Cause Medical experts do not know what causes Crohn's disease but believe a genetic disorder is involved. There is a greater chance of developing the disease when a family history exists. Recurring inflammation in a part or parts of the intestine is characteristic of this disease. The immune system, triggered by the stimulus, attacks the lining of the intestine. Once rare, Crohn's disease is becoming more common - the number of cases reported has doubled in the past 30 years with 30,000 Americans diagnosed with the disease annually.
Young adults are more likely to develop the disorder than older people.
Those whose relatives have the disease and those who are known to have food allergies are the most likely to experience Crohn's disease. In about a third of all cases, there is chronic inflammation of the small intestine only, usually just the final section. Half the cases show inflammation in both the small and large intestines, usually in the end of the small intestine and upper part of the large. The patient may also experience some abdominal swelling and tenderness. Mouth lesions are common, and about a third of patients also develop anal abscesses.