Fever - Without source


These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

Read the full PCH Emergency Department disclaimer.


To guide staff with the assessment and management of fever without a source.


Fever without source (FWS):  A child or infant presenting with a fever >38C (axillary or rectal) without a readily identifiable source on history and/or physical examination (e.g. no coryzal or other respiratory signs/symptoms).1 Fever is nature’s way of killing viruses / bacteria.

Key points

  • Fever > 38oC in the 3-6 month age group is concerning as they are not fully immunised.
  • After 6 months of age the height of the fever is unhelpful.
  • Most fevers are caused by a viral illness.
  • Lack of response to antipyretics does not predict a serious illness.

Fever without a source flowchart

Please click on the image to download the PDF version.

Fever without source management flowchart. Click to enlarge.


  • General features of the child’s behaviour, interaction and appearance over a period of time provide the best indicator of whether serious infection is likely
  • Beware of the unimmunised child
  • Beware of the partially treated child.


System for identifying the likelihood of serious illness2

  Low risk (Green) Medium risk (Amber) High risk (Red)
Colour activity  Normal colour
Responds normally to social cues
Content/smiles, stays awake or awakens quickly
Strong normal cry/not crying  
Pallor reported by parents/carers
Not responding normally to social cues
No smile
Wakes only with prolonged stimulation 
No response to social cues
Appears ill to a healthcare professional
Does not wake or if roused does not stay awake
Weak high pitched cry or continuous cry 
Respiratory  Normal parameters
No respiratory distress 
Nasal flaring
Sp02 ≤95%, Crackles in chest
Moderate to severe chest in drawing
Circulation and hydration  Normal skin and eyes
Moist mucous membranes 
Capillary reduce time ≥3 seconds
Dry mucous membranes
Poor feeding in infants
Reduced urine output 
Reduced skin turgor 
Other  None of the amber or red symptoms or signs  Age 3-6 months, temp ≥ 39°C
Fever for ≥ 5 days
Swelling of a limb or joint
Non-weight bearing limb/not using an extremity

Age <3 months, temp ≥ 38°C
Non blanching rash 
Bulging fontanelle 
Neck stiffness
Status epilepticus
Focal neurological signs
Focal seizures

Normal Paediatric Values

See Emergency Calculator (internal use only) to view normal heart rate, respiratory rate and blood pressure values.


Neonates with a temperature >38°C

  • FBC, U&E, CRP and blood cultures
  • Urine (SPA specimen)
  • Lumbar puncture
  • Consider CXR if indicated
  • Admit for empiric IV antibiotics.

1 Month - 3 months of age with a temperature >38°C

  • FBC, U&E, CRP, blood cultures
  • Urine (catheter or SPA specimen)
  • Consider lumbar puncture (determined by clinical condition)
  • Consider CXR
  • Admit under General Paediatric team for IV antibiotics

>3 months of age with a temperature of >38°C

Sick looking child:

  • FBC, U&E, CPR, blood cultures
  • Urine (clean catch or catheter)
  • Consider lumbar puncture (determined by clinical condition)
  • Consider CXR
  • Admit under General Paediatric team for IV antibiotics

Well looking child:

  • Obtain urine as per Urinary Tract Infection guideline
  • Unsure: Use the Low, Medium, High Risk System to assess and seek Senior Medical advice to guide investigations and treatment. 


Use the Low, Medium, High Risk system to assess and seek Senior Medical advice to guide investigations and treatment.

Lumbar puncture

Unless contraindicated (see ED Lumbar Puncture guideline), consider LP if: 

  • Toxic
  • Irritable
  • Suspected meningitis or encephalitis
  • Unimmunised
  • Partially treated
  • Use caution if a patient who presents with a complex febrile convulsion and does not return to normal behaviour may have a meningoencephalitis and should be treated empirically. A lumbar puncture should be deferred until it is safe to perform.

For further information regarding lumbar punctures refer to Lumbar Puncture.

Chest X-ray

Usually only considered if signs of respiratory illness:

  • Cough
  • Increased respiratory rate
  • Crepitations or dullness on auscultation
  • Decreased oxygen saturations.



  • 15 mg/kg 4-6 hourly 
    • Maximum 60mg/kg/day for < 3 month old child 
    • Maximum 80mg/kg/day for > 3 month old child.


  • 10mg/kg (maximum 400mg) 6-8 hourly4 for > 3 month old child
  • Maximum 30mg/kg (maximum 2.4g) daily may be used in the short term4. Give with food.

Health information (for carers)

  • Fever does not cause brain damage
  • Use of antipyretics does not prevent febrile convulsions
  • Do not use antipyretics for more than three days without a General Practitioner review
  • Advise parents and document the features they need to look out for at home and when to seek further advice
  • Provide Health Fact Sheet: Fever in Children


  1. Gómez B, Mintegi S, Benito J, Egireun A, Garcia D, Astobiza E. Blood culture and bacteremia predictors in infants less than three months of age with fever without source. The Pediatric infectious disease journal. 2010;29(1):43-7.
  2. Neonatal Directorate Guidelines. Sepsis Calculator – Assessment of Early onset Sepsis in Infants >35weeks. 2019. Available from https://www.kemh.health.wa.gov.au/~/media/Files/Hospitals/WNHS/For%20health%20professionals/Clinical%20guidelines/NEOPN/WNHS.NEOPN.SepsisSepticCalculatorAssessmentofEarly-OnsetSepsisinInfantsmore35Weeks.pdf
  3. Textbook of Paediatric Emergency Medicine 2nd Edition Cameron Elesevier 2012
  4. Bonita M.D. Stanton, Joseph St. Geme, Nina F Schor. Nelson Textbook of Pediatrics: 20th Edition Robert M. Kliegman, Publisher: Elsevier
  5. NICE clinical guideline NG143. Fever in Under 5s: Assessment and Initial Management. November, 2019.
  6. Craig JC, Williams GJ, Jones M, Codarini M, Macaskill P, Hayen A, Irwig L, Fitzgerald DA, Isaacs D, McCaskill M. The accuracy of clinical symptoms and signs for the diagnosis of serious bacterial infection in young febrile children: prospective cohort study of 15 781 febrile illnesses. BMJ. 2010;340:c1594. Epub 2010 Apr 20.
  7. AMH Children’s Dosing Companion. Paracetamol. Australian Medicines Handbook Pty Ltd
  8. AMH Children’s Dosing Companion. Ibuprofen. Australian Medicines Handbook Pty Ltd

Endorsed by: Co-Director, Surgical Services  Date: May 2020

 Review date:  May 2023

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