Inflammatory bowel disease in children is underdiagnosed. The symptoms – abdominal pain, changes in bowel habit, fatigue, and poor weight gain – overlap with many common childhood conditions, and it can take months to years from first symptoms to diagnosis. Delayed diagnosis in children carries an additional cost: during the window of untreated inflammation, growth can be impaired and puberty delayed, and the opportunity to protect long-term height and development is missed.
Crohn's disease is one of the two main forms of IBD (the other being ulcerative colitis). It is distinguished by its ability to affect any part of the gut from mouth to anus, by transmural (full-thickness) inflammation, and by the characteristic granulomatous pathology seen on biopsy. In children it tends to be more extensive than in adults, and the approach to treatment is meaningfully different at younger ages.
Healthbooq (healthbooq.com) covers gastrointestinal health in children.
What Crohn's Disease Is
Crohn's disease is a chronic relapsing and remitting inflammatory condition of the gut. The inflammation is not continuous (unlike ulcerative colitis, which affects a continuous section of colon) but patchy, and it involves all layers of the gut wall. The most commonly affected sites in children are the terminal ileum and ileocaecal region (around the join between the small and large intestine), though disease can involve the upper gut, perianal region, or colon.
The cause is not fully understood. Crohn's disease results from a dysregulated immune response to gut bacteria in a genetically susceptible host, triggered by environmental factors. The rise in paediatric IBD incidence over recent decades – a 2021 analysis found a 50% increase in paediatric Crohn's in the UK over the preceding decade – points strongly to environmental and microbiome-related factors alongside genetic predisposition.
Symptoms in Children
The classic triad of abdominal pain, diarrhoea, and weight loss is well-recognised, but presentation in children is often more subtle and protracted.
Abdominal pain, typically in the right lower abdomen (ileocaecal region) or central, is very common. Rectal bleeding is less common in Crohn's than in ulcerative colitis. Loose or frequent stools may not be as dramatic as in colitis. Fatigue, reduced appetite, and low-grade fever are common.
Growth impairment – falling centiles on height or weight charts – is a key paediatric indicator and may precede any gut symptoms. Linear growth impairment is caused by chronic inflammation, nutritional deficiency (particularly zinc and iron), and elevated inflammatory cytokines that suppress growth hormone axis function. A child who is well below expected height for their family, or whose growth has slowed significantly without explanation, warrants investigation.
Delayed puberty is a related concern: untreated Crohn's disease in adolescence can significantly delay pubertal development.
Perianal disease – skin tags, fissures, fistulae, or abscesses around the anus – is common in paediatric Crohn's and may precede intestinal symptoms by months.
Investigation
Blood tests showing raised inflammatory markers (CRP, ESR), low albumin, anaemia (particularly iron deficiency anaemia), and low platelets or raised platelet count are typical but not specific. Faecal calprotectin is a marker of gut inflammation released by white blood cells in the gut lumen. Elevated faecal calprotectin (above 250 micrograms per gram) in a symptomatic child strongly supports IBD and is used as a first-line triage test in NICE guidance (NG129).
Definitive diagnosis requires endoscopy (ileocolonoscopy with biopsies) and typically MRI or CT enterography to assess the small bowel.
Treatment: The Role of Exclusive Enteral Nutrition
The most distinctive aspect of paediatric Crohn's disease management is that exclusive enteral nutrition (EEN) – where the child's entire dietary intake is replaced by a formula drink or tube feed for 6-8 weeks – is the preferred first-line treatment for inducing remission in children. Multiple systematic reviews and NICE guidance confirm EEN is as effective as corticosteroids for inducing mucosal healing, with the additional benefits of improving nutritional status, supporting linear growth, and avoiding the bone density and growth-suppressing effects of steroids.
EEN is challenging: the child eats and drinks nothing but formula for 6-8 weeks. Compliance is the main barrier. Nasogastric tube feeding overnight is sometimes used alongside daytime formula drinks to support intake.
After EEN, maintenance treatment typically uses immunomodulators (azathioprine or mercaptopurine) or biological therapies (anti-TNF agents such as adalimumab or infliximab). Adalimumab and infliximab are licensed for use in paediatric Crohn's disease and have transformed outcomes.
Impact on School and Daily Life
Children and young people with Crohn's disease need support at school. Access to toilet facilities promptly, flexibility during flares, a healthcare plan, and communication between the gastroenterology team and school are all important. Crohn's & Colitis UK (crohnsandcolitis.org.uk) has resources specifically for young people and schools.
Key Takeaways
Crohn's disease is a chronic inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract from mouth to anus. Paediatric Crohn's disease (onset before 17 years) accounts for approximately 25% of all Crohn's cases in the UK and often presents with a more extensive disease distribution than adult-onset disease. Key symptoms include abdominal pain, diarrhoea (often without blood in Crohn's, unlike ulcerative colitis), weight loss, and faltering growth. Growth impairment and delayed puberty are important specific concerns in children. First-line treatment for inducing remission in children is exclusive enteral nutrition (EEN) – a liquid formula diet replacing all food intake for 6-8 weeks – which is as effective as steroids and avoids steroid side effects on growth and bone. Maintenance treatment uses immunomodulators and biological therapies.
