Dr Peter Gillett is a Consultant Paediatric Gastroenterologist at the Royal Hospital for Sick Children, Edinburgh and has been providing support to the charity for over 10 years. Here, Dr Gillett shares the answers to some commonly asked questions about diagnosis of coeliac disease in children.

Are you born with coeliac disease?

No. To develop the condition, you need the permissibility antigen (HLA-DQ), gluten in the diet and a proposed ‘trigger’. The trigger is often thought to be an infection that allows the mucosal immune system to be exposed to gluten related peptides, which determines if you will develop the condition or not. The majority of individuals with the permissibility antigens do not develop the condition, given that 40% or so of the UK population carry these antigens but only around 1% of the population will develop coeliac disease.

If coeliac disease is suspected, should an outpatients referral be made?

If coeliac disease is suspected, a referral for the blood test is the entry point into diagnosis. It is often not necessary to make an outpatients referral at this point and is likely to be quicker than waiting for an outpatient referral.

What is the youngest age that a child can be tested for coeliac disease?

Infants can be tested for coeliac disease around six weeks after gluten is introduced into the diet, if symptoms merit early testing after gluten exposure begins.

In my experience, the youngest infants I have diagnosed with coeliac disease were around 9 months old. The diagnosis of one child was made as they had a sibling who had already been diagnosed with coeliac disease. The parents recognised the symptoms once gluten was introduced to the diet and bloods were strongly positive. Another symptomatic patient had no family history but had classical symptoms.

When would you recommend that children with a family history of coeliac disease are tested?

If a child has symptoms then they should be tested as soon as possible, as long as they are including gluten in their diet.

Children who are asymptomatic but have a family history of coeliac disease would generally be tested during their second year of life. However, if parents are worried about keeping gluten in their diet then there is no harm in testing earlier.

Symptomatic patients may have other causes for their symptoms and this should be taken into account. If their test for coeliac disease is negative, gluten should be kept in the diet and the test repeated. They should also be referred to the local paediatric service for evaluation, due to alternative possibilities (e.g. milk protein allergy/other food intolerance etc). It is important to remember that testing for coeliac disease is not a once in a lifetime test, and of course a test may become positive over time. It is advisable to keep an open mind regarding repeating the test as indicated and not necessarily just going gluten free despite a test being negative. This is where a practical plan may be required with a paediatrician and expert dietitian.

Should a gluten free diet be trialled first before offering a test for coeliac disease?

No, the diagnostic tests currently available for coeliac disease rely on gluten being in the diet. Therefore it is important to not recommend that patients try a gluten free diet before being tested. For children with coeliac disease the gluten free diet can rapidly transform their health and quality of life, however it is a significant undertaking and so certainty with the diagnosis is really important.

In addition, if a gluten free diet provides relief from symptoms then it can be a difficult decision for families to make about whether to reintroduce gluten into the diet to secure a diagnosis. The final diagnosis of coeliac disease should be made in secondary care so referral should be made. The paediatrician or paediatric gastroenterologist will advise when to begin the gluten free diet.

Is genetic testing routinely used for diagnosis of coeliac disease in children?

In 2020 new European diagnosis guidelines were published which removed the need for genetic testing for serological diagnosis of coeliac disease. Genetic testing is therefore no longer routinely used in the diagnosis pathway.

Genetic testing may be used where the diagnosis is uncertain but is only recommended for use in specialist settings, usually under the auspices of the local coeliac service. Having the genes associated with coeliac disease is necessary but not sufficient to develop coeliac disease.

A negative genetic test can therefore be helpful in ruling out coeliac disease but a positive genetic test does not mean that the individual will definitely develop coeliac disease.

Coeliac Disease: The Facts

• Coeliac disease is a common autoimmune disease affecting 1 in 100 people in the UK
• Only 36% of people with coeliac disease are currently diagnosed in the UK
• Gluten must remain in the diet before and during testing for coeliac disease
• Coeliac UK is an independent charity, that was founded over 50 years ago and advocates for people with coeliac disease and gluten related conditions
• NICE recommends total immunoglobulin A (IgA) and tissue transglutaminase IgA as the first choice test in diagnosis
• For children, a biopsy may not be required in all cases for diagnosis of coeliac disease. This decision should be made by a paediatric gastroenterology or paediatrician with an interest in gastroenterology

Read the NICE guidelines