With regard to intestinal complications, people with colitis often have irritation around the anus. Bleeding from the bowel can cause a low blood count. There is a risk of developing cancer in the bowel after 10 to 20 years of having the illness. With Crohn's disease, the most common problem is scarring or narrowing in the furthest part of the small intestine. Fissures, which are cracks in the skin in the anus, and hemorrhoids are common in both conditions.
Complications can occur outside the intestine.
Some people with Crohn's disease or colitis also get arthritis. Skin rashes can occur. Ulcers in the mouth are very common. People between the age of 15 and 35 seem to be the most susceptible. There is a tendency for the children and relatives of people with Crohn's disease and colitis to develop these conditions.