Ileitis, terminal: Crohn's disease, a chronic inflammatory disease of the intestine involving only the end of the small intestine (the terminal ileum). Crohn's disease affects primarily the small and large intestines but which can occur anywhere in the digestive system between the mouth and the anus. Named after Burrill Crohn who described the disease in 1932. The disease often strikes persons in their teens or early twenties. It tends to be chronic, recurrent with periods of remission and exacerbation. In the early stages, it causes small scattered shallow crater-like areas (erosions) called aphthous ulcers in the inner surface of the bowel. With time, deeper and larger ulcers develop, causing scarring and stiffness of the bowel and the bowel becomes increasingly narrowed, leading to obstruction. Deep ulcers can puncture holes in the bowel wall, leading to infection in the abdominal cavity (peritonitis) and in adjacent organs Abdominal pain, diarrhea, vomiting, fever, and weight loss can be symptoms. Crohn's disease can be associated with reddish tender skin nodules, and inflammation of the joints, spine, eyes, and liver.