RCGP SCA Algorithm — UK Primary Care
Appendicitis is the most common surgical emergency in children, with peak incidence at 10–12 years but can occur at any age. Perforation is more common in children than adults because children present later and diagnosis is more challenging due to atypical presentations.
Testicular torsion is time-critical — testicular viability falls with every hour of delay, so refer immediately for same-day surgical/urological assessment and do not wait for ultrasound. Boys with abdominal pain MUST have the scrotum examined. Torsion can present as lower abdominal pain with minimal testicular symptoms.
Non-accidental injury (NAI) should be considered in any child with unexplained abdominal injury, particularly with bruising on the abdominal wall, back, or buttocks. The "seat-belt" bruise pattern across the abdomen in a child not in a road traffic accident is a NAI red flag.
The classic periumbilical → RIF migration of appendicitis pain is often absent in children — atypical presentations are common and include generalised pain, diarrhoea, and vomiting. Appendicitis is primarily a clinical diagnosis. The Paediatric Appendicitis Score (PAS) is an adjunct within a local pathway, not a diagnostic test — scores do not replace serial clinical examination or surgical assessment.
Anorexia is common in appendicitis and is one of the most useful discriminating features — a hungry child with abdominal pain is much less likely to have appendicitis than an anorexic one. Always ask "Has your child been eating normally?" and "Did they want their usual favourite food today?"
Functional abdominal pain (FAP) / centrally mediated abdominal pain syndrome (CAPS) is the most common cause of recurrent abdominal pain in school-age children, but not all recurrent pain is functional. It is not a diagnosis of exclusion after exhaustive negative investigations — after structured assessment, growth review and checking for alarm features, making a positive diagnosis with confidence and communicating it well to families prevents unnecessary tests and builds therapeutic alliance.
HSP (Henoch-Schönlein Purpura / IgA vasculitis) must not be missed — it presents with colicky abdominal pain, arthritis and a purpuric rash on the buttocks and legs. Renal involvement (haematuria, proteinuria) requires urinalysis monitoring over 6 months (UK Kidney Association). Any child with purpuric rash + abdominal pain = HSP until proven otherwise.
The examination of the scrotum in boys with abdominal pain is life-altering if torsion is present. Testicular torsion is missed when the genitalia are not examined. A child with severe abdominal pain presenting at 2am who "just has a tummy ache" may have testicular torsion. Check every time.
Children with peritonism lie very still because movement exacerbates pain. Driving over a speed bump or bumpy car journey increases pain (Dunphy's sign). A child who arrives in the waiting room running around is unlikely to have peritonitis. Observe the child's behaviour before and during the consultation.
Faecal calprotectin is a neutrophil protein released during gut mucosal inflammation — raised in Crohn's and UC. NICE HTG320 (formerly DG11) supports it as an option for children with suspected IBD within a quality-assured local paediatric pathway; it is a targeted test interpreted alongside symptoms, growth and blood results, not a stand-alone rule-in or rule-out or a reassurance test.
Normal blood results (FBC, CRP) do NOT rule out early appendicitis. Use serial examination and clinical judgement rather than a single score, laboratory threshold or ultrasound result. This is a high-stakes clinical decision. If you have a clinical gestalt that "something is wrong," refer even with normal bloods.
Children under 5 with appendicitis have higher perforation rates than older children because: they cannot localise pain well, parents and clinicians attribute pain to constipation or GE, and the omentum is poorly developed so cannot contain perforation. Any child under 5 with significant unexplained abdominal pain should have a low threshold for same-day surgical assessment.
IBD (Crohn's disease) in children can present insidiously over months with abdominal pain, fatigue, and weight loss without obvious bowel symptoms. Perianal disease (fistulae, skin tags) is a recognised feature of Crohn's. Examine the perianal region and refer early — early treatment prevents bowel damage and growth failure.
Next steps: see Constipation (child) · Surgical problems in children · UTI in children · Coeliac disease · Crohn's disease · Hernia · Gastroenteritis
The evidence strongly supports giving analgesia before surgical assessment — three RCTs and a Cochrane review (2011) found analgesia reduces distress without changing surgical outcomes. Withholding analgesia in a child with abdominal pain is poor practice, but signs must still be reassessed after it is given.
For functional abdominal pain, gut-directed hypnotherapy and CBT are more effective than medication in reducing pain episodes and school absenteeism. Medication is usually not required in primary care; antispasmodics (mebeverine, hyoscine) have weak evidence in children. Avoid unnecessary PPI prescribing — gut microbiome effects.
School absenteeism is the most important functional outcome in paediatric chronic abdominal pain. Children who miss school develop educational deficits, social isolation, anxiety, and depression — all of which amplify pain. Supporting normal activity, including school, while recognising the child's individual circumstances is a central part of management.
The gut-brain axis explains functional abdominal pain mechanistically — visceral hypersensitivity, altered gut motility, and central sensitisation all contribute. Explaining this brain-gut connection using age-appropriate language (e.g., "your stomach has its own little brain that gets stressed when you're worried") has been shown to reduce parent catastrophising and improve treatment compliance.
Time-based safety-netting is critical for abdominal pain — "come back if it gets worse" is insufficient. Specify: "If the pain is getting worse, moving to one place, or your child stops eating, becomes feverish or more unwell, go straight to A&E — do not wait for a GP appointment." This specificity correlates with better decision-making by parents and earlier presentation for surgical assessment.
HSP nephritis develops weeks after the initial presentation and is the most serious complication. Frequent urinalysis over 6 months (weekly early, then monthly) with BP checks at diagnosis and when renal involvement is suspected is essential and is often a primary care responsibility. In practice this follow-up urinalysis and BP monitoring is usually led by the GP, so agree who is doing it at discharge.