Quick answer. Crohn’s disease is a long-term inflammatory bowel disease that can affect any part of the digestive tract, causing abdominal pain, diarrhoea (sometimes bloody), weight loss and fatigue. It is managed with medicines that control inflammation, and severe pain, heavy bleeding or high fever needs urgent care.
Crohn’s disease is a type of inflammatory bowel disease (IBD) in which the lining of the digestive tract becomes inflamed. Unlike ulcerative colitis, which is limited to the colon, Crohn’s disease can affect any part of the gut from the mouth to the anus, most commonly the end of the small intestine and the start of the colon. It is a lifelong condition that tends to flare and settle over time.
This guide explains what Crohn’s disease is, its symptoms, how it differs from irritable bowel syndrome (IBS) and ulcerative colitis, how a gastroenterologist diagnoses it, and the treatments available in Singapore. It also covers the warning signs that mean you should seek care urgently.
At a glance
| Feature | Crohn's disease | Ulcerative colitis / IBS |
|---|---|---|
| Where | Any part of the gut | UC: colon only; IBS: no inflammation |
| Inflammation | Yes, can be patchy & deep | UC: continuous in colon; IBS: none |
| Bleeding | Sometimes | UC: often; IBS: no |
| Weight loss | Common | UC: possible; IBS: uncommon |
| Diagnosis | Scope, scans, biopsy | UC: colonoscopy; IBS: clinical |
What is Crohn's disease?
Crohn’s disease is a chronic (long-term) inflammatory bowel disease. The immune system mistakenly attacks the lining of the digestive tract, causing inflammation that can run deep into the bowel wall and appear in patches with healthy areas in between. It can affect any part of the gut but most often involves the lower small intestine and the colon.
It often starts in younger adults but can begin at any age. Crohn’s disease typically follows a pattern of flare-ups, when symptoms are active, and remission, when they are quiet. While it cannot currently be cured, modern treatments can control inflammation well and help many people lead full lives.
Symptoms & signs
Symptoms vary depending on which part of the gut is affected and how active the disease is. Common features include:
- Recurring abdominal pain and cramping
- Persistent diarrhoea, sometimes with blood or mucus
- Unintended weight loss
- Fatigue and feeling generally unwell
- Reduced appetite
- Mouth ulcers
- Sometimes problems around the anus, such as soreness or fistulas
Some people also have symptoms outside the gut, such as joint pains, eye inflammation or skin rashes. In children, Crohn’s can slow growth.
Causes & risk factors
The exact cause is not fully understood, but Crohn’s is thought to result from a combination of an overactive immune response, genetic susceptibility and environmental factors. Things linked to a higher risk include:
- A family history of inflammatory bowel disease
- Smoking, which raises the risk and can worsen Crohn’s
- Age – it often starts in adolescence or early adulthood
- Possibly some aspects of diet and gut bacteria, though these are still being studied
Crohn’s disease is not caused by anything you did wrong, and it is not contagious.
How it's diagnosed
Because the symptoms overlap with IBS, ulcerative colitis and infections, a doctor uses several tests to confirm Crohn’s disease and map where it is active:
- Blood tests – for inflammation, anaemia and nutrition
- Stool tests – including a marker of bowel inflammation and tests to rule out infection
- Colonoscopy with biopsies – to look at the bowel lining and take tissue samples
- Scans – such as MRI or CT to assess the small bowel and check for complications
This combination helps distinguish Crohn’s from ulcerative colitis (which affects only the colon and continuously) and from IBS (which causes symptoms without inflammation or bleeding).
Treatment options
The aim of treatment is to calm inflammation, control symptoms, achieve and maintain remission, and prevent complications. Options include:
- Anti-inflammatory medicines – including steroids to settle a flare
- Immune-modifying medicines – to keep the disease under control longer term
- Biologic therapies – targeted medicines for moderate to severe disease
- Nutritional support – to address weight loss and deficiencies
- Surgery – to remove a badly affected segment or treat complications such as a blockage, fistula or abscess
Treatment is tailored to the individual and adjusted over time. Stopping smoking is one of the most helpful things a person with Crohn’s can do.
When to see a doctor & which specialist
See a doctor if you have persistent diarrhoea, recurring abdominal pain, blood in your stool, unexplained weight loss or ongoing fatigue, so the cause can be investigated. Seek urgent care or call 995 if you have severe abdominal pain, heavy or persistent rectal bleeding, a high fever with a very swollen tender abdomen, or signs of severe dehydration – these can indicate a serious flare or complication.
Crohn’s disease is diagnosed and managed by a gastroenterologist, often with a wider team. You can find one through our directory of best gastroenterologists in Singapore.
Self-management at home
Alongside your medicines, some everyday steps can help you stay well between flares. Eating regular, balanced meals supports nutrition, and a simple food-and-symptom diary can reveal foods that consistently trigger discomfort; during a flare, lighter and lower-fibre meals are sometimes easier to tolerate. Stopping smoking is one of the most effective things you can do, as smoking worsens Crohn’s. Keep your appointments, take medicines as prescribed even when you feel well, and stay up to date with vaccinations, since some treatments affect the immune system. Iron, vitamin B12 or vitamin D levels are sometimes checked, as inflammation and reduced absorption can lead to deficiencies.
Questions to ask your doctor
- Which parts of my gut are affected, and how active is the disease?
- What is the plan if I have a flare, and when should I seek urgent help?
- Could treatment affect fertility, pregnancy or my children?
- Do I need supplements or monitoring for my nutrition?
Common questions
Can I have a normal life with Crohn’s?
Many people do. Modern treatments often control inflammation well, allowing study, work, travel and family life with planning and regular follow-up.
Does MediSave help with the cost?
MediSave can be applied to eligible hospital stays and day-surgery procedures within set limits, and MediShield Life helps cover large hospital bills for Singapore Citizens and Permanent Residents. Ask the clinic’s billing team about your situation.
Related guides
- Best Gastroenterology Clinics in Singapore — our editorial shortlist
- gastroenterology clinics directory
- Diverticulitis
- Pancreatitis
- Ulcerative colitis
- Coeliac disease
- Keratosis pilaris
Sources
- NHS – Crohn's disease
- Mayo Clinic – Crohn's disease
- HealthHub Singapore
- SingHealth – Conditions & Treatments
Part of our Digestive, liver & gut guides · Browse all health topics