Medically reviewed by Joseph Runde, DO, Division of Gastroenterology 

Among non-medical professionals, inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are often mistaken for one another, and their differences tend to be unknown, due to the similarity in their names and acronyms. The reality is that while both conditions present symptoms such as pain and change in stool pattern, the severity of and complications for each are vastly different.  

How common are IBD and IBS?

Inflammatory bowel disease impacts approximately 1 in every 200-250 people. Irritable bowel disease affects about 1 in every 10-20 people.

How do these two conditions differ?

IBD and IBS are both gastrointestinal (GI) disorders but differ in terms of symptoms, causes, treatments and potential complications.

IBD is an umbrella term for two main diagnoses: Crohn’s disease and ulcerative colitis. In both conditions, we see damage (or inflammation) in the intestine caused by a person’s own immune system. Patients with ulcerative colitis primarily have inflammation in the colon (or large intestine) while patients with Crohn’s disease can have inflammation anywhere along the gastrointestinal tract. IBD is a chronic condition, meaning that inflammation is ongoing and must be controlled with long-term therapy. IBD can result in bleeding, fever, elevation of the white blood cell count, as well as diarrhea and cramping abdominal pain. An important clue about IBD in children can also be poor growth. 

IBS, sometimes better described as “functional gastrointestinal disorder” in children, might result in crampy abdominal pain, nausea, vomiting, diarrhea, and/or constipation. It may be driven in part by abnormal function of the intestine or by increased nervous system response, but we do not expect to find inflammation.

What are the symptoms of IBD vs. IBS?

Crohn's disease, sometimes described as ileitis or enteritis, is a form of IBD that can involve deep (transmural) inflammation in any portion of the GI tract including the esophagus, stomach, large intestine and small intestine (ileum).

Ulcerative colitis, the other most common form of IBD, involves a more superficial (less deep into tissue) inflammation in the large intestine (or colon, which includes the rectum). The inflammation begins in the rectum and extends continuous into the colon, sometimes involving the entire colon, which is called pancolitis.

A special consideration in children is “very early onset” IBD, which includes children diagnosed with IBD less 6 years old. This group of children requires special consideration for links to immune deficiency and single gene defects that can result in inflammation to the intestine. At Lurie Children’s, these children are often co-managed with our Immunology team.

The most common symptoms of IBD (Crohn’s or ulcerative colitis) include:

  • Abdominal pain (sometimes in lower right area)
  • Diarrhea, with or without blood
  • Urgency to use restroom
  • Rectal bleeding
  • Anemia
  • Fatigue
  • Weight loss
  • Failure to grow

Sometimes children with IBD – Crohn’s or ulcerative colitis also experience symptoms outside of their GI tract (extra-intestinal inflammation):

  • Skin lesions (rash)
  • Joint pain or swelling
  • Inflammation of the eyes
  • Ulcers in mouth or around bottom
  • Liver disorders
  • Osteoporosis
  • Anemia

IBS/functional gastrointestinal disorder symptoms often include:

  • Abdominal pain/ cramping
  • Bloating
  • Gas (flatulence)
  • Nausea, vomiting
  • Changes in bowel movement habits; these changes may be towards constipation (hard stool), diarrhea (soft or fluid stool), or alternating between the two
  • Urgency to use restroom after eating

How is IBD diagnosed vs. IBS?

Diagnosing IBD is a process, and while it may take some time to complete initial screening tests, an endoscopy, colonoscopy, and biopsy are the standards of care, if IBD is highly suspected, to make the diagnosis and to personalize a treatment plan.  

In addition to a complete medical history and physical examination, the diagnostic approach for Crohn's disease and ulcerative colitis includes:

  • Blood tests
  • Stool infection testing and stool inflammation testing (calprotectin)
  • Endoscopy and colonoscopy with biopsies
  • Radiographic imaging such as ultrasound, MRI and/or Upper gastrointestinal (GI) series with small bowel follow through — examination of the esophagus, stomach, and duodenum, often by drinking liquid barium.

In contrast, there is not a blood test, stool test or scope that confirms a diagnosis of IBS. This diagnosis is made based on history, physical examination, and response to supportive strategies. While evaluation may result as reassuring, this does NOT mean that the symptoms are not real; rather that our testing has limitations.

How is IBD treated vs. IBS?

With IBD, the treatment is personalized based on presentation, complications and severity and extent of inflammation. Your care team might explore different interventions such as long-term medical therapy, dietary therapy, or surgical therapy to help get existing inflammation quiet and subsequently keep it quiet if possible. Our approach has become more proactive overtime as a result of compelling data suggesting better therapy upfront can help minimize complications in the future and advances in medical therapy options (advanced therapeutics including “biologic” and “small molecule” agents). It’s important to be proactive as uncontrolled inflammation for long periods of time can result in complications such as abscess, fistula (abnormal connections between intestine/skin), stenosis (narrowing), stricture (scar tissue), or need for surgical intervention.

IBS management, on the other hand, is focused on supportive strategies such as lifestyle changes with routine, regular physical activity, dietary changes or restrictions, sleep hygiene, therapy such as cognitive behavioral therapy (CBT) and sometimes medications which can help with stomach relaxation, decreased intestinal spasm and others.

In both cases, helping your child feel better is the goal. The sooner IBD or IBS is evaluated and diagnosed, the sooner we can take the next steps in getting them back to their baseline. Gastrointestinal disorders are unique to each person, so it’s advised not to compare one child’s experience to another and to seek a gastroenterologist’s perspective as soon as concerning symptoms present.

Learn more about our Division of Gastroenterology

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