What is inflammatory bowel disease (IBD)?

Inflammatory bowel disease (IBD) is a term for two conditions (Crohn’s disease and ulcerative colitis) that are characterized by chronic inflammation of the gastrointestinal (GI) tract. Prolonged inflammation results in damage to the GI tract. Some of the differences between Crohn’s disease and ulcerative colitis:

Crohn’s Disease

  • Can affect any part of the GI tract (from the mouth to the anus)—Most often it affects the portion of the small intestine before the large intestine/colon.
  • Damaged areas appear in patches that are next to areas of healthy tissue
  • Inflammation may reach through the multiple layers of the walls of the GI tract

Ulcerative Colitis

  • Occurs in the large intestine (colon) and the rectum
  • Damaged areas are continuous (not patchy) – usually starting at the rectum and spreading further into the colon
  • Inflammation is present only in the innermost layer of the lining of the colon

What are the symptoms of IBD?

Some common symptoms are:

  • Persistent diarrhea
  • Abdominal pain
  • Rectal bleeding/bloody stools
  • Weight loss
  • Fatigue

What causes IBD?

The exact cause of IBD is unknown, but IBD is the result of a defective immune system. A properly functioning immune system attacks foreign organisms, such as viruses and bacteria, to protect the body. In IBD, the immune system responds incorrectly to environmental triggers, which causes inflammation of the gastrointestinal tract. There also appears to be a genetic component—someone with a family history of IBD is more likely to develop this inappropriate immune response.

How is IBD diagnosed?

IBD is diagnosed using a combination of endoscopy (for Crohn’s disease) or colonoscopy (for ulcerative colitis) and imaging studies, such as contrast radiography, magnetic resonance imaging (MRI), or computed tomography (CT). Physicians may also check stool samples to make sure symptoms are not being caused by an infection or run blood tests to help confirm the diagnosis.

How is IBD treated?

Several types of medications may be used to treat IBD: aminosalicylates, corticosteroids (such as prednisone), immunomodulators, and the newest class approved for IBD—the “biologics”. Several vaccinations for patients with IBD are recommended to prevent infections. Severe IBD may require surgery to remove damaged portions of the gastrointestinal tract, but advances in treatment with medications mean that surgery is less common than it was a few decades ago. Since Crohn’s disease and ulcerative colitis affect different parts of the GI tract, the surgical procedures are different for the two conditions.

This post was originally published by Centers for Disease Control and Prevention. It is republished with permission.

Last Reviewed: March 26, 2018