Colitis inflammation is habitually found in the rectum and lower portion of the colon, but it may affect the entire colon. Colitis may affect any age of people, but usually indications begin between 15 and 30. Children and youngsters sometimes build up the disease but colitis is less common, as are sufferers over 50. Colitis inflammation inside the intestines causes' diarrhea, as the colon is unfilled most often. Ulcers occur where the colitis inflammation has killed the cells lining in the colon, which later bleed and produce pus.