Synopsis
Assess a febrile child by age, physiology and clinical appearance, identify serious bacterial or inflammatory disease early, investigate in a risk-directed sequence, and give families practical treatment and safety-netting advice.
- Fever is a temperature of 38°C or higher, but severity is determined by age, appearance and physiology rather than the height of temperature alone after 6 months.
- First priority is airway, breathing, circulation, consciousness and glucose. Ask immediately whether the child could have sepsis and use the age-specific NICE risk table.
- Measure temperature electronically in the axilla under 4 weeks. From 4 weeks to 5 years, use electronic or chemical-dot axillary measurement, or an infrared tympanic thermometer.
- Record heart rate, respiratory rate, capillary refill, hydration, alertness and oxygen saturation; measure blood pressure when heart rate or capillary refill is abnormal and suitable equipment is available.
- Under 3 months, 38°C or higher is high risk. At 3 to 6 months, 39°C or higher is at least intermediate risk. Temperature alone is not a reliable severity marker in older infants and children.
- Use the NICE traffic-light system: any red feature means high risk; amber without red means intermediate risk; only children with no amber or red feature are low risk.
- Look deliberately for urine infection, pneumonia, meningitis, meningococcal disease, septic arthritis or osteomyelitis, Kawasaki disease and travel-associated infection rather than labelling fever as viral by default.
- Every febrile infant under 3 months needs specialist observation and blood count, blood culture, C-reactive protein and urine testing; lumbar puncture and parenteral antibiotics depend on exact age and illness features.
- At 3 months or older with fever without source, red features require blood count, culture, C-reactive protein and urine testing; amber features normally require urine and blood tests unless an experienced paediatrician decides otherwise.
- Do not use response to paracetamol or ibuprofen to distinguish serious from non-serious infection. Reassess amber or red hospital presentations after 1 to 2 hours regardless of temperature response.
- Use either paracetamol or ibuprofen only when the child is distressed, not simply to normalise temperature. Do not give both together; consider changing agent, and alternate only if distress recurs before the next dose is due.
- Discharge only when risk, trajectory, hydration, family circumstances and follow-up are safe. Give written red flags and advise regular observation, including overnight.
Key red flags
Any infant younger than 3 months with a measured temperature of 38°C or higher is at high risk of serious illness and needs urgent clinical assessment.
A child aged 3 to 6 months with a temperature of 39°C or higher is at least intermediate risk, even when the initial appearance seems reassuring.
Pale, mottled, ashen or blue colour; failure to wake or stay awake; weak high-pitched cry; grunting; marked chest indrawing; reduced skin turgor; or a bulging fontanelle is a NICE red feature.
A non-blanching rash, neck stiffness, focal seizure, focal neurological sign or status epilepticus requires emergency assessment for meningococcal disease, meningitis or encephalitis.
Fever for 5 days or longer requires assessment for Kawasaki disease, including asking about earlier conjunctival, oral, rash, limb and cervical-node changes that may have resolved.
Impaired immunity, recent surgery, an indwelling device, recent travel, safeguarding concern or repeated caregiver presentation lowers the threshold for investigation and paediatric review.
Investigation priorities
Identify immediate instability and assign the age-specific NICE risk category.
Detect occult invasive or urinary bacterial infection in a high-risk age group.
Management branches
The child has shock, impaired consciousness, meningococcal signs or another immediately threatening feature.
- Activate senior paediatric help and manage airway, breathing, circulation, glucose and temperature concurrently.
- Take blood culture and source specimens if this causes no delay, then give immediate age-appropriate parenteral antimicrobials.
- Give 10 mL/kg isotonic crystalloid for shock with active reassessment, and escalate early to critical care when perfusion or breathing does not respond.