The digestive system.
Crohn's disease causes inflammation in the small intestine.
Crohn's disease usually occurs in the lower part of the small
intestine, called the ileum, but it can affect any part of the
digestive tract, from the mouth to the anus. The inflammation
extends deep into the lining of the affected organ. The
inflammation can cause pain and can make the intestines empty
frequently, resulting in diarrhea.
Crohn's disease is an inflammatory bowel disease (IBD), the
general name for diseases that cause inflammation in the
intestines. Crohn's disease can be difficult to diagnose because
its symptoms are similar to other intestinal disorders such as
irritable bowel syndrome and to another type of IBD called
ulcerative colitis. Ulcerative colitis causes inflammation and
ulcers in the top layer of the lining of the large intestine.
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 IBD, most often
a brother or sister and sometimes a parent or child.
Crohn's disease may also be called ileitis or enteritis.
What causes Crohn's disease?
Theories about what causes Crohn's disease abound, but none
has been proven. The most popular theory is that the body's
immune system reacts to a virus or a bacterium by causing
ongoing inflammation in the intestine.
People with Crohn's disease tend to have abnormalities of the
immune system, but doctors do not know whether these
abnormalities are a cause or result of the disease. Crohn's
disease is not caused by emotional distress.
What are the symptoms?
The most common symptoms of Crohn's disease are abdominal
pain, often in the lower right area, and diarrhea. Rectal
bleeding, weight loss, and fever may lso occur. Bleeding may be
serious and persistent, leading to anemia. Children with Crohn's
disease may suffer delayed development and stunted growth.