IBS vs IBD: What Are The Key Similarities And Differences?

What is Irritable bowel syndrome (IBS)?

IBS is defined as abdominal discomfort or pain associated with changes in bowel habits that occur at least three days per month during the previous three months.1,2 Changes in bowel habits may include symptoms predominantly related to either diarrhea or constipation, but may also include a mixed sensation that alternates between diarrhea and constipation.2

What is inflammatory bowel disease (IBD), such as Crohn’s disease, ulcerative colitis?

IBD is a chronic, relapsing, inflammatory disorder that affects the gastrointestinal tract. IBD includes Crohn’s Disease and ulcerative colitis.4 Characteristic symptoms of inflammatory bowel disease include diarrhea that has persisted for more than 2 weeks, rectal bleeding, inflammatory mass, weight loss, perianal disease, and fever.3

Similarities between IBS and IBD5,6

IBS and IBD have some features in common, such as symptoms and demographics.

  • Most commonly affects peoples under the age of 50
  • Bacterial infection may cause both IBS and IBD
  • May be caused by inflammation
  • May result from changes to the gut environment
  • Both have similar intestinal symptoms
  • Both may have an indirect effect on other bodily systems, such as the skin, bone, and joints

Differences between IBS and IBD5,6

  • IBS is more prevalent than IBD
  • IBS is typically found worldwide despite some variations in location, but IBD is more commonly found only in urban or Westernized locations
  • Females are more likely to have IBS than IBD
  • IBD may be caused by genetic factors, but a genetic factor is not clearly documented for IBS
  • IBS symptoms may be triggered by dietary or environmental factors at any time, while IBD may be more unpredictable
  • IBS is mostly managed by addressing symptoms in a less structured manner with drugs and lifestyle changes, while IBD is managed using a step-wise approach with various drugs
  • IBS is a functional bowel disorder, which means that it is characterized by symptoms that occur in the gastrointestinal tract and is not due to structural changes in the body. IBD is not a functional bowel disorder. IBD is a chronic inflammatory disease of the gut that may change the structure of the intestines, which can be diagnosed with imaging tests.

Overlap of IBS and IBD

Though unclear, there is research to suggest that people with IBD may also have IBS symptoms. Therefore, there is a possible overlap between IBS and IBD. IBS is present in approximately 59.7% of people with Crohn’s disease and 38.6% of people with ulcerative colitis who are in clinical remission. Symptoms of IBS in people with IBD may lead to more stress and further impair their quality of life.5

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Written by: Truc Thanh | Last reviewed: June 2016.