Irritable Bowel Syndrome (IBS) vs Irritable Bowel Disease (IBD)
Digestive conditions can cause serious symptoms like diarrhoea, constipation, abdominal pain, or bloating, which can interfere with your daily life. Although they share some symptoms, there is a significant difference between irritable bowel disease (IBD) and irritable bowel syndrome (IBS) in terms of their causes, diagnosis, and treatments.
It is crucial to understand the difference between IBD and IBS to get the correct diagnosis and treatment.
Read on for more information about IBD and IBS, symptoms of IBD vs IBS, and an in-depth IBD and IBS comparison.
What is IBS?
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder, which means that there is a dysfunction in bowel movement, but no structural damage in the digestive tract.
IBS can be very uncomfortable and can impact a person's quality of life. Symptoms may vary from being mildly annoying to severely disabling. This may affect self-confidence, social functioning, work performance, and travel.
Other functional disorders associated with IBS include fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, and temporomandibular joint disorder (TMJ).
Causes of IBS
IBS is believed to be caused by an imbalance between the brain and the gut. Some factors that can trigger IBS include:
- Certain foods
- Emotional stress
- Hormonal fluctuations
- Certain medications
These triggers can lead to spasms in the intestinal tract, which can either slow the passage of stool and cause constipation or accelerate it, causing diarrhoea.
What is IBD?
Inflammatory bowel disease (IBD) is an umbrella term for the chronic gastrointestinal inflammatory conditions, mainly Crohn's disease and ulcerative colitis. IBD is considered a structural disease, while IBS, on the other hand, is a functional disease. Symptoms occur when there is physical damage to the gut, such as inflammation or ulcers, that can be detected through imaging tests, endoscopy, surgery, or biopsy.
While IBD can manifest as a mild illness in some, it can lead to life-threatening complications in others.
Causes of IBD
The exact cause of inflammatory bowel disease (IBD) remains unknown. Researchers think it's caused by a combination of immune system, genetic and environmental factors, which result in chronic inflammation of the digestive tract.
A number of factors can contribute to IBD, including:
- An abnormal immune response that leads the immune system to attack the digestive tract.
- Genetic predisposition and a history of IBD in the family
- Certain environmental influences that affect the gut microbiome
- Limited exposure to germs during early childhood
- Early childhood gastrointestinal infections
- Antibiotic use in the first year of life
These can affect the immune system and gut environment, causing a chronic immune imbalance in the gut.
Differences Between IBS and IBD
Here are some key IBD vs IBS differences:
| Feature | Irritable Bowel Syndrome (IBS) | Inflammatory Bowel Disease (IBD) |
| Faecal Calprotectin Levels | Usually normal or low. Mild elevations may occur in conditions such as post-infectious IBS. A result of <40 µg/g generally suggests no significant inflammation. | Typically elevated due to ongoing intestinal inflammation. Levels >100 µg/g often indicate inflammation consistent with IBD. Values between 40–100 µg/g may require further evaluation. |
| Degree of Inflammation | Generally absent or minimal. If present, inflammation is usually mild and inconsistent. | Chronic inflammation of the intestinal lining is a defining feature and may persist even when symptoms are mild or during remission. |
| Relationship Between Symptoms and Inflammation | Symptoms may occur without any detectable inflammation or structural abnormality. Symptom severity does not correlate with inflammation because inflammation is usually absent. | Inflammation is a hallmark of the disease, but symptom severity does not always match the degree of inflammation seen on endoscopy or other investigations. |
| Inflammatory Markers During Remission | Typically, remain normal. | May remain elevated even when symptoms improve, or the disease is in remission. |
| Diagnostic Significance | Normal calprotectin levels and lack of significant inflammation support an IBS diagnosis. | Elevated calprotectin levels and evidence of chronic intestinal inflammation support an IBD diagnosis. |
Symptoms Shared Between IBS and IBD
Both inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) involve the digestive system and are chronic conditions. Therefore, they also share the following symptoms:
- Abdominal pain
- Bloating
- Diarrhoea or constipation
- Frequent bowel movements
- An urgent need to have a bowel movement
Besides these common symptoms, both conditions are diagnosed in adolescents and young adults, although they may occur at any age.
IBD vs IBS Diagnosis
Regardless of the IBS vs IBD difference, the diagnostic tests for both conditions share some similar elements.
Diagnosing IBD
Doctors check for physical symptoms of damage or inflammation in the digestive tract to diagnose IBD. These may include:
- Blood tests
- Stool tests
- CT scans or MRI scans
- Colonoscopy
A doctor may also take a tissue sample (biopsy) for further examination during a colonoscopy.
When inflammation, ulceration, or damage is seen, it can help to confirm the diagnosis of Crohn's disease or Ulcerative colitis.
Diagnosing IBS
The Rome Criteria are a commonly used diagnostic tool for IBS.
The Rome Criteria are a standardised, symptom-based set of guidelines developed by international experts to diagnose Irritable Bowel Syndrome (IBS). Doctors use these criteria—rather than definitive blood tests or scans—to confidently confirm an IBS diagnosis by identifying specific patterns of pain and bowel habits.
A diagnosis may be considered if a person experiences abdominal pain at least one day per week for three months and the pain is associated with at least two of the following:
- Related to defecation
- Change in stool frequency
- Change in stool form
Sometimes other tests are ordered to exclude other illnesses or to confirm the diagnosis of IBD. The typical findings of bleeding or inflammation usually narrow the diagnostic considerations for IBS, favouring other causes.
Treatment for IBS
Treatment of IBS is aimed at controlling symptoms and improving quality of life, primarily through dietary and lifestyle changes.
- Dietary Modifications: Replacing trigger foods, such as high-FODMAP (Fermentable Oligo-, Di-, Mono-saccharides and Polysaccharides) foods, some dairy products, and gluten-containing foods, can help decrease symptoms. A registered dietitian can be very helpful.
- Stress Management: There's no denying that stress is a known producer of IBS symptoms. Symptoms can be well controlled with mindfulness, meditation, yoga, regular exercise, and cognitive behavioural therapy (CBT).
- Lifestyle Changes: A consistent sleep pattern, drinking plenty of water, and avoiding smoking or alcohol may help to control the symptoms.
- Pharmacological Support: Medications may be prescribed under medical supervision, based on the type of predominant symptom, either diarrhoea or constipation.
Treatment for IBD
The goal of treating an IBD is to decrease inflammation, control symptoms, correct nutritional deficiencies, and prevent complications.
- Immunomodulators: Immunomodulators are medicines that help regulate inflammation by balancing the immune system.
- Biologic Therapies: Biologics are cutting-edge medications that act on specific proteins that play a role in the inflammatory process.
- Dietary Management: While there is no specific food that triggers IBD, making dietary changes during flares can help alleviate symptoms, and an overall healthy eating plan can help promote health.
- Surgical Intervention: Surgery may be needed to remove damaged parts of the intestine or to treat complications.
Reader Information: This article is intended for educational and informational purposes only and should not be considered medical advice, diagnosis, or treatment. The information provided is based on current medical knowledge but may not apply to every individual. If you have persistent digestive symptoms such as abdominal pain, diarrhoea, constipation, rectal bleeding, unexplained weight loss, or changes in bowel habits, consult a qualified healthcare professional for appropriate evaluation and treatment.
FAQs
What is the main difference between IBD and IBS?
The key IBD vs IBS difference is that the inflammation and structural damage are present in IBD, but not in IBS. IBS is more of a functional disorder of the bowel.
What are the common symptoms of irritable bowel disease vs IBS??
Some signs of irritable bowel disease vs IBS include abdominal pain, bloating, diarrhoea, constipation, and stool frequency and consistency. Inflammation, however, can also result in any of the following symptoms of IBD: rectal bleeding, weight loss, fatigue, and malnutrition.
Can IBS develop into IBD?
There is no direct association between IBS and IBD. It is important to note, though, that there are overlapping symptoms and therefore a full medical evaluation is required to differentiate the two conditions.
How is IBD diagnosed?
Blood tests, stool tests, imaging scans, colonoscopy, and biopsy are used to help diagnose the cause of inflammation and ulcers in patients with IBD. There is no single test to confirm the disease; a gastroenterologist will piece together your symptoms, history, and test results to rule out other digestive conditions
How is IBS diagnosed?
The Rome Criteria are the most commonly used method for the diagnosis of IBS. This involves looking at the presence of recurring abdominal pain and bowel habit changes. Further tests are done to exclude the possibility of IBD and other digestive disorders.
Does IBS last for a lifetime?
The condition is usually chronic but can be managed by lifestyle changes, stress reduction, diet changes, and medication as necessary. With the right strategies, you can minimise flare-ups and significantly improve your daily quality of life.
