Colitis and irritable bowel syndrome (IBS) are separate conditions that both affect the gut. A person may develop both, but they require different treatments as the drugs for colitis will not successfully treat IBS. Some symptoms may appear similar, and both are likely lifelong conditions.

The similarity of the abbreviations IBS (irritable bowel syndrome) and IBD (irritable bowel disease) may sometimes cause misunderstanding.

This article will look at colitis and IBS and how they differ in their symptoms, diagnosis, and treatment.

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Both colitis and IBS affect the gut and can result in diarrhea and abdominal pain.

Colitis or IBS are both conditions that can affect people of any age, but symptoms may be more severe in younger people.

The International Foundation for Gastrointestinal Disorders suggests that IBS is the most common digestive tract disorder, with 10–15% of people living with the condition.

The Centers for Disease Control and Prevention (CDC) estimate that around 3 million adults in the United States had an IBD diagnosis in 2015.

Colitis and IBS can produce similar symptoms that may include the following:

IBS symptomsColitis symptoms
abdominal painabdominal pain
stomach crampsstomach cramps
bloatingwatery stools with blood, pus, or mucus present
white mucus in stoolsrectal bleeding
a feeling of incomplete bowel movementsurgent need for bowel movements with no stools produced
IBS may also link to constipation, diarrhea, or both

A person living with IBS does not typically experience rectal bleeding		A person who has a more severe form of colitis may also experience fever, fatigue, vomiting or nausea, or weight loss

Similarities between colitis and IBS include:

  • the condition can become chronic
  • symptoms may progress and become more severe
  • poor quality of life when symptoms flare
  • feeling that the abdomen is bloated
  • a person may develop psychological disorders

Differences between the two include:

  • Colitis is a whole-body disease, while IBS is a syndrome that mainly affects the gut.
  • Doctors do not yet know the triggers of colitis, although certain foods may be suspect. IBS may include triggers such as stress or particular food groups.
  • Colitis results in physical damage to the colon, while IBS does not.
  • Colitis increases the risk of colon cancer, while IBS does not.
  • A person may develop IBS symptoms alongside colitis, although this is rare.
  • A person can develop another disorder alongside IBS, which may make the condition more severe. Conditions include fibromyalgia, chronic fatigue syndrome, and chronic pelvic pain.
  • With colitis, a person may develop anemia, malabsorption, liver complaint (primary sclerosing cholangitis), inflammation of the eye (uveitis), or inflammation of fat under the skin leading to nodules (erythema nodosum).
  • With IBS, a person may develop digestive conditions, including dyspepsia and gastroesophageal reflux disease (GERD).

Abdominal pain is a symptom of both IBS and colitis.

A person with IBS may experience stomach cramps, pain, and discomfort. They can relieve the pain by going to the bathroom and having a bowel movement. They may also feel bloated and have a lot of stomach gas.

A person with colitis also experiences abdominal pain, but this is due to gut inflammation. The pain could be from:

  • Narrowed intestines (intestinal strictures): These are blockages or obstructions, making it difficult for food to pass.
  • Fistulas: Some pain may be a result of ulcers or sores on the inside of the intestine wall. These may link and cause pain in other parts of the body, including a person’s bladder, vagina, or skin.
  • Bacteria: Too many bacteria in the small intestine could lead to gas, bloating, or cramps.
  • Poorly digested food: This may cause too much gas and discomfort in the abdomen.

A person with colitis may also experience IBS symptoms.

A healthcare professional will use the following to diagnose IBS:

  • medical history, including family and close relative medical history
  • physical examination
  • diagnostic testing, such as collecting a stool sample

Diagnosis for colitis is typically the same. It will begin with a medical history as well as a physical examination. A person may consider sharing previous lab results or a summary of previous visits to a healthcare professional.

A person may undergo further testing of their stool samples and blood, and when a doctor has the results from these tests, they may request more detailed investigations of the intestines. These investigations may include:

  • Colonoscopy: This involves inserting a small camera through the anus with sedation. It enables the healthcare professional to examine the length of the colon.
  • Sigmoidoscopy: This examines the left side of the colon or rectum. It enables the healthcare professional to diagnose ulcerative colitis. Individuals may not require sedation because the procedure can offer less discomfort than other endoscopies.
  • Biopsy: A doctor will take small pieces of tissue during an endoscopy for analysis or screening.
  • Scans, including barium contrast studies: A person will drink a barium solution that will highlight intestinal features during an X-ray or cross-sectional imaging that combines CT and MRI scans.

IBS and colitis could both present as colon cancer, and a doctor will be able to rule this out.

Neither IBS nor colitis has a definitive cause.

Colitis causes

Possible reasons for a person developing colitis may include:

Geographical location

A study on the global burden of disease examined IBD and found that between 1990 and 2017, the worldwide number of people living with IBD increased, particularly in newly industrialized countries.

Defective immunity

A 2018 study looking at T-cells — part of the body’s immunity against foreign invaders — found that they play an important role in IBD.

Genetics

A 34-year population study in Denmark found that the risk of developing IBD increased for up to third-degree relatives, which may include first cousins, great-grandparents, and great-grandchildren.

Gut biomes, including a mix of bacteria, virus, and fungi cells

According to a 2018 study, an increase in bacteria and a decrease in protective bacteria in the gut biome may influence the development of IBD. People living with IBD were also more likely to have a decrease in gut biome diversity.

Diet

A 2017 study examined the views of people living with IBD and clinicians, including gastroenterologists, dietitians, and surgeons, on the role of diet in IBD.

Many individuals living with the condition agreed that their diet affected their IBD, and more than half felt that their medical professional did not agree that diet was important.

Gastroenterologists were more likely to recognize diet as having a role in the condition, and most of them reported giving dietary advice.

IBS causes

The Crohn’s and Colitis Foundation suggests IBS does not have a lot of similarities with colitis when it comes to causes. The causes of IBS may include:

Food

Often the first help for a person living with IBS is dietary advice, as food could be part of the cause of the condition.

A 2017 study linked the condition to alcohol, caffeine, and spicy food, including red chili. Advice includes reducing the consumption of fatty foods and taking care with dietary fiber.

If a person has lactose intolerance and also avoids dairy, they should consider other ways to include calcium in their diet.

The study also pointed to a lack of evidence on whether gluten may worsen IBS symptoms.

Activity

A 2018 study found a link between IBS and adults who do not regularly exercise.

Diet

A 2017 study suggested a person should follow a regular meal pattern without skipping meals. They should not eat large portions at mealtimes and ensure that they sit down, eat slowly, and chew food carefully.

Gut microbiome

A 2019 study in Frontiers in Microbiology found links between inflammation in the gut and IBS. The inflammation could be the result of infection, stress, or a problem with gut function.

Brain-gut coordination

Frontiers in Microbiology also cited a connection between the gut and brain, suggesting that anxiety and depression could have links to IBS. It said the brain is responsible for IBS symptoms that involve the hypersensitive nerves in the intestines, with stress being a large influence on the communication between the gut and brain.

Medications

A 2018 study links antibiotics with an increased risk of developing IBS after up to 4 months of treatment.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), treatment for IBS depends on the type of IBS that a person is living with.

If a person lives with IBS and has accompanying diarrhea, a healthcare professional may ask them to eat more fiber or avoid gluten. They may also advise them to do more physical activity, reduce their exposure to stress as much as possible, and ensure they get enough sleep.

A doctor may advise a person living with IBS and constipation to eat more soluble fiber. However, insoluble fiber, such as bran, will not help the condition. They may also advise a person to increase physical activity.

People widely use laxatives to treat constipation.

The NIDDK suggests that treatment for colitis will involve medication to help reduce inflammation.

Medication for colitis may include:

  • aminosalicylates which are well proven to treat mild or moderate colitis
  • steroids, which a person may use for the short term
  • immunosuppressants
  • biologics or biosimilars

Natural remedies include:

  • Yoga: A 2015 study suggests that yoga could reduce stress and act as a remedial therapy for IBS. According to a study in Frontiers in Psychology, yoga may help people living with colitis by providing relief from depression and anxiety, which could help with the overall condition.
  • Mindfulness: A 2018 study shows that mindfulness helps reduce stress, which may also reduce IBS symptoms.
  • Diet: A 2017 study in BMJ Open Gastroenterology found that blood tests could pinpoint foods that may activate people’s IBS. The short trial found that this method could help a person remove trigger foods from their diet. Most people living with colitis will also focus on diet, but a 2019 study in Nutrients suggested that future trials will provide more evidence of specific foods that may enable symptoms to go into remission.
  • Herbal medicine: A study in 2016 examined the effects of different herbal medicines on IBS. Herbal preparations included aloe vera, artichoke, turmeric, and psyllium, a dietary fiber. Some herbal preparations may help in the treatment of colitis. According to a 2019 study from Phytotherapy Research, Chinese herbal medicines including turmeric or curcumin, Fufangkushen colon-coated capsule, and Xilei may also help.
  • Acupuncture: Another 2019 study found that acupuncture may improve IBS symptoms, but doctors need further trials to validate the results. A person may try acupuncture if they find other remedies are ineffective. Combining acupuncture with conventional medication could effectively treat colitis symptoms when compared to conventional medication alone, according to a 2020 study.

Both IBS and colitis can affect a person’s quality of life and mental health. A person may undergo personalized treatment for both their mental and physical health.

A person living with IBS may find their treatment depends on the type of IBS. Symptoms can go into remission if a person improves their diet and reduces their stress.

Those living with colitis may find symptoms progress over time. Medication can become less effective, and a person may need surgery to manage symptoms and help them go into remission.

IBS and colitis are two different conditions. IBS is a syndrome that may have unpleasant symptoms, but the condition does not damage the colon and a person can typically manage their symptoms.

Colitis may be part of an IBD diagnosis. Individuals can manage colitis with conventional medication, natural remedies, or both. They may need surgery to relieve symptoms as the condition progresses.