Coeliac disease

What is coeliac disease?

Coeliac disease is an autoimmune condition where eating gluten, a protein found in wheat, barley and rye, causes your immune system to attack the lining of your own gut. This damages your small intestine and stops your body from absorbing nutrients properly from food.

Symptoms of coeliac disease

Coeliac disease can cause a wide range of symptoms, and severity varies a lot between people. Some have no noticeable symptoms at all. Gut symptoms can include:

• diarrhoea, which may smell particularly unpleasant
• stomach aches, bloating and wind
• indigestion
• constipation.

You might also notice more general symptoms, such as:

• extreme tiredness (fatigue), often linked to not getting enough nutrients from food
• unexplained or unintentional weight loss
• an itchy rash with blisters, called dermatitis herpetiformis, often on the elbows, knees or buttocks
• mood changes, such as irritability, low mood or anxiety
• missed or irregular periods, or difficulty getting pregnant
• nerve problems, such as tingling or numbness, or difficulties with coordination and balance.

Children with coeliac disease may not grow at the expected rate and can have delayed puberty.

Causes and who is at risk

Coeliac disease is an autoimmune condition, brought on by eating gluten in people who are genetically predisposed to it. It's not entirely clear why the immune system reacts this way, but a combination of genetics and environmental factors seems to be involved.

Almost everyone with coeliac disease carries a particular gene variant, called HLA-DQ2 or HLA-DQ8, inherited from a parent. However, most people with these genes never develop the condition, so something else must trigger it too.

You're at higher risk if you:

• have a first-degree relative (parent, sibling or child) with coeliac disease – this raises your own risk to around 1 in 10
• have another autoimmune condition, such as type 1 diabetes or autoimmune thyroid disease
• have a chromosomal condition such as Down syndrome, Turner syndrome or Williams syndrome
• are female – coeliac disease is diagnosed more often in women than men.

It's thought to affect at least 1 in 100 people, both in the UK and worldwide, though many cases go undiagnosed or are mistaken for other conditions, such as irritable bowel syndrome (IBS).

Are there different types of coeliac disease?

Coeliac disease itself isn't usually split into separate named types, but it can look different from person to person:

• Some people have clear gut symptoms
• Some have mainly non-gut symptoms, such as tiredness, joint or nerve problems, or a skin rash
• Some have no noticeable symptoms at all, sometimes called 'silent' coeliac disease, and are only diagnosed after tests for another condition, or because a close relative has been diagnosed.

Some people with coeliac disease also develop a separate, related skin condition called dermatitis herpetiformis, an itchy rash with blisters that's triggered by gluten in the same way.

How is coeliac disease diagnosed?

There's no single test for coeliac disease, so your doctor will usually use a combination of:

• a blood test, checking for specific antibodies your body produces in response to gluten
• a biopsy of your small intestine, taken during an endoscopy (a thin tube with a camera passed down into your gut), to look for damage to its lining – this is considered the most reliable way to confirm the diagnosis.

You may also have blood tests to check for nutrient deficiencies, such as iron or vitamin D, since these are common if your gut has been struggling to absorb nutrients.

It's important to keep eating gluten in the run-up to testing, and not start a gluten-free diet until your diagnosis is confirmed, even if an early blood test is positive. Cutting out gluten beforehand can affect the accuracy of the results. On average, it can take around four years from symptoms starting to getting a diagnosis, and sometimes longer.

How is coeliac disease treated?

There's no cure for coeliac disease, but the good news is that treatment is very effective. The only treatment is a strict, lifelong gluten-free diet, cutting out all foods containing wheat, barley and rye, including obvious sources like bread, pasta and beer, and less obvious ones like sauces and ready meals.

Even small amounts of gluten, for example from crumbs on a cutting board or in a toaster, can trigger damage to your gut again, so it needs to be strict.

Most people notice their symptoms improve within weeks of going gluten-free, though it can take several months, or occasionally longer, for your gut lining to fully heal, and eating any gluten during this time can delay your recovery.

Alongside diet, your doctor or dietitian may also recommend:

• vitamin or mineral supplements, for example for iron deficiency, while your gut heals and starts absorbing nutrients properly again
• medicine such as dapsone, if you have dermatitis herpetiformis and the rash takes longer to clear than your other symptoms
• steroid or immune-suppressing medicine, in rare cases where symptoms persist despite a strict gluten-free diet (sometimes called refractory coeliac disease), after other possible causes have been ruled out.

You'll usually have an annual review with your GP, who'll check your height and weight, review your symptoms and diet, and assess whether you need any further support, such as specialist dietary advice.

When should I see a doctor?

See your doctor if you have ongoing gut symptoms such as diarrhoea, bloating or stomach pain, or unexplained tiredness, weight loss or an itchy rash – especially if these don't settle or keep coming back.

It's also worth being tested if you have a first-degree relative (parent, sibling or child) with coeliac disease, or another condition linked to a higher risk – such as type 1 diabetes or an autoimmune thyroid condition – even if you don't have obvious symptoms yourself.

The longer coeliac disease goes undiagnosed and untreated, the greater the risk of long-term complications, so it's worth getting persistent symptoms checked rather than living with them. Importantly, don't stop eating gluten before you're tested, as this can affect the accuracy of the results.