Irritable Bowel Syndrome
Irritable bowel syndrome (IBS) is a common disorder of gut–brain interaction that can cause abdominal pain, bloating and changes in bowel habit, including diarrhoea, constipation or both. A careful assessment helps confirm the diagnosis, identify warning features and tailor treatment to your predominant symptoms and triggers.
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Understanding Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a disorder of gut–brain interaction characterised by recurrent abdominal pain associated with bowel movements and changes in stool frequency or form. The bowel usually appears structurally normal, but its movement and sensitivity can be altered.
Symptoms can be influenced by several factors, including gut sensitivity, bowel motility, diet, stress, sleep and, in some people, a previous episode of gastroenteritis. IBS does not cause bowel inflammation and does not itself increase colorectal cancer risk.
Common Symptoms
IBS Subtypes
IBS-D (Diarrhoea-predominant)
Characterised by frequent loose stools and urgency. Symptoms may be more noticeable at particular times of day, including the morning.
IBS-C (Constipation-predominant)
Infrequent, hard stools with straining. Often associated with bloating and abdominal discomfort.
IBS-M (Mixed)
Alternating between diarrhoea and constipation. Symptoms may vary day to day or week to week.
IBS-U (Unclassified)
Meets IBS criteria but stool patterns don't fit clearly into other subtypes.
Common Triggers
Identifying and managing triggers is key to controlling IBS symptoms. Triggers vary between individuals.
Dietary
- FODMAPs (fermentable carbohydrates)
- Fatty or fried foods
- Caffeine and alcohol
- Artificial sweeteners
- Large meals
Lifestyle
- Psychological stress
- Anxiety and depression
- Poor sleep
- Lack of exercise
- Irregular eating patterns
Other
- Hormonal changes (menstruation)
- Recent gastrointestinal infection
- Antibiotic use
- Food intolerances
- A previous episode of gastroenteritis
When Should You See a Doctor?
IBS itself does not usually cause bleeding, unexplained weight loss, anaemia, fever or steadily progressive symptoms. These features should prompt medical assessment.
Rectal Bleeding
Blood in the stool is not explained by IBS and should be medically assessed.
Unexplained Weight Loss or Anaemia
Unintentional weight loss or unexplained anaemia may indicate another condition and needs further evaluation.
Night-Time or Progressive Symptoms
Symptoms that regularly wake you from sleep, become progressively worse, or are accompanied by fever warrant review.
New or Changing Symptoms
New symptoms later in life, a significant change in bowel habit, or a relevant family history may require further investigation.
Diagnosis
IBS is diagnosed based on symptom criteria (Rome IV) after excluding other conditions. Testing may be needed to rule out alternative diagnoses.
When Colonoscopy is Needed
Colonoscopy may be recommended to exclude inflammatory bowel disease, microscopic colitis, or colorectal cancer.
- Presence of alarm symptoms
- Age over 50 without prior screening
- Family history of colorectal cancer or IBD
- Symptoms not responding to treatment
Other Tests
Blood Tests
Full blood count, inflammatory markers, coeliac serology, thyroid function.
Stool Tests
Calprotectin (to exclude IBD), stool cultures, ova and parasites.
Breath Tests
Hydrogen breath tests for lactose intolerance or SIBO (small intestinal bacterial overgrowth).
Food Intolerance Testing
Structured elimination diets may identify specific triggers.
Many digestive symptoms such as abdominal discomfort, bloating, diarrhoea, constipation, and changes in bowel habits are commonly attributed to Irritable Bowel Syndrome. However, some of these symptoms can also occur in Inflammatory Bowel Disease, a group of conditions that cause ongoing inflammation within the digestive tract.
Although IBS and IBD may share certain symptoms, they are fundamentally different conditions. IBS is considered a functional bowel disorder, meaning the bowel appears normal but does not function normally. In contrast, IBD involves actual inflammation and damage to the lining of the digestive tract and may lead to more serious complications if left untreated.
Understanding the differences between IBS and IBD is important, as the investigations, treatment approaches, and long-term implications can vary significantly.
IBS
Irritable Bowel Syndrome
What is it?
A functional bowel disorder affecting how the digestive system works
Examples
IBS with diarrhoea, constipation, or mixed bowel habits
Common symptoms
Bloating, abdominal pain, diarrhoea, constipation, excess gas
Blood in stool
Uncommon
Weight loss
Usually absent
Fever
No
Inflammation in the bowel
No visible inflammation
Damage to the intestine
No
Symptoms during sleep
Uncommon
Cause
Related to gut sensitivity, bowel movement changes, stress, and diet
Is it serious?
Not dangerous, but can affect quality of life
Tests commonly performed
Usually diagnosed based on symptoms and simple tests
Treatment
Diet, lifestyle changes, stress management, symptom control
Cancer risk
Does not increase bowel cancer risk
When to seek specialist review
Persistent or troublesome symptoms
IBD
Inflammatory Bowel Disease
What is it?
A chronic inflammatory condition of the digestive tract
Examples
Crohn's disease and ulcerative colitis
Common symptoms
Abdominal pain, diarrhoea, urgency, rectal bleeding, weight loss
Blood in stool
Common
Weight loss
More common
Fever
Can occur during active inflammation
Inflammation in the bowel
Yes
Damage to the intestine
Can occur over time
Symptoms during sleep
May occur
Cause
Immune-related inflammation of the digestive tract
Is it serious?
Can lead to complications if untreated
Tests commonly performed
May require blood tests, stool tests, colonoscopy, and imaging
Treatment
Anti-inflammatory medication, immune therapy, and sometimes surgery
Cancer risk
Long-standing disease may increase bowel cancer risk
When to seek specialist review
Any ongoing diarrhoea, bleeding, weight loss, or worsening symptoms
IBS Treatment Approach
Effective IBS management in Singapore is highly individualized, integrating dietary changes, lifestyle modifications, and targeted medications tailored to predominant symptoms, under the guidance of an experienced IBS specialist doctor.
Dietary Management
- Low FODMAP diet (guided by dietitian)
- Identify and avoid personal triggers
- Regular meal patterns
- Adequate fibre intake (adjusted to tolerance)
- Limit caffeine and alcohol
- Probiotics (strain-specific)
Medications
For Pain/Spasm
Antispasmodics (mebeverine, hyoscine), peppermint oil capsules.
For IBS-D
Loperamide, bile acid binders, rifaximin (for bloating/SIBO).
For IBS-C
Osmotic laxatives, linaclotide, prucalopride.
Neuromodulators
Low-dose tricyclic antidepressants or SSRIs for pain modulation and gut-brain axis.
Psychological Therapies
CBT, gut-directed hypnotherapy, mindfulness - evidence-based for IBS.
Management of Your IBS
IBS management works best when treatment is tailored to your predominant symptoms, bowel pattern and individual triggers. The aim is to reduce flare-ups, improve day-to-day comfort and help you maintain a more predictable routine.
Managing IBS Flare-Ups
Flare-ups can cause abdominal pain, bloating, diarrhoea, constipation, urgency or a feeling of incomplete evacuation. Symptoms often vary over time, so management may need to change depending on whether diarrhoea, constipation, pain or bloating is most troublesome.
Common Triggers for IBS Flare-Ups
How IBS Is Managed
Diet and eating pattern
Regular meals, adequate hydration and identifying personal food triggers can be helpful. A low-FODMAP diet may be useful in selected patients, ideally with dietetic guidance.
Bowel-pattern treatment
Treatment can be directed at the predominant bowel pattern, for example constipation, diarrhoea or mixed symptoms.
Pain and bloating
Antispasmodics, peppermint oil or other symptom-directed treatments may help selected patients.
Gut–brain therapies
Stress management, cognitive behavioural therapy and gut-directed hypnotherapy can be useful when symptoms are strongly influenced by the gut–brain interaction.
Lifestyle
Regular exercise, adequate sleep and a consistent daily routine can help reduce symptom variability.
When to Seek Further Medical Review
Seek medical assessment if any of the following warning signs are present:
A gastroenterologist can help confirm the diagnosis, exclude other digestive conditions and tailor treatment to your individual symptom pattern.
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