Coeliac Disease (Paediatric)

(For the full adult-oriented workup, see coeliac disease in gastroenterology — this page covers the paediatric-specific serology pathway.) Coeliac disease is an immune-mediated condition in which gluten exposure damages the small bowel mucosa in genetically susceptible people. Gluten is found in wheat, barley, oats and rye. Tissue transglutaminase (tTG) is present throughout the body with roles including wound healing; anti-tTG antibodies are produced on gluten exposure in people with coeliac disease. Roughly 1 in 70 Australians have coeliac disease, but only around 20% are ever diagnosed — up to half of people with the condition have no symptoms at all, so a low threshold to test is needed rather than waiting for classical malabsorption to appear.

Symptoms

Intermittent diarrhoea, abdominal pain, flatulence, bloating — also consider in unexplained poor growth or iron-deficiency anaemia. Children with coeliac disease often present with more classical gastrointestinal complaints than adults do, but extra-intestinal and behavioural features are common and easy to miss — anxiety, depression, aggressive behaviour and sleep problems can all be a presenting feature. The old picture of coeliac disease as a wasting illness is outdated: about a third of people with the disease are overweight or obese at diagnosis, and population studies show weight and symptom pattern alone cannot identify who has it.

Test even asymptomatic children in at-risk groups, since a positive family history carries the strongest predictive value of any single feature: first-degree relatives of someone with coeliac disease have a 10% risk (rising toward 20% if several relatives are affected), and the same low threshold applies to type 1 diabetes, autoimmune thyroid disease, Down syndrome, Turner syndrome, IgA deficiency, and dermatitis herpetiformis. Screening a well, symptom-free child who only has an affected relative can reasonably be delayed until age four.

Diagnosis

• Best first test: tTG-IgA, ideally paired with a total IgA level (or run as a combined tTG-IgA + deamidated gliadin peptide (DGP)-IgG test) — about 3–5% of people with coeliac disease have selective IgA deficiency, which makes IgA-only serology unreliable in them. The tTG assay also has lower sensitivity in children under 3 years old; add DGP-IgG testing alongside tTG-IgA in this age group to avoid a false negative.
• Paediatric no-biopsy pathway: children may be diagnosed without biopsy if tTG-IgA is >10× the upper limit of normal AND a positive EMA (anti-endomysial antibody) is confirmed on a separate sample, per current ESPGHAN 2020 criteria, if the family opts for a non-biopsy approach — a biopsy-avoiding pathway specific to children (not used the same way in adults). HLA-DQ2/DQ8 genotyping is not required for this pathway — an earlier iteration of the same European criteria also required a supportive HLA-DQ2/DQ8 genotype, but ESPGHAN’s 2020 update dropped that requirement. The decision to use a non-biopsy diagnosis should still only be made with specialist paediatric input; the EMA test is labour-intensive and not universally available in Australian labs, so many children will still proceed to gastroscopy in practice even when the serology meets the criteria.
• Genotype (HLA-DQ2/DQ8) testing is mainly useful to exclude coeliac disease, not to confirm it. More than 99% of people with coeliac disease carry HLA-DQ2 or DQ8, so a negative test makes the diagnosis very unlikely; a positive test is far less helpful, since 30–50% of the general population also carry these genes and only about 10% of those who test positive actually have coeliac disease.
• Serology positive, or the no-biopsy pathway isn’t met: refer for gastroscopy with duodenal biopsy — still the gold-standard confirmatory test. Testing must be done on a gluten-containing diet; a child already on a gluten-free diet needs a supervised gluten challenge before retesting, as neither serology nor histology is reliable once gluten has been withdrawn.
• Mild-to-moderately raised tTG is non-specific and can occur in other conditions — IBD, oesophagitis, rheumatoid arthritis, and others.
• Family screening: first-degree relatives should be tested; combining HLA-DQ2/DQ8 genotyping with serology is more informative in relatives than serology alone, and a relative who lacks both susceptibility genes needs no further monitoring.

After diagnosis

Screen and treat nutrient deficiencies (iron, B12, vitamin D, calcium, folate), check bone mineral density, and review immunisation status — pneumococcal vaccination is worth particular attention, since functional hyposplenism raises pneumococcal infection risk in coeliac disease. Coeliac antibody titres are expected to start falling within 3–6 months of starting a gluten-free diet, though they can stay mildly elevated despite good adherence; persistently high titres or ongoing symptoms should prompt referral to a dietitian to check for dietary gluten exposure rather than an assumption of treatment failure. Repeat bone mineral density testing every two years is reasonable. Unlike in adults, resolving tTG titres in children correlate reasonably well with mucosal healing, so a child who improves clinically and normalises serology on a gluten-free diet does not routinely need a follow-up endoscopy to confirm healing.

Practical note: gluten labelling

Food labels must declare wheat, barley, oats and rye where present as an ingredient. Glucose syrup from wheat, dextrose from wheat, and caramel colour from wheat are all gluten-free (highly processed to remove the protein) and do not need to be avoided. Oats themselves remain a grey area: some people with coeliac disease react to the avenin protein in oats, and oats are often processed alongside wheat with a real cross-contamination risk, so current advice is still to avoid oats on a gluten-free diet unless a dedicated gluten-free oat product is used.