[HPO Definition]: A chronic granulomatous inflammatory disease of the intestines that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms. It primarily causes abdominal pain, diarrhea which may be bloody, vomiting, or weight loss, but may also cause complications outside of the gastrointestinal tract such as skin rashes, arthritis, inflammation of the eye, tiredness, and lack of concentration. Crohn's disease is thought to be an autoimmune disease, in which the body's immune system attacks the gastrointestinal tract, causing inflammation. [HPO:sdoelken]

[NCI-GLOSS Definition]: A condition in which the gastrointestinal tract is inflamed over a long period of time. Regional enteritis usually affects the small intestine and colon. Symptoms include fever, diarrhea, stomach cramps, vomiting, and weight loss. Regional enteritis increases the risk of colorectal cancer and small intestine cancer. It is a type of inflammatory bowel disease (IBD).

[NICHD Definition]: A chronic, transmural inflammation that can affect any location along the gastrointestinal tract.

[PDQ Definition]: A gastrointestinal disorder characterized by chronic inflammation involving all layers of the intestinal wall, noncaseating granulomas affecting the intestinal wall and regional lymph nodes, and transmural fibrosis. Crohn disease most commonly involves the terminal ileum; the colon is the second most common site of involvement. Check for active clinical trials using this agent. (NCI Thesaurus)

[GARD Definition]: Crohn's disease is a type of inflammatory bowel disease (IBD), the general name for conditions that cause inflammation in the intestines. Common signs and symptoms include abdominal pain and diarrhea. Bleeding from the rectum, weight loss, joint pain, skin problems and fever may also occur. Other problems can include intestinal blockage and malnutrition. Crohn's disease can occur in people of all age groups but is most often diagnosed in young adults. The exact cause is unknown, but is thought to involve both genetic and environmental factors. It appears to run in some families. Treatment is aimed at relieving symptoms and reducing inflammation, but some people require surgery. Quitting smoking can also improve the symptoms of Crohn's disease. - this information is from GARD/ORDR/NCATS.