Ask the Doctor: Caroline Hwang, M.D.

Q. What is the difference between Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS)?

A. Although the two conditions sound alike and can cause similar symptoms, IBD and IBS differ greatly in many ways, including treatment strategies.

Inflammatory Bowel Disease (IBD) is a term for a group of chronic GI conditions, which include Crohn’s disease and ulcerative colitis. IBD is characterized by inflammation (ulcers and irritation) seen in the intestinal tract, which is diagnosed with a colonoscopy (flexible tubes with fiberoptic cameras to take high-definition pictures of the gastrointestinal tract). It is usually caused by an overactive immune system that attacks the bacteria in the gut, and can lead to symptoms such as pain, diarrhea, bleeding and weight loss. Uncontrolled inflammation can lead to an increased risk of hospitalizations, surgeries and colon cancer.

Irritable Bowel Syndrome (IBS) is much more common than IBD. In fact, it is estimated to affect one in five Americans. IBS is often a chronic condition that is marked by symptoms of abnormal bowel movements (can be diarrhea or constipation), bloating and abdominal pain. It differs from IBD in that there is no inflammation seen in the gastrointestinal tract, nor is there an increased risk of cancer or need for surgery. IBS may be due to alterations in the gut such as:

  • Motility: How fast or slow the gut moves
  • Microbiome: The billions of microorganisms that live in your gut
  • Gut-brain axis: Sensory communication/perception between the intestine and brain

The treatment strategies for IBD and IBS are quite different from one another. Since IBD is a condition where the immune system is over-active, many of the treatments (for moderate-severe disease) help to modulate (“cool down”) the immune system. When used consistently, these medications can help the intestinal tract to heal and lead to improved nutrition and decreased symptoms and risk of cancer. However, if patients are started on medications too late or do not respond to current treatments, surgery may be necessary to remove damaged areas of the gastrointestinal tract and improve quality of life.

Treatment of IBS is often individualized, based on the predominant type of gut alterations and symptoms a patient has. Treatment can include probiotics or antibiotics, laxatives or antidiarrheals, and medications that help decrease gut-related pain transmission to the central nervous system. In addition, non-pharmacological interventions including specific dietary changes, stress reduction, and exercise can make a large impact on the severity of symptoms.

If you are experiencing symptoms of IBD or IBS, please consult with your physician to determine the best course of treatment for you.