The textbook picture of coeliac disease — a thin, miserable toddler with chronic diarrhoea — is real, but it's the minority. Most children diagnosed today have a much subtler story: persistent tummy aches dismissed as normal, an unexplained iron deficiency that won't respond to iron drops, slightly off the centile curve, more tired than they should be. By the time someone joins the dots, the child has often had symptoms for two or three years.
The single most important practical point: if you suspect coeliac disease and your child still eats normal bread, pasta, and cereal — keep them eating it until the testing is done. Switching to gluten-free first wipes out the very thing the test is looking for.
Healthbooq covers digestive and nutrition conditions in children, including when something warrants a GP visit and what tests to expect.
What Coeliac Disease Actually Is
Coeliac disease isn't an allergy or an intolerance. It is an autoimmune condition: when someone with coeliac disease eats gluten — the protein in wheat, barley, and rye — the immune system attacks the lining of their own small intestine.
The damage is to the villi, the millions of tiny finger-like projections that line the small bowel and absorb nutrients. Healthy villi look like a deep-pile carpet under a microscope. In active coeliac disease they flatten out, dramatically reducing the absorptive surface. Over time this causes deficiencies — iron, calcium, vitamin D, folate, B12 — and the symptoms that go with them.
About 1 in 100 people in the UK has coeliac disease, and roughly two-thirds of cases are still undiagnosed. The genetic risk is concentrated:
- First-degree relatives of someone with coeliac disease have a 1-in-10 chance of having it themselves.
- Type 1 diabetes — coeliac disease is around five times more common in people with type 1 diabetes.
- Down's syndrome and autoimmune thyroid disease also confer higher risk.
- Coeliac disease can develop at any age — being negative once doesn't mean negative forever, especially for relatives.
Symptoms in Children — Wider Than People Think
The classic presentation:
- Chronic diarrhoea — often pale, frothy, foul-smelling, hard to flush
- Bloated, distended tummy
- Poor weight gain or weight loss
- Misery, especially after meals
This shows up in maybe a third of paediatric cases. The other two-thirds present in less obvious ways:
- Constipation — yes, the opposite of the classic picture. Coeliac disease is found in a small but significant proportion of children investigated for chronic constipation.
- Recurrent abdominal pain without big changes in stool.
- Iron deficiency anaemia that doesn't respond to iron supplements — a classic clue.
- Faltering growth — the child has dropped two centiles on weight or height without obvious cause.
- Fatigue and low energy out of proportion to any explanation.
- Mouth ulcers that keep coming back.
- Dental enamel defects — pitted, discoloured permanent teeth.
- Delayed puberty.
- Behaviour changes — irritability, low mood, brain fog. Often only recognised retrospectively after diagnosis.
- No symptoms at all — picked up via family screening.
If a child has any of these, particularly if they overlap, ask the GP about coeliac testing. It is not a difficult test and there is real harm in delay.
Don't Go Gluten-Free Before Testing
This is the single rule worth repeating loudly:
The child must be eating gluten regularly when the test is done. A normal serving of bread, pasta, or cereal at least once a day for at least six weeks before testing.
Stopping gluten before testing causes the antibodies to fade, the bowel lining to recover, and the test to come back falsely negative. You then either accept a misleading result or have to do a "gluten challenge" — putting the child back on gluten for weeks while they feel ill — to test properly.
If you suspect coeliac and you've already cut gluten, tell the GP. They can plan a structured re-introduction.
How Diagnosis Works
The pathway in the UK has two main steps:
Step 1: Blood test. Your GP can order it.
The main test is IgA anti-tissue transglutaminase antibodies (anti-TTG IgA), raised in active coeliac disease. The lab will also measure total IgA alongside, because around 1 in 400 people has IgA deficiency, in which case the standard test gives a false negative and IgG-based antibodies are needed instead.
Step 2: Specialist referral.
A positive blood test triggers referral to paediatric gastroenterology. NICE guidance (NG20, updated) historically required a small bowel biopsy via endoscopy under light anaesthetic to confirm the diagnosis.
In children specifically, current guidance allows the biopsy to be skipped in some cases — when the antibody level is more than ten times the upper limit of normal, the genetic markers HLA-DQ2/DQ8 are positive, and the child has consistent symptoms. The decision is made by the specialist.
The whole pathway from first GP visit to diagnosis usually takes a few months.
The Gluten-Free Diet
Treatment is the diet. There is no medication, no occasional cheat day, no growing out of it.
What's out:
- Wheat, barley, rye, and anything made from them: most bread, pasta, cous-cous, semolina, cakes, biscuits, breadcrumbs, breaded foods, beer, some sauces and gravies.
- Standard oats — naturally gluten-free, but almost always contaminated by shared milling and farming. Buy specifically labelled gluten-free oats; even then, a minority of coeliacs react to oats themselves.
- Cross-contamination — a shared toaster, fryer, chopping board, or pasta water can be enough to cause damage.
What's safe:
- Rice, potato, corn (maize), buckwheat, quinoa, millet, sorghum.
- All meat, fish, eggs, fruit, vegetables, dairy, pulses in their plain form.
- Certified gluten-free oats.
- Anything labelled "gluten free" — under EU and UK regulation, this means under 20 parts per million.
Hidden gluten turns up in unexpected places: soy sauce, malt vinegar, some sausages, some processed meats, some flavoured crisps, some yoghurts, some medications (excipients), and the wafer used in Christian communion. The Coeliac UK app, available free with annual charity membership, is searchable for thousands of products and is the practical tool most newly diagnosed families use day to day. See coeliac.org.uk.
The "even tiny amounts matter" rule. A child with coeliac disease who eats a single biscuit "just this once" causes measurable bowel damage even if no obvious symptoms follow. Symptoms often disappear on the diet for weeks before any single exposure noticeably reverses them — but the damage accumulates silently and the long-term consequences (osteoporosis, infertility, increased small-bowel cancer risk, persistent anaemia) are real. The diet is non-negotiable, lifelong, and worth taking seriously from the start.
Practical Family Life
A few things help in the early months after diagnosis:
- A dietitian appointment is part of standard NHS follow-up. Take the questions you've collected. Ask about fibre, iron, calcium, B vitamins.
- Set up a separate toaster, butter dish, and cutting board at home. Cross-contamination is the most common reason for ongoing antibodies despite a "gluten-free" diet.
- Brief the school, nursery, and grandparents. Coeliac UK has template letters. Schools have a legal duty under the Equality Act 2010 to provide safe meals.
- Birthday parties and playdates need a script: who provides the food, what the rules are, what the child can eat. The child themselves becomes capable of self-advocacy surprisingly fast — many five-year-olds with coeliac disease can already explain what they can and can't have.
- Eating out has improved significantly in the UK over the past decade; large chains generally have allergen menus, and many smaller places will accommodate. The Coeliac UK Gluten Free Food and Drink Directory lists accredited venues.
- NHS prescription staples — bread, pasta, flour — are still available in some areas but have been cut back. Ask the GP what your local clinical commissioning group provides.
Family Testing
When a child is diagnosed, all first-degree relatives — parents and siblings — should be offered blood testing, even if they have no symptoms. The 1-in-10 risk applies regardless of how well they feel.
Negative once is not negative forever. Coeliac disease can develop later in life. NICE recommends rechecking relatives every few years, particularly if symptoms develop.
Follow-Up
Once on the diet, expected blood-test antibodies fall and most symptoms improve within months. Standard NHS follow-up:
- Annual review with GP or specialist nurse.
- Repeat coeliac antibodies — should be falling and eventually negative on a strict diet.
- Iron, calcium, vitamin D, B12 monitoring.
- Bone density scan in adolescence.
- Growth monitoring through childhood.
If antibodies don't normalise, the most common reason is hidden gluten exposure rather than treatment failure. The dietitian will go through diet diaries and home routines.
Key Takeaways
Coeliac disease affects roughly 1 in 100 UK children — many of them undiagnosed because the symptoms are wider than the textbook picture. Watch for unexplained iron deficiency, faltering growth, persistent tummy aches or constipation as much as classic diarrhoea. The single most important rule before testing: keep the child eating gluten. Going gluten-free first will make diagnosis impossible. Treatment is a strict lifelong gluten-free diet. Siblings and parents have a 1-in-10 chance of also having it and should be tested.
