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Crohn's Disease

What Is Crohn's Disease?

Crohn’s disease, also known as regional ileitis, is a chronic inflammatory bowel disease that causes swelling and ulcers in the lining of the intestinal tract, usually in the small intestine, colon, and/or anal area.  Less often, the upper digestive tract may also be affected. The inflammation involves deep layers of the intestinal wall, where ulcers and abscesses may form.

The ulcers may erode the wall completely, creating abnormal passages or fistulas to other parts of the intestine, to other organs such as the bladder, or to the skin. Deep cracks called fissures may also develop in and around the anus. Inflammation may thicken the intestinal wall until the passageway becomes blocked.  Some people suffer only one or two attacks before entering into permanent remission; others experience recurrent attacks over a lifetime. Crohn’s disease is not widespread, but the incidence among the general population has been increasing in recent decades.

Crohn's disease is classified by location:

  • The most common type isileocolitis********, which develops in the small intestine and colon. Ileitis occurs in the small intestine only.
  • Crohn'scolitis only affects the colon.
  • Gastrodudenal Crohn's disease is less common, and occurs when the stomach and duodenum, which is the first part of the small intestine, develop inflammation****.****
  • Jejunoileitisrefers to patchy inflammation in the upper portion of the small intestine.
  • Perianal Crohn’s disease affects the anal area and can be seen with or without disease in the rest of the intestine.

Who Gets Crohn's Disease?

The United States now has one of the highest rates of Crohn's disease in the world, with an estimated 1.4 million Americans living with this condition, many who were diagnosed before age 30.  Crohn's disease is more common in urban communities and northern climates than in rural communities and southern climates.

Crohn's disease affects Caucasians more often than other ethnic groups, but the rate is increasing among African Americans. Ashkenazi Jews of Eastern European heritage are four to five times more likely to develop Crohn's disease than the general population. The disorder is less common among Hispanics and Asian Americans.

Crohn's disease occurs in men and women almost equally, and can develop at any age. Onset between the ages of 15 and 35 is most common. The disorder may be genetic and often runs in families. Up to 25 percent of patients who have Crohn’s disease have a relative who also has the disease. Having a relative with Crohn's disease increases the risk tenfold, and if the relative is a sibling, the risk is thirty times higher.


Crohn’s disease symptoms appear during flare-ups, which alternate with periods of remission. Symptoms often mimic other gastrointestinal disorders and can include:

  • Spasms of abdominal pain or cramps, often located near the navel or in the lower right


  • Persistent watery diarrhea.

  • Rectal bleeding or blood in the stool.

  • Anal fissures.

  • Loss of appetite and weight.

  • Systemic complications such as joint pain from arthritis, inflammation of the eyes, and skin lesions.

Causes/Risk Factors

  • The cause of Crohn’s disease is unknown although researchers suspect the immune system and genetics play a role.
  • Family history of the disease. A genetic mutation (Nod2 gene, CARD15 gene) appears to influence the immune system, causing it to malfunction. Because Crohn's disease runs in families, this defective gene may be passed from one generation to the next. There have now been over a hundred genes discovered that can lead to a risk of inflammatory bowel disease.
  • Various theories suggest viral or bacterial infections, autoimmune disorders, food allergies, or lymphatic obstruction.
  • Environment; the condition appears to be more common in urban areas.

What If You Do Nothing?

While Crohn's disease symptoms may go into remission, the illness can progress and potentially cause complications, including gastrointestinal problems and infection.


Following a physical exam and patient history, your doctor may order the following:

  • Blood tests. A blood sample can identify low red blood cell counts, which indicate anemia and inflammation, and low levels of electrolytes and the protein albumin, which may indicate malnourishment. If Crohn's disease is suspected, levels of other proteins and substances in the blood can provide clues about how active the inflammation is.
  • Imaging tests. Different types of imaging tests can indicate where the disease is concentrated, how far it has spread, and whether any complications have developed. The most common tests include the following:
  • Endoscopy—In this test, the physician uses a flexible, lighted tube with a camera attached to take pictures of various locations in the digestive tract. Endoscopy provides information about inflammation, bleeding, and other problems. When this test is performed in the lower digestive tract, it is called a colonoscopy. When only the upper part of the digestive tract is examined, it is called anupper endoscopy. When the lower large intestine is examined it is called a sigmoidoscopy.
  • During an endoscopic procedure, a sample of gastrointestinal tissue may be obtained to distinguish Crohn's disease from other gastrointestinal disorders such as ulcerative colitis.
  • Barium contrast studies—In these tests, x-rays are used to determine the location and severity of the inflammation. Prior to the test, patients drink a contrast substance called barium, which provides better images of the small intestine than regular x-rays. A small bowel follow-through, which focuses on the small intestine, can show images that are not detected in a standard colonoscopy. Sometimes, a barium enema is performed if Crohn's disease of the colon and rectum is suspected.
  • Computed tomography scans, ultrasound, or magnetic resonance imaging scan These tests can be used to detect complications of Crohn's disease, such as abscesses, fistulas, or problems with the liver, kidneys, or bile duct.
  • Wireless capsule endoscopy. This test involves swallowing a tiny camera that looks like a pill. It passes into the small intestine and takes photographs of those areas that are hard to reach with endoscopy. The camera is passed into the stool and the recorder is given back to the doctor, who reviews the pictures.


  • For mild attacks, over-the-counter antidiarrheal medications and pain relievers may be taken. Patients need to be sure they also replace water and electrolytes lost during diarrhea attacks by consuming plenty of fluids.
  • Anti-inflammatory medications, such as sulfasalazine or corticosteroids, can reduce inflammation for mild to moderate cases. The most common is sulfasalazine; however, patients who cannot tolerate this drug often are prescribed 5-ASA agents such as Lialda, Apriso, Delzicol, Asacol HD, or Pentasa. People who are allergic to sulfa drugs should not take sulfasalazine. Corticosteroids are typically used only at the beginning of the illness and only for a short time, generally three to four months. Corticosteroids can have seriousside effects, including bone fractures, cataracts, type 2 diabetes, osteoporosis, and high blood pressure. Corticosteroids also can increase the risk for infection, and can cause night sweats, puffiness in the face, additional facial hair, insomnia, and hyperactivity. Children who take them long term may have stunted growth. Patients taking corticosteroids often start with a higher dose to alleviate immediate symptoms and once these symptoms are under control, the dose is lowered. Prednisone is a commonly prescribed generic corticosteroid. Another common steroid used in Crohn’s disease is budesonide (Entocort.)  Anti-inflammatory medicines can be given by mouth or directly into the anus by suppository or enema.
  • Injectable medications are approved by the U.S. Food and Drug Administration to treat moderate to severe Crohn's disease in patients who cannot tolerate, have failed, or have persistent symptoms on other medications. These drugs can also be used to help heal fistulas. Researchers are investigating other possible uses. The medications include infliximab (Remicade), adalimumab (Humira), certolizumab (Cimzia), and vedolizumab (Entyvio.) Side effects include muscle pain, rash, fever, sore throat, headache, infection, and other possible serious side effects that should be discussed with your doctor.
  • . Many different antibiotics are prescribed to treat bacterial infections caused by fistulas, intestinal blockage, or surgery.
  • Enemas containing corticosteroids or aspirin-like drugs may be used to treat internal inflammation.
  • Immunosuppressive drugs may be prescribed on a long-term basis to quell autoimmune activity. Some commonly used medicines include azathioprine, 6-MP, and methotrexate.
  • Dietary changes. Soft, bland foods may need to replace spicy or high-fiber foods that can be tougher on the digestive system. Vitamin or mineral supplements or vitamin B12 injections, can replace nutrients lost from poor bowel absorption. Crohn’s disease in the small intestine can lead to lactose intolerance and so lactose-free foods can be chose.
  • Manage stress. While stress does not cause Crohn's disease, stress can aggravate symptoms. Preparation can minimize stress, such as knowing where public restrooms are in advance of an outing, for example, or bringing extra clothing to a dinner party may help the patient to feel more at ease. When traveling, patients who have Crohn's disease should always make sure to take enough medication.
  • Intravenous feeding allows the bowel to rest for more severe cases.
  • Surgery may be required to repair blockages, fistulas, or abscesses in the rectum or intestine. Many Crohn's disease patients may eventually require surgery to relieve symptoms or treat complications, such as stricture, abscess, fistulas, bleeding, or anal fissures. Surgery is not helpful in all cases and may need to be repeated, as Crohn's disease can re-develop, especially at the surgery site. The most common surgery isresection, in which the affected section of the bowel is removed. Following resection, the two ends of healthy bowel are attached using a surgical procedure called anastomosis. Other procedures include colectomy, which involves removing the entire colon, and a type of ostomy procedure called an ileostomy.
  • If you smoke, stop. Smoking makes Crohn’s disease more severe and makes it harder to control.


At present there is no known way to prevent Crohn’s disease. However, there are various treatments that can keep the patient symptom-free. Patients should not smoke.

When To Call A Doctor

Call a doctor if you experience symptoms of Crohn’s disease, especially lower-right abdominal

pain, which may signal appendicitis, and could be a medical emergency. Seek medical attention right away if you experience black or bloody stools, a swollen abdomen, or a fever over 101°F.

Reviewed by Jenifer K. Lehrer, M.D., Department of Gastroenterology, Aria-Torresdale Hospital, Aria Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network.