The causes of Crohn's disease are unknown, but researchers believe the immune system attacks the GI tract due to a virus or bacteria, according to Mayo Clinic, and heredity may also play a role. Crohn's disease involves the inflammation of the digestive tract lining and is classified as a chronic inflammatory bowel disease. The condition may affect different areas of the digestive tract, and it may spread to deeper tissues.
In Crohn's disease, harmless bacteria in the gastrointestinal tract, which are ignored by a healthy immune system, are detected as harmful and attacked by a malfunctioning immune system, according to the Crohn's and Colitis Foundation of America. This results in an inflammatory immune response that does not subside, causing the lining of the gastrointestinal tract to thicken or become ulcerated. Crohn's disease is most common in adolescents ages 15 to 35, and it is equally common in both genders. Although the exact cause is not well understood as of 2015, genetic and environmental factors may play a role. Diet and stress factors may aggravate the illness.
Although symptoms vary, the gastrointestinal symptoms of Crohn's disease may include the urgent need to have a bowel movement, bleeding from the rectum, abdominal cramps, persistent diarrhea, the sensation of an incomplete bowel movement and constipation, as confirmed by the Crohn's and Colitis Foundation of America. Patients may also experience loss of appetite, fever, weight loss, fatigue and night sweats. Female patients may lose their normal menstrual cycle. Patients generally experience flare-ups of symptoms followed by remission periods.