Crohn's disease is an ongoing disorder that causes inflammation of the digestive tract, also referred to as the gastrointestinal (GI) tract. Crohn's disease can affect any area of the GI tract, from the mouth to the anus, but it most commonly affects the lower part of the small intestine, called the ileum. The
swelling extends deep into the lining of the affected organ. The swelling can cause pain and can make the intestines empty frequently, resulting in diarrhea. Crohn's disease is an inflammatory bowel
disease, the general name for diseases that cause swelling in the intestines. Because the symptoms of Crohn's disease are similar to other intestinal disorders, such as irritable bowel syndrome and ulcerative colitis, it can be difficult to diagnose. Ulcerative colitis causes inflammation and ulcers in the top layer of the lining of the large intestine. In Crohn's disease, all layers of the intestine may be involved, and normal healthy bowel can be found between sections of diseased bowel. Crohn's disease affects men and women equally and seems to run in some families. About 20 percent of people with Crohn's
disease have a blood relative with some form of inflammatory bowel disease, most often a brother or sister and sometimes a parent or child. Crohn's disease can occur in people of all age groups, but it is more often diagnosed in people between the ages of 20 and 30. People of Jewish heritage have an increased risk of developing Crohn's disease, and African Americans are at decreased risk for developing Crohn’s disease. Crohn’s disease may also be called ileitis or enteritis.
What causes Crohn’s disease?
Several theories exist about what causes Crohn’s disease, but none have been proven. The human immune system is made from cells and different proteins that protect people from infection. The most popular theory is that the body’s immune system reacts abnormally in people with Crohn’s disease, mistaking bacteria, foods, and other substances for being foreign. The immune system’s response is to attack these “invaders.” During this process, white blood cells accumulate in the lining of the intestines, producing chronic inlammation, which leads to ulcerations and bowel injury. Scientists do not know if the abnormality in the functioning of the immune system in people with Crohn’s disease is a cause, or a result, of the disease. Research shows that the inlammation seen in the GI tract of people with Crohn’s disease involves several factors: the genes the patient has inherited, the immune system itself, and the environment. Foreign substances, also referred to as antigens, are found in the environment. One possible cause for inlammation may be the body’s reaction to these antigens, or
that the antigens themselves are the cause for the inlammation. Scientists have found that high levels of a protein produced by the immune system, called tumor necrosis factor (TNF), are present in people with Crohn’s disease.