the development of colitis include ulcerative colitis, which is the most common type of colitis, Crohn's colitis, diversion colitis, ischemic colitis, infectious colitis, fulminant colitis, chemical colitis, microscopic colitis, and atypical colitis.

Colitis typically affects individuals who are under 30 years of age and in rare cases it also affects individuals who are 60 years of age or older.

Causes and Risk Factors

The causes of colitis are unclear despite the fact that colitis is a very common disorder. The disease is further complicated because many contributing factors may only incite this condition in certain people. Factors that can possibly lead to colitis are:

	Immune System: Ironically, the body’s own immune system can cause colitis while attempting to remove any virus or bacteria that is present in the body. The immune system sometimes overreacts and causes inflammation in the colon. In some cases, the microorganisms that invade the body cause inflammation by generating an immune response.
	Heredity: This may not be a direct cause but heredity is a definite risk factor. Although the risk is not dramatically higher, individuals with a family history of colitis are more likely to develop it than others who lack such history.