How should I assess the risk of serious illness in a febrile child under 5 years presenting in primary care?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

To assess the risk of serious illness in a febrile child under 5 years, healthcare professionals should use the NICE traffic light system, which involves evaluating clinical features such as skin colour, activity level, respiratory rate, oxygen saturation, circulation, hydration, and specific symptoms .

Assess the child's general appearance, temperature, heart rate, respiratory rate, capillary refill time, and fluid status if seen face-to-face .

Identify any 'red' features indicating an immediately life-threatening illness, such as signs of sepsis, bacterial meningitis, herpes simplex encephalitis, pneumonia, urinary tract infection, septic arthritis, or Kawasaki disease, and refer urgently if present .

Children with 'amber' features but no 'red' features should be assessed promptly, with clinical judgment guiding the urgency, and safety nets provided if diagnosis remains uncertain .

Use the presence of clinical signs such as abnormal skin colour, abnormal breathing, circulation, hydration status, and specific symptoms to stratify risk into green (low), amber (intermediate), or red (high) categories .

Educational content only. Always verify information and use clinical judgement.