The febrile child
Most feverish children have a simple viral illness. Your job is to find the few with serious infection, using the traffic light signs, the age, and a urine test, and to treat the child, not the number.
A 9-month-old boy has had fever of 39.5 °C for 2 days. His mother says he is feeding less. He is smiling at you from her lap, pink, with capillary refill under 2 seconds. Heart rate 140, RR 36. No rash. No obvious source on examination.
Is he safe to go home, and what test must not be missed?
- Look from the doorwayPlaying, smiling and alert, or floppy, pale and quiet?
- Full observationsHeart rate, RR, capillary refill, SpO₂, temperature.
- Grade with the traffic lightGreen, amber or red (see below).
- Look for a sourceEars, throat, chest, skin, joints, neck stiffness, fontanelle.
- Always test the urineIn any child with fever and no clear source.
- Under 3 monthsFever of 38 °C or more is high risk: full septic screen and antibiotics.
- Sick childFollow Sepsis in children.
- Safety-net the parentsClear advice on when to return.
- Under 3 months with temperature 38 °C or more
- Non-blanching rash
- Pale, mottled, ashen or blue
- Will not wake, or will not stay awake
- Weak, high-pitched or continuous cry
- Grunting, RR above 60, bulging fontanelle, fits
- Meningococcal disease
- Bacterial meningitis or encephalitis
- Sepsis
- UTI
- Kawasaki disease
- Septic arthritis
- Malaria, typhoid, dengue or pneumonia
| Under 3 months, 38 °C or more | High risk. Septic screen and IV antibiotics |
| Paracetamol | 15 mg/kg every 4–6 hours, max 60 mg/kg/day, for distress |
| Ibuprofen | 10 mg/kg every 6–8 hours (over 3 months). Not in dengue or dehydration |
| Fever over 5 days | Think Kawasaki disease, typhoid, TB, malaria |
| Fluid bolus if shocked | 10 mL/kg, reassess |
Check every dose against a current drug reference and your hospital protocol.
On this page
The traffic light (NICE)
- Normal colour
- Responds normally, smiling, stays awake, strong cry
- No amber or red features
- Usually home with advice
- Pale (reported)
- Reduced activity, not smiling
- Nasal flaring, RR raised, SpO₂ 95% or less, crackles
- Fast heart rate, capillary refill 3 seconds or more, dry mouth, poor feeding, less urine
- Fever 5 days or more, swollen limb or joint, rigors
- Assess carefully, senior review, safety-net or admit
- Pale, mottled, ashen or blue
- No response, does not wake, weak or continuous cry
- Grunting, RR above 60, severe recession
- Reduced skin turgor
- Under 3 months 38 °C or more
- 3–6 months 39 °C or more
- Non-blanching rash, bulging fontanelle, neck stiffness, fits, focal signs
- Admit, senior review now
Age matters
- Under 3 months: fever of 38 °C or more needs a full septic screen (blood culture, CBC, CRP, urine, and lumbar puncture if indicated) and IV antibiotics. Babies show few signs.
- 3–6 months: 39 °C or more is a red feature.
- Height of fever alone is not a good guide in older children. How the child looks matters more.
Look for the source
| Source | Look for |
|---|---|
| Ears and throat | Red bulging eardrum, tonsillitis |
| Chest | Fast breathing, crackles, low SpO₂ |
| Urine | Always test: a common hidden source, especially in babies and girls |
| Skin and joints | Cellulitis, non-blanching rash, a hot swollen joint or a child not using a limb |
| Meninges | Neck stiffness, bulging fontanelle, irritability, drowsiness |
| Belly | Tenderness, typhoid |
Infections common in Pakistan: dengue (season, low platelets), typhoid (fever over a week), malaria (endemic areas), pneumonia, measles (rash, cough, red eyes, unvaccinated).
Fever lasting 5 days or more
Think of Kawasaki disease: fever with red eyes (no discharge), red cracked lips and strawberry tongue, rash, swollen red hands and feet, a large neck lymph node. Early treatment with IV immunoglobulin protects the coronary arteries. Also typhoid, TB, malaria, UTI, abscess.
Treatment
Treat the child, not the thermometer. Antipyretics make a child more comfortable but do not prevent febrile convulsions. Do not alternate paracetamol and ibuprofen routinely. Do not give antibiotics "to be safe" to a well child with a viral illness.
- Tepid sponging is not recommended: it makes children uncomfortable without helping.
- Do not wrap a feverish child in blankets.
Safety-netting
- Has a fit.
- Develops a rash that does not fade under a glass.
- Becomes floppy, drowsy, or hard to wake.
- Has fast or difficult breathing, or grunting.
- Stops drinking, or has very few wet nappies.
- Has fever for 5 days or more.
- Is getting worse, or the parents are worried.
Common mistakes
- Not testing the urine.
- Sending home a feverish baby under 3 months.
- Relying on the temperature falling with paracetamol as proof the child is not seriously ill.
- Antibiotics for every fever.
- Missing Kawasaki disease after 5 days of fever.
- Ibuprofen in dengue season without thinking.
Frequently asked questions
When is fever in a child an emergency?
Any fever of 38 °C or more in a baby under 3 months, or any child with red traffic-light features: pale, mottled or blue skin, not responding, grunting or very fast breathing, non-blanching rash, bulging fontanelle, neck stiffness or fits.
What is the paracetamol dose for children?
15 mg/kg every 4–6 hours, up to 4 doses (60 mg/kg) in 24 hours.
Should every feverish child have a urine test?
Every child with fever and no clear source should have a urine test, because urinary tract infection is a common hidden cause.
When should I worry about fever in a baby?
Any temperature of 38 °C or more in a baby under 3 months, or any child who is pale, mottled or blue, hard to wake, has a weak or continuous cry, grunting, a non-blanching rash, a bulging fontanelle, fits, or fever lasting 5 days or more.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A 6-week-old baby has a temperature of 38.2 °C and is feeding well. What is the best plan?
Answer: Septic screen, IV antibiotics. Infants under 3 months with fever need a full septic screen and IV cefotaxime or ceftriaxone, plus amoxicillin in the first weeks.
- Paracetamol and home: Under 3 months with fever is high risk.
- Observe at home 24 hours: Unsafe.
- Oral amoxicillin: Not sufficient.
- Urine test only: Not enough under 3 months.
2. A 9-month-old has fever 39.5 °C, is smiling and pink with normal capillary refill and no source. What test is most useful?
Answer: A clean-catch urine test. Urinary infection is the commonest serious bacterial infection in febrile infants without a source.
- Lumbar puncture: Not in a well child.
- Chest X-ray in all: Not needed if chest is clear.
- CT head: No.
- Blood culture only: Urine first.
3. A child has had fever for 6 days with red eyes, cracked lips, a rash and swollen hands. What is the likely diagnosis?
Answer: Kawasaki disease. Kawasaki disease: fever for 5 days or more plus mucosal changes, conjunctivitis, rash, extremity changes and lymph nodes. Echo and IV immunoglobulin.
- Viral exanthem: Too many specific features.
- Scarlet fever: Not with conjunctivitis and swollen hands.
- Dengue: Different.
- Measles: Different pattern; would have cough and Koplik spots.
4. A 9-year-old has fever, migratory polyarthritis of large joints and a new apical pansystolic murmur 3 weeks after a sore throat. ASO titre is high. What long-term treatment is essential?
Answer: Benzathine penicillin 3–4 weekly. Acute rheumatic fever (Jones criteria) with carditis: treat with penicillin (eradicate strep), aspirin/NSAIDs for arthritis, and heart failure management. The key is secondary prophylaxis with IM benzathine penicillin every 3–4 weeks — with carditis for at least 10 years or until age 21–40 depending on severity — to prevent recurrences that worsen rheumatic heart disease (mitral regurgitation/stenosis).
- One 10-day course of amoxicillin: One course of amoxicillin treats the throat but does not prevent recurrence; long-term prophylaxis is needed.
- Long-term NSAIDs: NSAIDs relieve arthritis but do not prevent recurrent streptococcal infection.
- Oral penicillin for 1 year only: One year is too short; with carditis prophylaxis continues for years.
5. Which part of the brain directly controls autonomic reflexes and body temperature?
Answer: Hypothalamus. The hypothalamus integrates autonomic control: temperature, hunger, thirst, water balance (ADH), circadian rhythms and pituitary function. It acts through brainstem autonomic centres and the pituitary.
- Thalamus: A sensory relay station.
- Cerebral cortex: Higher functions; it can influence but does not directly control autonomic reflexes.
- Cerebellum: Coordinates movement.
- Basal ganglia: Control movement initiation.
6. At the start of a fever, the hypothalamic set point rises. What does the body do?
Answer: Vasoconstriction and shivering. Pyrogens (IL-1, IL-6, TNF) trigger prostaglandin E2 in the hypothalamus, raising the set point. The body now 'feels cold', so it constricts skin vessels and shivers until temperature reaches the new set point. When the fever breaks, vessels dilate and sweating starts. Paracetamol and NSAIDs block PGE2 production.
- Heavy sweating: Happens when fever breaks.
- Skin vasodilatation: Happens when fever breaks.
- Stopping heat production: Heat production increases.
- Lowering the metabolic rate: Metabolic rate rises.
References and dose sources
- NICE NG143: Fever in under 5s, assessment and initial management
- NICE NG240 — meningitis & meningococcal disease
- NICE NG254 — suspected sepsis in under 16s
- UKHSA — invasive group A strep
- NICE NG91
- NICE NG84
- UKHSA — scarlet fever
- NICE NG224 — UTI under 16s
- NICE NG9
- NICE NG138
- Paracetamol dosing: Drugs.com: Acetaminophen (paracetamol) dosage (see also our paracetamol dose page)
- Ibuprofen dosing: Drugs.com: Ibuprofen dosage (see also our ibuprofen dose page)
- Ceftriaxone dosing: Drugs.com: Ceftriaxone dosage (see also our ceftriaxone dose page)
- Amoxicillin dosing: Drugs.com: Amoxicillin dosage (see also our amoxicillin dose page)
- Aciclovir dosing: Drugs.com: Acyclovir (aciclovir) dosage (see also our aciclovir dose page)
- Ringer's lactate (Hartmann's solution) dosing: Drugs.com: Lactated Ringer's dosage (see also our ringer's lactate (hartmann's solution) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.