IBD vs. IBS: What's the Difference?

Irritable bowel syndrome, leaky gut, functional gut disorder. It seems like everyone has some sort of stomach issue these days -- and it's not unreasonable to think so, considering the quality of the average American diet. 

Two common digestive disorders, irritable bowel syndrome and inflammatory bowel disease, have some symptoms in common and people often use the terms interchangeably. IBD and IBS are not one and the same, though: The underlying causes differ, as do the diagnostic processes and treatments. 

This guide breaks down the differences between IBD and IBS, from definition to diagnosis to treatment options. 

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What is inflammatory bowel disease?

IBD is an umbrella term that covers inflammation-related digestive diseases. The two types of IBD, Crohn's disease and ulcerative colitis, both involve chronic inflammation and usually involve severe symptoms, including diarrhea, chronic fatigue, weight loss and abdominal pain or cramping. 

Crohn's disease occurs when the lining of your digestive tract becomes inflamed. This type of inflammation can often spread to deep layers of body tissue and can cause debilitating pain in severe cases. Crohn's can affect different parts of the digestive tract in different people.

Ulcerative colitis is localized to the colon, or large intestine -- "colitis" means inflammation of the colon. In people with this disease, the lining of the colon becomes inflamed and sores, or ulcers, develop. Like Crohn's disease, ulcerative colitis can cause serious abdominal pain. 

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What is irritable bowel syndrome?

IBS is actually not classified as a disease, but instead a "functional disorder" or a syndrome, which is defined as a group of symptoms that occur together. Those symptoms are abdominal pain, cramping, bloating, diarrhea or constipation (or both, alternating) and gas. 

IBS is considered a chronic symptom that requires lifelong management, although only a small percentage of patients with IBS have severe symptoms, according to the Mayo Clinic. 

Despite being a relatively common condition (up to 12% of US adults may have IBS), the National Institute of Diabetes and Digestive and Kidney Diseases reports that doctors and scientists don't yet know what causes this syndrome. 

There's some debate -- both in the medical community and throughout the general public -- that IBS isn't real. IBS has been called a psychological disorder in the past, because people with IBS don't show physiological signs of disease when doctors perform exams or take images of their digestive tracts. 

It's true that IBS has been associated with anxiety and depression -- 50 to 90% of IBS cases may coexist with a psychological condition, with depression being the most common association. However, no cause-and-effect relationship has been found, and there's a typical chicken-and-egg conundrum at play: It's not clear whether IBS causes psychiatric disorders or psychiatric disorders cause IBS (or if there's direct causation at all). 

IBD vs. IBS: The major differences

Again, although the two acronyms are often confused or used interchangeably, IBD and IBS are two very different conditions -- here's a rundown of the major differences between the two.

IBD vs. IBS: Similarities

Though IBD and IBS have many distinctions, they do share some similarities. Some symptoms overlap, for example: People with IBD and IBS may both experience abdominal pain and cramping, diarrhea, nausea or vomiting. Both conditions can also make people feel like they urgently need to use the restroom, even if they actually don't. 

Stress is also known to aggravate the symptoms of both IBD and IBS, so either condition can benefit from practicing stress-reduction techniques. Dietary changes may also help people with IBD and IBS, though specific dietary recommendations differ. 

If you have either condition, you should work with your doctor, a gastroenterologist or a registered dietitian who specializes in digestive disorders to find a diet and treatment plan that helps quiet your symptoms. 

Diagnosing IBD and IBS

One of the major differences between these two conditions is that IBD shows clinical signs of disease when patients undergo an exam and imaging, while IBS does not show signs of distress in the digestive tract. That's a big part of the reason that IBS is classified as a syndrome and not a disease. 

Doctors diagnose IBD through a series of tests and images, including colonoscopies and endoscopies, to check for inflammation in your esophagus, stomach, small intestine and large intestine. The specific tests a patient undergoes may depend on their symptoms and medical history. Doctors also use x-rays, computerized tomography (CT) scan and magnetic resonance imaging (MRI) to get visuals of any inflammation in your digestive tract. 

For IBS, on the other hand, there is no specific testing procedure to get a diagnosis. Doctors usually diagnose IBS through a series of questions about your symptoms and take into account your health and medical history. Keep in mind that IBS is somewhat a diagnosis of exclusion, so your doctor may recommend tests or imaging to rule out other, potentially more dangerous, conditions that share symptoms with IBS. 

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If you think you have IBD or IBS

Schedule an appointment with your doctor to discuss your symptoms if you think you have IBD or IBS. The only way to truly find out if you have one of these conditions (or something else) is to undergo a medical exam and imaging tests. Your primary care doctor may refer you to a specialist, such as a gastroenterologist, if your symptoms are severe. 

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