Is It IBD or IBS? How to Tell the Difference

October 05, 2022

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) may sound similar, but they are very different diagnoses. Although both are chronic disorders that share some gastrointestinal symptoms, the two conditions are very different in terms of symptoms, causes, treatments and potential complications.

What Is Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) is an autoimmune disorder that causes inflammation in the gastrointestinal tract. The two main types of IBD are Crohn’s disease and ulcerative colitis. As the name suggests, patients with ulcerative colitis have inflammation only in the colon while patients with Crohn’s disease can have inflammation anywhere along the gastrointestinal tract.

“The most common symptoms of inflammatory bowel disease are diarrhea, abdominal pain and rectal bleeding,” says University Hospitals gastroenterologist Vu Nguyen, MD. “Other symptoms may include bowel movement urgency, weight loss, poor appetite, nausea and anal pain or drainage,” he adds. Because inflammatory bowel disease can affect more than the gastrointestinal tract, people may also experience joint pain, rashes or eye redness. Symptoms are chronic and, while they can often be controlled, relapse is common.

Although the exact cause is unknown, experts believe that IBD is caused by an immune response to certain environmental triggers like a virus or bacteria, leading to inflammation of the gastrointestinal tract. Genetics and lifestyle choices like smoking may also play a role in the development of IBD. Untreated, IBD can lead to permanent damage to the gastrointestinal tract and increase the risk of colorectal cancer.

The main therapy for IBD is medication to suppress specific pathways of the immune system to decrease inflammation in the gut. Your doctor will determine which medication is most appropriate for you. You may also be advised to make certain changes to your diet.

What Is Irritable Bowel Syndrome?

Irritable bowel syndrome (IBS) is a disorder of the gastrointestinal tract characterized by chronic abdominal pain with constipation and/or diarrhea. The abdominal pain is often relieved when the bowels are emptied.

Although the exact cause of irritable bowel syndrome is unknown, experts believe there is a brain-gut connection since patients often experience worsening symptoms during times of stress. Other potential causes may include:

An imbalance of good and bad bacteria in the GI tract
Unusual permeability of the intestinal walls (leaky gut syndrome)
An immune response to food sensitivities

“The first step in managing patients with irritable bowel syndrome is to provide reassurance and education around stress-reduction techniques,” says Dr. Nguyen. “Although IBS can cause significant gastrointestinal symptoms, unlike IBD, it does not lead to permanent damage of the gastrointestinal tract or increase the risk for colorectal cancer.”

Treatment for IBS is primarily aimed at relieving symptoms. Medications may include:

Anti-spasmodic medications to help relieve abdominal spasms
Laxatives for constipation
Anti-diarrheal medications
Soluble fiber supplements such as Metamucil and BeneFiber
Anti-depressants may be prescribed to decrease nerve hypersensitivity and relieve abdominal pain

In addition to medication, your doctor may advise you to avoid certain foods that contain hard-to-digest sugars, including:

Some vegetables such as asparagus, broccoli, beans, garlic and onion
Some wheat products such as crackers and cereal
Certain fruits such as apples, avocados, pears and peaches
Artificial sweeteners

How Do Doctors Diagnose IBD and IBS?

Patients with persistent gastrointestinal symptoms should see their primary care doctor or a gastroenterologist so that an accurate diagnosis can be made and the appropriate treatment plan developed.

An important first step in the diagnostic process will be to take a comprehensive medical and family history. “There are certain signs and symptoms that can help distinguish IBD from IBS,” says Dr. Nguyen. “For example, patients with significant rectal bleeding, anemia or unintentional weight loss are more likely to have IBD. Also, patients with a family history of IBD are at increased risk for the disease.”

In addition, the following diagnostic tests may be performed:

Stool tests to look for inflammatory markers associated with gut inflammation, a primary characteristic of inflammatory bowel disease. These tests are up to 90 percent accurate in ruling out irritable bowel syndrome.
Imaging tests and/or colonoscopy to look for inflammation