Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) affect the large intestine and can cause abdominal discomfort and diarrhea. However, IBD is an autoimmune condition, while IBS refers to a collection of chronic symptoms.

While the symptoms of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) can be similar, these conditions have different causes, methods of diagnosis, and treatments.

In this article, we look at the symptoms, diagnosis, and treatment of IBD and IBS, as well as the outlook for people with these conditions.

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IBD causes inflammation of the gastrointestinal tract, which begins at the mouth and extends through the stomach and intestines to the anus. IBD is a long-term condition with no cure.

The two main types of IBD are ulcerative colitis and Crohn’s disease.

Crohn’s disease can affect any part of the gastrointestinal tract. However, this type of IBD most commonly affects the small intestine and the start of the large intestine. Crohn’s disease can cause patches of inflammation that damage multiple layers of the wall of the gastrointestinal tract.

Ulcerative colitis primarily causes inflammation of the colon. Unlike Crohn’s disease, it causes continuous areas of inflammation. These only affect the innermost layer of the colon wall.

Crohn’s disease is typically more severe than ulcerative colitis but is less common.

Research has not yet confirmed what causes IBD, but it typically occurs due to a problem with the immune system. IBD can run in families. Certain lifestyle factors, such as smoking, can also increase the risk of developing IBD.

Common symptoms of IBD include:

  • diarrhea
  • bloody stools and rectal bleeding
  • sudden urges to have a bowel movement
  • abdominal pain and cramping
  • a sense of the bowels not being empty after a bowel movement
  • unintended weight loss

Other symptoms may include:

Symptoms can vary considerably from person to person, depending on the location and severity of the inflammation. Symptoms also tend to come and go in cycles. People will experience flares where symptoms suddenly worsen, and periods of remission during which they have few, or no symptoms.

To diagnose IBD, a doctor will typically start by taking a medical history and performing an initial physical exam. They will then order one or more of the following tests to aid their diagnosis:

  • Endoscopy: An endoscopy is a primary method of diagnosing Crohn’s disease. This procedure involves inserting an endoscope, a thin tube with a light and camera on it, down a person’s throat into their gastrointestinal tract.
  • Colonoscopy: This test requires the insertion of an endoscope through a person’s anus into their rectum and colon. A doctor will use this to diagnose ulcerative colitis.
  • X-ray or CT scan: These create an image of the inside of the body and allow a doctor to check for signs of any other problems.
  • Blood tests: A healthcare professional can analyze a small sample of a person’s blood to look for signs of inflammation and rule out other conditions.
  • Stool tests: These require the individual to provide a sample of their stool for analysis. Doctors use stool tests to rule out other conditions.

There is no cure for IBD, so doctors will use treatments to relieve symptoms, prevent flare-ups, and maintain periods of remission. The treatments that they choose will depend on the severity of the symptoms.

Different medications are available for IBD, including:

  • Aminosalicylates: These help reduce inflammation. Doctors often prescribe these drugs to people with mild symptoms.
  • Immunomodulators: Immunomodulators work by suppressing immune-system activity and reducing inflammation. These can treat mild to moderate IBD.
  • Biologics: Doctors tend to prescribe these drugs when other treatments have not worked. Biologics target specific parts of the immune system to reduce inflammation.

Some people may need surgery to remove or bypass damaged parts of their gastrointestinal tract. However, surgery for IBD is becoming less common.

IBD is a lifelong condition for which there is currently no cure. Symptoms tend to come and go in cycles of flares and remission.

Treatment for IBD typically focuses on relieving a person’s symptoms and trying to induce and maintain remission.

Irritable bowel syndromeInflammatory bowel disease
What it isA range of symptoms linked to digestive issues and increased gut sensitivity.Inflammatory diseases of the bowel, including Crohn’s disease and ulcerative colitis.
SymptomsAbdominal pain and cramping, sensations of incomplete bowel evacuation, gas and bloating, and mucus in the stool.Abdominal pain and cramping, sensations of incomplete bowel evacuation, bloody stools, diarrhea, and unintended weight loss.
Diagnosis methodA doctor will assess a patient’s symptoms and review their medical history. Symptoms lasting for more than 6 months and occurring at least once a week indicate IBS.To determine which disease is causing symptoms, a medical professional may carry out an endoscopy or colonoscopy and take blood and stool samples.
TreatmentA person with IBS may be able to manage the condition by making lifestyle changes and diet modifications. A doctor may also prescribe laxatives or anti-diarrheal drugs.A doctor will recommend anti-inflammatory medication, including aminosalicylates, immunomodulators, and biologics. In severe cases, surgery may be necessary.

IBS is a long-term condition that affects the intestines. It causes a group of digestive symptoms that typically occur together. Unlike IBD, IBS does not cause any visible signs of damage or inflammation in the gastrointestinal tract.

IBS is a common condition and affects around 12% of people in North America and 7-21% of people globally. It is more common in women than in men and is more likely to develop in people under the age of 50.

It is unclear what specifically causes IBS, but doctors believe that digestive problems and increased gut sensitivity may play a role. Stressful life events and mental health issues, such as depression and anxiety, may also increase a person’s risk of developing IBS. It is possible that the condition may run in families.

As with IBD, the symptoms of IBS tend to come and go in cycles. Some females with IBS may experience more symptoms during their period.

IBS usually involves sudden changes in bowel habits, such as diarrhea or constipation. The symptoms can vary from mild to severe and may include:

  • abdominal pain and cramping
  • gas and bloating
  • a sensation of incomplete bowel evacuation
  • mucus in the stool

To diagnose IBS, a doctor will review a patient’s family and medical history and assess the frequency and severity of their symptoms.

A doctor will confirm an IBS diagnosis if a person’s symptoms started more than 6 months prior, and they experience symptoms at least once a week.

There are no specific tests for IBS. However, to rule out other conditions, a doctor may order:

Treatment for IBS typically involves making dietary and lifestyle changes. A doctor may recommend:

  • eating more fiber
  • avoiding foods that contain gluten
  • following a specific IBS-friendly diet
  • exercising regularly
  • reducing and managing stress
  • getting adequate sleep

A doctor may also recommend or prescribe medications to treat specific symptoms of IBS. These may include:

  • anti-diarrheal drugs, such as loperamide (Imodium)
  • laxatives or fiber supplements for constipation
  • antispasmodics to help reduce abdominal pain and cramping
  • antidepressants, which can also help treat abdominal pain and cramping

There is currently no cure for IBS, and a person may find that their symptoms change over time. It is usually possible to manage IBS by making lifestyle and dietary changes. Keeping a symptom diary to identify and avoid triggers, such as stressors or certain foods, can help reduce flares.

A doctor can also prescribe medications to relieve specific symptoms and provide tailored dietary advice to help minimize discomfort.

IBD and IBS are both long-term conditions that can cause similar symptoms, such as abdominal pain and changes in bowel habits.

The symptoms of both IBD and IBS tend to come and go, alternating between flare-ups and periods of remission. However, these two conditions have different causes and treatments.

IBD, which includes Crohn’s disease and ulcerative colitis, is an autoimmune condition that causes inflammation of the gastrointestinal tract. IBS seems to result from digestive problems and increased gut sensitivity.

There is no cure for either condition, and treatment will primarily focus on managing symptoms. Medications can reduce gut inflammation in people with IBD, while IBS treatment focuses primarily on lifestyle and dietary changes.