What are Crohn’s disease and ulcerative colitis?

Known collectively as inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis affect more than 3.1 million Americans. That’s one in every 100 Americans living with one of these debilitating, medically incurable diseases that attack the digestive system. The fastest growing patient population is children under the age of 18.

While Crohn's disease may attack anywhere along the digestive tract, from the mouth to the anus, ulcerative colitis inflames only the large intestine (colon) and rectum. Symptoms of these diseases may include abdominal pain, persistent diarrhea, rectal bleeding, debilitating fatigue, and extreme weight loss. Patients can be diagnosed at any age, but are most commonly diagnosed between the ages of 15 and 35. Many patients experience numerous hospitalizations. About 23 to 45 percent of people with ulcerative colitis and up to 75 percent of people with Crohn’s disease will eventually require surgical intervention for their disease.

Although considerable progress has been made in IBD research, investigators do not yet know what causes this disease. Studies indicate that the inflammation in IBD involves a complex interaction of factors: the genes the person has inherited, the immune system, and something in the environment. Foreign substances (antigens) in the environment may be the direct cause of the inflammation, or they may stimulate the body's defenses to produce an inflammation that continues without control. Researchers believe that once the IBD patient's immune system is "turned on," it does not know how to properly "turn off" at the right time. As a result, inflammation damages the intestine and causes the symptoms of IBD. That is why the main goal of medical therapy is to help patients regulate their immune system better.

Treatment of IBD can include medication, alterations in diet and nutrition, and  surgery. There is no standard treatment that will work for all patients. Each patient’s situation is different and treatment must be followed for each circumstance.

To learn more about these diseases, see more Foundation resources.