Abdominal Pain in Children: Appendicitis and Functional Pain

"My tummy hurts" is the least specific complaint in paediatrics: behind it sits everything from hunger and school anxiety to a condition needing surgery within hours. The good news is that the distinction rests on a few simple observations a parent can gather before the appointment.

Abdominal pain in children: where to start

It is more useful to answer five questions than to hunt for a diagnosis:

1. Where it hurts — and, crucially, whether the pain moved.
2. How the child behaves: running and playing, or lying still with knees drawn up.
3. What else is present: fever, vomiting, diarrhoea, absent stool.
4. Whether pain wakes the child at night or interrupts play.
5. What stool and urine have done in the past day.

A child bouncing around the room almost never has a surgical catastrophe. A child lying still who will not let you touch the abdomen has one until proven otherwise.

Appendicitis symptoms in children and why it gets missed

The classic picture: pain starts around the navel, then after some hours shifts to the right lower quadrant, intensifies, and is joined by nausea, loss of appetite and a modest fever. Pain worsens with walking, jumping and coughing — the child walks bent over.

The problem is that in children this sequence is often broken:

• under 3–5 years appendicitis can look like an intestinal infection, with diarrhoea, vomiting and fever;
• with a pelvic appendix, pain radiates low and comes with urinary frequency;
• with a retrocaecal one, the loin and right flank hurt while the abdomen stays soft;
• in young children perforation happens faster than in adults, because the omentum does not wall the inflammation off.

Hence the simple rule when appendicitis is suspected: a surgical review, not observation at home. A classic trap is the pain disappearing: if severe pain suddenly stops and the child becomes limp and pale, that may mean perforation rather than recovery.

Abdominal pain without fever in children

No fever makes infection less likely and brings other causes forward: constipation — the commonest and most underestimated; overeating and food intolerance; worms, see enterobiasis and testing for worms; gastritis and its causes, see gastritis and Helicobacter; and in school-age children functional pain (below). A chronic course with poor weight gain prompts exclusion of coeliac disease.

Separately: in children a urinary tract infection often presents as abdominal pain rather than urinary complaints — which is why a urinalysis belongs in the basic set.

Pain around the navel in children: what it means

A peri-umbilical location is the commonest in children and usually a favourable sign: visceral pain pathways converge there, so pain of any origin projects to that spot, functional pain included. The rule paediatricians use: the further the pain from the navel, the more serious it is. Pain pointed to precisely with one finger in the right lower quadrant is more worrying than diffuse pain "somewhere around the belly button".

Functional abdominal pain in children: when it is not a disease

If a child aged 5–15 complains regularly for months while growing and gaining weight, with no night waking from pain, no blood in stool and no fever, this is most likely functional abdominal pain. It is real: what changes is the sensitivity of the gut wall and signal processing, not the child's imagination. The gut-state connection is covered in microbiome and anxiety.

Such pain often tracks school, anxiety and conflict; in some children chronic stress sits behind it, as described in childhood trauma. Importantly, functional pain is a positive diagnosis by criteria, not "we investigated and found nothing". Endless further testing harms here: it entrenches the child's belief that they are seriously ill.

Stomach pain and vomiting in children: worrying combinations

• pain + green (bilious) vomit — suspected obstruction, urgent;
• pain + vomiting + no stool or flatus — the same;
• colicky pain in a child under 2 with screaming, drawn-up legs and redcurrant-jelly stool — the picture of intussusception, measured in hours;
• pain + vomiting + high fever — possible appendicitis or another surgical cause, see also fever in children;
• pain after abdominal injury — mandatory review even if the child seems well.

When abdominal pain is dangerous: red flags

• pain lasting more than 4–6 hours and worsening;
• pain that has shifted to the right lower quadrant;
• a rigid abdomen the child will not let you touch;
• pain that wakes at night or interrupts play;
• blood in stool or vomit;
• weight loss, faltering growth, prolonged fever;
• pain in a child under 2 who cannot explain what is happening.

What to do at home and which tests are needed

Before assessment: give no painkillers (they erase the very picture a surgeon decides on), no hot-water bottle (heat fuels inflammation), no laxatives or enemas when obstruction is suspected, and no food while pain is severe. Sips of water are allowed.

The basic workup for unclear pain: a complete blood count with differential — paediatric ranges are in CBC in children; CRP as an inflammation marker; a urine test; and abdominal ultrasound when a surgical cause is suspected. No single test confirms or excludes appendicitis — the surgeon decides on the whole picture.

If pain recurs over months and you want to assemble the full picture — what, when, with what, and what precedes it — that is exactly what the symptom analysis service is for.

This article is informational and does not replace examination. Acute abdominal pain needs a doctor.