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Fever in babies
Overview
Fever in babies is a symptom rather than one diagnosis. The child’s age, associated signs and overall condition determine the likely causes and urgency.
This guide provides general education and cannot diagnose an individual or replace professional assessment.
Signs and symptoms
A measured temperature of 38°C or higher is a fever. Babies may also feed less, become unusually sleepy or irritable, or breathe differently.
Age, development, duration, severity and impact on daily life help determine what the symptom means.
Causes
Common causes include minor infection, normal variation, environment, hydration and temporary stress, but persistent symptoms can reflect an underlying condition.
Risk factors
Very young age, chronic illness, recent injury, medicine use, travel, exposure and reduced immunity can increase concern. Risk factors do not confirm a diagnosis.
Diagnosis
A clinician uses the history, examination and growth or vital signs, choosing tests only when they can clarify the cause.
Treatment options
Care targets the cause rather than the symptom alone and may include fluids, comfort measures, medicine or specialist referral.
Home care
Record temperature or episodes accurately, encourage fluids and avoid combining medicines or using products unsuitable for the child’s age.
Prevention
Healthy routines, hydration, hygiene, dental care, safe environments and management of known conditions prevent some causes.
Possible complications
The main risk is missing a serious underlying illness or allowing dehydration, infection or functional difficulty to worsen.
When to seek urgent medical care
A baby under 3 months with a temperature of 38°C or higher needs urgent medical assessment. Seek emergency help for breathing difficulty, non-fading rash, seizure or reduced responsiveness.
Call emergency services for severe breathing difficulty, blue or grey colour, collapse, reduced responsiveness, uncontrolled bleeding or rapidly worsening serious illness.
Frequently asked questions
Should we wait and see?
Brief mild symptoms can sometimes be observed, but new, severe, persistent or worsening symptoms deserve professional advice.
What should I record?
Note timing, triggers, duration, associated symptoms, medicines, sleep and the effect on eating, drinking, movement, learning or family life.
Who should assess this?
Start with the child’s primary-care clinician, dentist, optometrist, hearing professional, maternity professional or mental-health clinician as appropriate. Emergency warning signs need urgent services.
Summary
Age and overall condition make fever in a young baby particularly important to assess.
References
OUR REVIEW PROMISE
Evidence-based, clearly reviewed.
Healthier Baby Today articles are reviewed for accuracy and updated as guidance changes.
Last updated: July 17, 2026
