Crohn's disease is a chronic condition in which there is chronic inflammation in the gastrointestinal (GI) tract or "bowel." It is one type of inflammatory bowel disease (IBD). Another type of IBD is ulcerative colitis. While Crohn's disease can affect any part of the digestive system, it occurs more commonly in the ileum (part of the small intestine) and colon (large intestine).
Most cases of Crohn's disease are diagnosed before the age of 30, but it can affect people of any age group. Crohn's disease isn't usually fatal, but it can be a lifelong inconvenience. There is no definitive cure.
The exact cause of Crohn's disease is unclear, although there is clearly an autoimmune element. That means the body's natural defenses, which are normally supposed to fight infection, attack the body's own tissue and fail to distinguish the body itself from foreign material in the body. Autoimmune diseases run in families. About one-quarter of Crohn's patients have relatives who also suffer from IBD.
It is also believed that a virus or bacteria may be involved, which may cause the initial damage to the lining of the GI tract. However, it is not yet known which organism might be involved.
The first signs of Crohn's disease are usually abdominal pains and diarrhea after eating. Other symptoms include:
Some symptoms do not affect the digestive system. These include joint pain, eye inflammation or red eye, and skin problems.
Crohn's disease tends to come and go. A person can often go months without a symptom. During a flare-up, the bleeding can be quite severe. Some people with active Crohn's disease develop anemia (lack of blood iron from blood loss), leading to weakness and pale skin.
Crohn's disease is associated with several complications, many of which are linked to the constant inflammation of the bowel and to the person's abnormal immune system. Here are some of the most common ones:
A few people with Crohn's disease have no problems in the short term except for one or more symptoms such as skin lesions or arthritis. These people sometimes wait years before they are diagnosed with Crohn's disease.