Quick answer. Coeliac disease is an immune reaction to gluten that damages the lining of the small intestine, causing diarrhoea, bloating, fatigue, weight loss and anaemia. The only treatment is a lifelong gluten-free diet – but do not start cutting out gluten before testing, as this can hide the diagnosis.
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Coeliac disease is a condition in which eating gluten – a protein found in wheat, barley and rye – triggers the immune system to attack and damage the lining of the small intestine. This damage stops the gut absorbing nutrients properly, which can lead to a wide range of symptoms and, over time, deficiencies such as anaemia. It is a lifelong autoimmune condition, not a simple food intolerance.
This guide explains what coeliac disease is, the symptoms it can cause, how it is diagnosed, and why the only effective treatment is a strict, lifelong gluten-free diet. One crucial point runs throughout: do not start a gluten-free diet before you have been tested, because doing so can make the condition very difficult to diagnose.
At a glance
| Feature | Coeliac disease | Sensitivity / wheat allergy |
|---|---|---|
| Mechanism | Autoimmune, damages gut | Sensitivity: unclear; allergy: immune |
| Gut damage | Yes | No (sensitivity); no (allergy) |
| Diagnosis | Blood test + biopsy | By exclusion / allergy testing |
| Treatment | Lifelong gluten-free diet | Avoid triggers as advised |
| Test first? | Yes – before going gluten-free | Discuss with a doctor |
What is coeliac disease?
Coeliac disease is an autoimmune condition in which the immune system reacts to gluten and damages the tiny finger-like projections (villi) that line the small intestine. These villi help absorb nutrients from food, so when they are flattened by inflammation, the body struggles to absorb what it needs.
It can develop at any age, in childhood or adulthood, and is more likely in people who have a close relative with the condition or who have certain other autoimmune conditions, such as type 1 diabetes or autoimmune thyroid disease. It is a lifelong condition, but with the right diet the gut lining can heal and symptoms can resolve.
Symptoms & signs
Symptoms vary widely from person to person, and some people have very few gut symptoms at all. Possible features include:
- Diarrhoea, sometimes with pale, foul-smelling stools
- Bloating, wind and abdominal pain
- Tiredness and fatigue
- Unintended weight loss
- Iron-deficiency anaemia or other nutrient deficiencies
- Mouth ulcers
- In children, poor growth or delayed development
Some people develop an itchy, blistering skin rash (dermatitis herpetiformis) linked to coeliac disease. Because symptoms are so variable, the condition is often missed for a long time.
Causes & risk factors
Coeliac disease is caused by an abnormal immune response to gluten in people who are genetically predisposed. It is not caused by anything you did, and it is not an allergy or an infection. Factors that raise the likelihood include:
- A family history of coeliac disease
- Certain genetic markers (most people with coeliac carry them, though many people who carry them never develop the disease)
- Other autoimmune conditions, such as type 1 diabetes or autoimmune thyroid disease
- Some genetic conditions, such as Down’s syndrome and Turner syndrome
Gluten is the trigger, but it is not the underlying cause – the condition reflects how a susceptible immune system responds to it.
How it's diagnosed
It is very important to keep eating gluten while being tested. Do not start a gluten-free diet before testing – removing gluten allows the gut to heal, which can give falsely normal results and make coeliac disease very hard to confirm. Diagnosis usually involves:
- Blood tests – looking for specific antibodies (such as tTG) that suggest coeliac disease
- Endoscopy with biopsy – samples taken from the small intestine to look for the characteristic damage, which is the key confirmatory test
- Further blood tests – to check for anaemia and nutrient deficiencies
If you have already gone gluten-free, tell your doctor, as you may need to reintroduce gluten under guidance before testing.
Treatment options
The only effective treatment is a strict, lifelong gluten-free diet. This means avoiding all foods containing wheat, barley and rye, and being careful about hidden sources and cross-contamination. With a gluten-free diet:
- Symptoms usually improve, often within weeks
- The gut lining can heal over months
- The risk of long-term complications is reduced
A dietitian can help you follow a balanced gluten-free diet and avoid deficiencies. Your doctor may also treat any anaemia or vitamin and mineral deficiencies, and arrange follow-up to confirm you are responding. Even small amounts of gluten can cause harm, so the diet needs to be lifelong and consistent.
When to see a doctor & which specialist
See a doctor if you have ongoing diarrhoea, bloating, fatigue, unexplained weight loss or anaemia, or if a close relative has coeliac disease and you have symptoms. Remember to keep eating gluten until you have been tested. While coeliac disease is not usually an emergency, seek urgent care or call 995 if you ever have severe abdominal pain, persistent vomiting or signs of serious dehydration.
Coeliac disease is diagnosed and managed by a gastroenterologist, often with a dietitian. You can find one through our directory of best gastroenterologists in Singapore.
Get tested before going gluten-free
The single most important practical step is to keep eating gluten until testing is complete. Removing gluten early lets the gut heal, which can make blood tests and biopsy results appear normal even when coeliac disease is present. If you have already cut out gluten, tell your doctor, as you may need to reintroduce it under guidance before testing.
Living gluten-free day to day
A strict, lifelong gluten-free diet is the only effective treatment. With practice it becomes more manageable:
- Learn to read food labels and watch for hidden gluten in sauces, soups, processed foods and some seasonings.
- Be mindful of cross-contamination at home and when eating out, such as shared toasters, utensils or frying oil.
- When dining out, including at hawker centres, ask how dishes are prepared, as soy sauce and wheat-based ingredients are common.
- Work with a dietitian to keep your diet balanced and to avoid nutrient deficiencies.
What to expect at the appointment
The doctor will ask about your symptoms, family history and any related conditions, then arrange blood tests for coeliac antibodies. An endoscopy with a small intestine biopsy is usually needed to confirm the diagnosis. Follow-up checks help confirm that the gut is healing and that any anaemia or deficiencies are corrected.
Common questions
Is coeliac disease the same as a wheat allergy or gluten sensitivity?
No. Coeliac disease is an autoimmune condition that damages the gut lining, diagnosed with blood tests and a biopsy. A wheat allergy and gluten sensitivity are different and are assessed in other ways.
Can even a little gluten cause harm?
Yes. Even small amounts can trigger damage, so the diet needs to be strict and lifelong, with care taken over hidden sources and cross-contamination.
Related guides
- Best Gastroenterology Clinics in Singapore — our editorial shortlist
- gastroenterology clinics directory
- Diverticulitis
- Pancreatitis
- Crohn's disease
- Ulcerative colitis
- Keratosis pilaris
Sources
- NHS – Coeliac disease
- Mayo Clinic – Celiac disease
- HealthHub Singapore
- SingHealth – Conditions & Treatments
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