Inflammatory bowel disease (IBD) is chronic inflammation of the digestive tract. Its cause is unknown. It appears to develop due to an overactive immune system that continues to attack healthy tissue after first being stimulated to fight a harmful substance. In patients with IBD, tissue lining the mouth, stomach, esophagus, intestines or anus can become red, swollen and bleed. Abdominal pain, cramping and bloody diarrhea are common IBD symptoms.

The two primary types of IBD are Crohn's disease (CD) and ulcerative colitis (UC). CD can occur anywhere along the digestive tract (most commonly in the small and/or large intestine), and irritate all layers of tissue in the wall lining. UC occurs only in the large intestine, usually starting in the rectum, and affects only the inner intestinal lining (colon mucosa).

Once it appears, IBD is a lifelong disease. It occurs primarily in the United States and Europe and among young people (10 to 35 years old) more often than in the elderly. Whites are at greater risk for IBD than non-whites, and people with Jewish ethnic backgrounds have a higher risk than non-Jews. Men and women appear to be at equal risk of developing IBD. Cigarette smokers are at higher risk of developing CD (but not UC). IBD also appears to run in families.

An initial physical examination may include a medical history, blood tests and stool tests. There are two primary methods used to diagnosis IBD. A barium x-ray involves ingesting a chalky liquid that helps organs show up clearly on x-rays. This can be used for examination of the upper digestive tract. The examination of the lower tract involves a barium enema or administration of the barium via a tube in the rectum. A colonoscopy involves inserting a small, flexible tube through the anus and into the colon. A light and camera record images for analysis by a physician. Biopsies and color photos can be taken during this procedure.

Complications of IBD include anemia (too few red blood cells), intestinal blockage or abscesses and an increased risk of colon cancer.

Long-term treatment is often required for patients with IBD. Medications such as aminosalicylates, corticosteroids and immunosuppressive therapy can help keep the symptoms of IBD in remission. Hospitalization may be required to treat patients with IBD who are severely malnourished, dehydrated or have experienced massive blood loss. Surgery may be necessary to treat cancer, when intestinal obstructions or perforations exist, or when medicines fail to work.

IBD is different from irritable bowel syndrome (IBS), which cannot be visually detected on diagnostic tests and does not include the symptoms of rectal bleeding, fever and elevated white blood cell count seen in patients with IBD.