Ulcertaive Colitis is an inflammatory bowel disease that begins in the lowest part of the colon (near the rectum) and moves up the colon in a continuous fashion. This is different from Crohn’s, which can skip around and affect any part of the gastrointestinal tract. UC also rarely has blood in the stool, but can present with lots of pain and cramping with bowel movements, as well as bowel urgency and frequency.
Colitis is diagnosed by visualization of the colon via sigmoidoscopy or colonoscopy and biopsy of any suspicious areas of inflammation.
Inflammatory bowel disease in general is driven by the formation and continuation of inflammation induced by the immune system.