Crohn
Crohn's disease is a type of inflammatory bowel disease that may affect any segment of the gastrointestinal tract from the mouth to the anus. Symptoms often include abdominal pain, diarrhea, fever, abdominal distension, and weight loss. Other complications outside the gastrointestinal tract may include anemia, skin rashes, arthritis, inflammation of the eye, and fatigue. The skin rashes may be due to infections as well as pyoderma gangrenosum or erythema nodosum. Bowel obstruction may occur as a complication of chronic inflammation, and those with the disease are at greater risk of colon cancer and small bowel cancer. While the precise causes of Crohn's disease are unknown, it is believed to be caused by a combination of environmental, immune, and bacterial factors in genetically susceptible individuals. It results in a chronic inflammatory disorder, in which the body's immune system defends the gastrointestinal tract, possibly targeting microbial antigens.