context: Crohn's disease is a chronic, or long-term, illness. With Crohn's disease, the intestine, or bowel, becomes inflamed and ulcerated, or marked with sores. Along with ulcerative colitis, Crohn's disease is one of a group of diseases known as inflammatory bowel disease ( IBD). Crohn's disease usually affects the lower part of the small intestine, which is called the ileum. It can, though, occur in any part of the large or small intestine, stomach, or esophagus. It can even occur in the mouth. Crohn's disease can happen at any age. It's most common, though, in people who are between the ages of 15 and 30. Children and teens with Crohn's disease face unique challenges. Crohn's disease can stunt growth, weaken bones, and delay puberty. Crohn's disease can disrupt the normal function of the bowel in a number of ways. The bowel tissue may: Swell, thicken, or form a stricture (scar tissue), leading to an obstruction (blockage) of the passageway inside the bowel Develop ulcers in the deep layers of the bowel wall Lose its ability to absorb nutrients from digested foods (malabsorption), especially in the ileum where vitamin B12 and bile acids are absorbed Develop abnormal passageways (fistulas) from one part of the bowel to another or from the bowel to nearby tissues The symptoms of Crohn's disease depend on where the disease occurs in the bowel. They also depend on its severity. In general, symptoms can include: Chronic diarrhea with or without blood in the stool Rectal bleeding Weight loss Fever Abdominal tenderness Feeling of mass or fullness in the lower right abdomen Fatigue Children and teens with Crohn's disease have periods of severe symptoms followed by periods of no symptoms. The period with no symptoms is called remission, and it can last for weeks or years. Anti-inflammatory medications or dietary changes may lead to remission, but there is no way to know when a remission will occur or when symptoms will return. Other symptoms can develop, depending on complications related to the disease. For instance, a person with a fistula -- abnormal passageway -- in the rectal area may have pain and discharge around the rectum. Other complications from Crohn's disease include: Arthritis Gallstones Kidney stones Inflammation (swelling) of the eyes and mouth Liver disease Skin rashes or ulcers Anemia The cause of Crohn's disease is not known. It is likely that Crohn's is an inherited disease that causes an abnormal response of the immune system in the gastrointestinal tract. People who have a relative with Crohn's disease are more likely to develop the disease themselves. People of Jewish ancestry also have a greater risk for the condition. Still, the risk of getting Crohn's disease is low. The doctor will review the patient's medical and family history. Various tests are used to diagnose Crohn's disease, including the following: Endoscopy (such as colonoscopy or sigmoidoscopy): During this procedure, a doctor inserts a flexible, lighted tube with a camera in the rectum. The tube and camera together are called an endoscope. It's used to view the inside of the rectum and colon. Colonoscopy shows a greater portion of the colon than sigmoidoscopy does. A small sample of tissue may be taken for testing, or biopsy. Blood tests: When testing the blood, the doctor will look for signs of anemia, or a high white blood cell count. A high white blood cell count indicates inflammation or infection somewhere in the body. The doctor will also perform tests to look for and identify inflammatory markers. Barium X-ray (barium enema or small bowel series): These procedures use X-rays to examine the upper or lower intestine. Barium coats the lining of the small intestine and colon and appears white on an X-ray. This allows the doctor to review any abnormalities. Treatment of Crohn's disease depends on how severe it is and where it's located. The disease can sometimes go into remission on its own. So it's not always possible to determine whether a specific treatment has been effective. When Crohn's disease is active, treatment is aimed at controlling inflammation, correcting nutritional deficiencies, and relieving symptoms such as pain, diarrhea, and fever. In general, medications are the first step in treating Crohn's disease in children and teens. Some of these drugs include anti-inflammatories, antibiotics, antidiarrheals, and immune-suppressing drugs (including corticosteroids). Medications called biologics are also used to treat Crohn's. They are called biologics because the drugs are formulated from proteins found in the human body's immune system. The proteins are genetically modified and processed to be used as treatment. Biologics, which are given as an injection or IV infusion, are designed to interfere with the inflammatory processes that are the hallmark of Crohn's disease. For those patients who have nutritional deficiencies, supplements are often prescribed. There are also some studies researching dietary modification including an all liquid diet. Sometimes, drugs cannot keep Crohn's disease under control. In those cases, surgery to remove a part of the bowel is sometimes needed. The disease, though, often returns to the area near where the inflamed part was removed. A healthy lifestyle is important in managing Crohn's. Children and teens should exercise regularly and eat a healthy diet. People with this disease usually are able to lead a healthy and active life. Most children with Crohn's are able to attend school and participate in sports and daily activities if the disease is treated and managed properly.