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Unknown: Crohn Disease

Unknown: Crohn Disease

Causes and Symptoms
The Future
For more information


Crohn disease is a chronic (long-term) disease of the digestive tract marked by severe inflammation. It may involve any part of the digestive system from the mouth to the rectum, but is most likely to affect the small intestine and the area around the anus. Crohn disease is similar to ulcerative colitis, another disease of the digestive system that is sometimes categorized together with Crohn disease as inflammatory bowel disease (IBD). The major difference between ulcerative colitis and Crohn disease is that ulcerative colitis is usually restricted to the large intestine and involves the upper layers of the bowel lining, while Crohn disease can occur anywhere in the digestive tract and affects deeper layers of tissue.

Crohn disease is named for Burrill Bernard Crohn (1884–1983), a gastroenterologist (doctor who specializes in diseases of the digestive system) who treated patients at Mount Sinai Hospital in New York City.


Crohn disease is a chronic inflammatory disorder of the digestive system that is thought to be caused by an abnormal response of the body's immune system to bacteria in the digestive tract. A gene was identified in 2006 that may also be linked to the disease. Crohn disease is marked by breaks in the lining of the digestive tract, commonly in the small intestine, that cause cramps, nausea, persistent diarrhea, fever, and rectal bleeding. The symptoms vary in severity from patient to patient; some people may have only occasional episodes of diarrhea, for example, while others may have twenty to thirty bowel movements in a single day that

interfere with sleep, work, school, or other activities. In addition, it is not unusual for patients with Crohn disease to have sections of normal healthy bowel alternating with sections of diseased bowel tissue.

In one type of Crohn disease, sometimes called penetrating Crohn disease, the underlying layers of intestinal tissue are damaged also, leading to perforation (puncturing) of the intestinal wall. This may cause a serious infection in the abdomen or the formation of fistulas, abnormal passageways leading from one loop of the intestine to another or from the abdomen to the outside of the body. These fistulas, present in about 30 percent of patients, are most likely to form in the area around the anus, leading to the formation of abscesses.

Another subtype of Crohn disease is called stricturing disease. Stricture is the medical term for an abnormal narrowing of a hollow organ such as the bowel. The inflammation and swelling of tissue inside the bowel leads to changes in the size of the patient's stools and eventual blockage of the intestinal passages. Severe abdominal cramping is often an indication of stricturing disease, as are nausea and vomiting.

In addition to intestinal problems, Crohn disease can produce long-term complications including skin ulcers, mouth ulcers similar to canker sores, eye disorders, inflammation of the liver, and joint pains or arthritis.


It is estimated that there are about 500,000 persons with Crohn disease in the United States, with another 500,000 suffering from ulcerative colitis. Another statistic given by some doctors is seven cases per 100,000 in the general population in Canada and the United States. Crohn is primarily a disorder of adults, most often beginning in late adolescence or the early adult years. The most common age at onset is between fifteen and thirty years, although the disorder may begin at any age.

The rate of Crohn disease in North America has been increasing since the 1960s, although the reasons for the increase are unknown. Southern Europe, South America, Africa, and Asia have considerably lower rates of the disease—as low as 0.5–0.08 cases per 100,000 people.

Around the world, however, the rates of Crohn disease are higher in cities than in rural areas and higher among people with higher incomes than among lower-income groups.

One argument for suspecting a genetic factor in Crohn disease is that it runs in some families; people with siblings who have the disease are thirty times more likely to develop it than the normal population. It is also relatively common among certain ethnic groups, particularly Jews of Eastern European origin. A two- to four-fold increase in the frequency of Crohn disease has been found among the Jewish population in the United States, Europe, and South Africa compared to other ethnic groups.

A Presidential Emergency

Many people know that President Dwight D. Eisenhower (1890–1969) had a heart attack during his first term in the White House. What is less well known, however, is that Eisenhower also suffered from the stricturing form of Crohn disease. In the early hours of June 8, 1956, the president awoke with vague pains in his lower abdomen that gradually got worse over the next hours. The surgeons were concerned about the risks of an operation because Eisenhower had his heart attack just nine months before.

In spite of the risks of surgery, the president's doctors decided that an untreated bowel obstruction was even more dangerous. They discovered when they opened Eisenhower's abdomen that he did indeed have a stricture from Crohn disease that could have killed him. The surgeons bypassed the obstruction and reconnected healthy portions of the president's intestines. Ike was back at his desk conducting official business only five days after the surgery.

In terms of other ethnic groups in the United States, Crohn disease appears to be slightly more common in non-Jewish Caucasians than in African or Asian Americans. The disease is almost twice as likely to occur in men than in women.

Causes and Symptoms

The causes of Crohn disease are not completely understood. It is known that smoking is a risk factor for developing Crohn. At one time it was thought that the disease was caused by emotional stress or by diet, particularly by eating sweet or high-fat foods. The most common theory, however, holds that the disease is caused by the patient's immune system mistaking bacteria that normally live in the intestine, and possibly certain foods, as foreign substances that must be attacked. When the immune system over-reacts, white blood cells move in large numbers to the intestines, where they accumulate and eventually cause swelling and destruction of tissue.

In addition to the symptoms that have already been described, patients with Crohn disease may experience:

  • General lack of energy
  • Loss of appetite
  • Intestinal gas
  • Nutritional deficiencies resulting from poor absorption of nutrients from food
  • In children, delayed growth


No single test can be used to diagnose Crohn disease. In addition to blood tests to check for anemia and stool tests to check for blood in the stool, the four tests most commonly used to diagnose Crohn are barium studies, computed tomography (CT) scans, sigmoidoscopies, and colonoscopies. In a barium study, the patient is given barium in enema form to coat the lining of the colon and rectum. Air is then blown into the colon in order to fill it. The resultant x-ray can detect abnormalities in the lining of the intestine. CT scans are useful in detecting fistulas and abscesses.

Sigmoidoscopies and colonoscopies require special equipment inserted into the patient's body. A sigmoidoscope is a flexible lighted tube that can be inserted into the rectum and used to examine the last 2 feet (0.6 meters) of the colon. This procedure can be done in a doctor's office but does not provide a view of the entire colon. A colonoscope is a long flexible tube attached to a video camera and monitor that allows the doctor to examine the entire length of the patient's colon and rectum. The patient must take a laxative the night before to cleanse the bowel and

may be given a sedative in the doctor's office to make them more comfortable. The doctor can take tissue samples from the lining of the bowel for analysis.


There is no medical or surgical cure for Crohn disease. Treatment consists of managing the patient's symptoms, getting the disease into remission, and preventing relapses.

Patients may be given one or more different types of medications to relieve pain and discomfort including cortisone and other drugs that reduce inflammation; drugs that block or lower the body's immune response; antidiarrheal drugs and fluid replacements; antibiotics; and nutritional supplements. Special high-calorie liquid formulas may be prescribed. Although doctors no longer think that diet causes Crohn disease, they usually advise patients who are having a flare-up to avoid bulky grains, spicy foods, alcohol, and milk products until their symptoms diminish.

Patients who are not helped by medications or who have structuring Crohn disease are usually treated by surgery. In most cases the surgeon removes the diseased part of the intestine and reconnects the healthy portions. This procedure may have to be repeated, however, if inflammation develops in the area of the intestine next to where a diseased portion was removed. In cases in which the disease is located in the large intestine (colon), the surgeon may have to remove the entire colon in a procedure called a colostomy. In this procedure, an opening called a stoma is made in the wall of the abdomen, and a portion of the remaining colon is attached to the stoma. The person's body wastes pass through the stoma and are collected in a special bag attached to the outside of the body.

Another type of surgery for patients with stricturing Crohn disease involves widening the intestine at the point of the stricture.


Most people with Crohn disease have periods of remission and are able to hold jobs and generally lead normal lives. Medical treatment of Crohn disease, however, becomes less effective over time; about 80 percent of patients require surgery eventually. In addition, the disease can recur after surgery. The chance of a shortened life span or serious complications increases with the duration of the illness; patients with Crohn disease

have an increased risk of colorectal cancer. The disease itself, however, is rarely fatal.


There is no known way to prevent Crohn disease, because its causes are not yet understood.

The Future

It is possible that the incidence of Crohn disease will continue to rise as it has for the past fifty years. New treatments and new diagnostic techniques for the disease are currently at the clinical trials stage; as of spring 2008, the National Institutes of Health was conducting over 200 separate trials of new drugs and other types of treatment for the disorder.

SEE ALSO Canker sores; Colorectal cancer; Irritable bowel syndrome


Abscess: A pus-filled sore surrounded by inflamed tissue.

Fistula: An abnormal tunnel or passage that forms between one part of the intestine and another or between the intestine and the body surface.

Gastroenterologist: A doctor who specializes in diagnosing and treating diseases of the digestive system.

Remission: A period in the course of a disease when symptoms disappear for a time.

Stoma: An opening made in the abdomen following surgery for colon cancer that allows wastes to pass from the body.

Stricture: The medical term for an abnormal narrowing of a hollow organ like the bowel.

For more information


Giddens, Sandra, and Owen Giddens. Everything You Need to Know aboutCrohn's Disease and Ulcerative Colitis. New York: Rosen Publishing Group, 2004.

Sklar, Jill. Crohn's Disease and Ulcerative Colitis: An Essential Guide for the NewlyDiagnosed, rev. ed. New York: Marlowe and Co., 2007.

Warner, Andrew S., and Amy E. Barto. 100 Questions and Answers about Crohn's Disease and Ulcerative Colitis: A Lahey Clinic Guide. Sudbury, MA: Jones and Bartlett Publishers, 2007.


American Academy of Family Practice (AAFP). “Patient Information: Crohn's Disease.” American Family Physician, August 15, 2003. Available online at (accessed June 2, 2008).

Bakalar, Nicholas. “Crohn's Disease and Colitis Are Linked to Mutant Gene.” New York Times, November 7, 2006. Available online at C1A9609C8B63 (accessed June 2, 2008).


Crohn's and Colitis Foundation of America (CCFA). About Crohn's Disease. Available online at (accessed June 2, 2008).

Mayo Clinic. Crohn'sDisease. Available online at (updated May 9, 2008; accessed June 2, 2008).

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Crohn's Disease. Available online at (updated February 2006; accessed June 2, 2008).

TeensHealth. Inflammatory Bowel Disease. Available online at (updated May 2007; accessed June 2, 2008).

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