The Febrile Child

Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

  • Urinary Tract Infection
  • Bronchiolitis
  • Croup
  • Common Viral Exanthems (e.g. Chickenpox, Roseola, Hand, Foot and Mouth, Fifth Disease)
  • Appendicitis
  • Cellulitis (Especially Orbital) and other Significant Skin Infections (e.g. Abscess, Scalded Skin)
  • Glandular Fever
  • Post-Immunisation
  • Giardiasis

Rare Diagnoses

  • Meningitis/Meningococcal Septicaemia
  • Encephalitis
  • Hepatitis
  • AIDS
  • Rare Exanthems (e.g. Measles, Rubella)
  • Mumps
  • Acute Epiglottitis
  • Atypical Infections (e.g. Brucellosis, Listeriosis, Lyme Disease, Cat Scratch Fever)
  • Tuberculosis
  • Protozoal Diseases (e.g. Cryptosporidium, Leishmaniasis, Toxoplasmosis, Malaria)
  • Septic Arthritis, Osteomyelitis
  • Kawasaki’s Disease

Ready Reckoner

Key distinguishing features of the most common diagnoses

URTIGastroenteritisOMTonsillitisChest Infection
Prominent Neck NodesPossible NoPossibleYesPossible
Significant Pain NoPossibleYesYesPossible
Localising Chest Signs No No No NoYes
CoughYesNoPossible NoYes

Possible Investigations

  • Usually none are necessary in practice. If a febrile child is ill enough to require investigation, the problem will usually be sufficiently urgent to need management by acute admission. Urinalysis, as a pointer to UTI (assuming obtaining a urine sample is feasible), is sometimes helpful in avoiding or facilitating admission. If possible, extend this to an MSU for bacteriological analysis.

Top Tips

  • Many clinical markers (see Ready reckoner) are non-specific and are present in many different infections. It is often a matter of degree as to how likely they are a pointer to a specific pathology. For example, many infections cause mesenteric adenitis with abdominal pain, but the tenderness of appendicitis, for example, is usually far greater on examination. Respiratory rate is raised in all fevers, but a chest problem will increase it further along with the presence of chest signs. A good policy is to be as thorough as possible in an examination so as to be able to cross-reference the maximum clinical information.
  • Remember that parents will be worried about their child, and no matter how simple the management of this common problem appears to you, to the parent it may be the harbinger of a serious illness. Practise a calm and polite demeanour, empathy and sensitivity.
  • In telephone advice calls, always do three things: First, check that the parent is satisfied with your advice; second, put a robust safety net/plan B in place with easily identifiable guidelines for the parent, e.g. ‘if by X hours Y has not happened, then call back’; third, record your clinical assessment and the last two points in detail.
  • If in doubt, always see a child in person. Be sensitive to your intuition. If something nags you after an advice call, ring back and arrange a consultation. You will never look stupid for doing this – only careful.
  • Remember to follow up with children in whom you’ve diagnosed UTI according to NICE guidelines, which recommend further investigation, varying according to the age of the child.
  • It is very easy to print computerised clinical notes immediately after writing them. Handing a consultation note to a parent can be invaluable to the parent (and the clinician) if the child is seen later on out of hours, when clinical records are often unavailable. The baseline findings from earlier in the day can be priceless information in the dark hours later on.
  • Spend time explaining the nature of fever and that the key issue is the cause of the fever rather than the fever itself – many parents are ‘fever phobic’.
  • It’s often more important to be able to distinguish between ‘well’ and ‘ill’ babies and children than it is to make a clever, precise diagnosis – the NICE ‘traffic light’ and sepsis guidance may help.
  • It’s easy to be tempted into complacency in the telephone or consultation management of this problem – fever is just so common. Never forget that uncommon very serious illnesses may all begin with a fever. Always be diligent and systematic in assessment, no matter how busy your winter on-call day is turning out to be.

Red Flags

  • Dehydration can kill a baby quickly. Ensure you have satisfied yourself about the state of hydration of a child. The colour and quantity of urine passed, or frequency of nappy changes are useful practical guides, together with the general ‘look’ of the child and the capillary refill time.
  • A febrile baby or child who is floppy or drowsy should be admitted immediately.
  • Be suspicious of the irritable and inconsolable infant. Even without other hard evidence, suspect a serious problem and arrange urgent paediatric assessment.
  • The petechial rash of meningococcal septicaemia is a late phenomenon. Do not be reassured by its absence. Its presence should prompt a 999 call and administration of immediate parenteral antibiotics according to local protocols.
  • In most cases, the height of a fever is no guide to the severity of the illness – the exception being babies, where a temperature of 38°C or more in those under 3 months is seen as a ‘red’ and one of 39°C or more in those between 3 and 6 months is viewed as ‘amber’ according to NICE.
  • Don’t forget malaria as a possibility, especially if there is otherwise no clear explanation for a fever – enquire about recent foreign travel.

Published: 2nd August 2022 Updated: 10th April 2024

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