Fever in Children: When to Worry, When to Wait, and How to Manage It

What is a fever?

A fever is a body temperature above:

• 38°C (100.4°F) in infants under 3 months
• 38.5°C (101.3°F) in older infants and children

Fever is not a disease: it is the immune system's response to infection. A moderate fever actually helps fight pathogens by creating an inhospitable environment for bacteria and viruses.

How to measure accurately

Under 3 months: Rectal temperature is the gold standard.

3 months–4 years: Rectal, axillary (armpit), or tympanic (ear): each has different normals:

• Rectal: add 0°C (it is already the internal temperature)
• Axillary: may read 0.5–1°C lower than core
• Ear: can be inaccurate if not used correctly

Over 4 years: Oral or tympanic.

Forehead strips are not reliable for clinical decision-making.

When to seek emergency care immediately

Call 999/112 or go to A&E if:

• Under 3 months with ANY fever ≥38°C
• Rash that doesn't fade when pressed (glass test: may indicate meningitis)
• Difficulty breathing, grunting, or ribs visibly pulling in
• Seizure for the first time, or lasting >5 minutes
• Sunken fontanelle (soft spot on head), or extremely stiff neck
• Unresponsive, floppy, or very difficult to wake
• Persisting fever over 40.5°C (105°F)

When to call your doctor

• 3–6 months with fever ≥38°C
• Fever lasting more than 5 days at any age
• Fever returning after more than 24 hours without fever
• Child appears very unwell even after medication brings fever down
• Parents are concerned regardless of temperature

Managing fever at home

Medication

• Paracetamol (acetaminophen): Safe from birth, every 4–6 hours as needed
• Ibuprofen: From 3 months (check weight-based dosing), every 6–8 hours
• Do not give aspirin to children (risk of Reye's syndrome)
• Do not alternate paracetamol and ibuprofen routinely

Comfort measures

• Dress lightly: overheating increases discomfort
• Ensure good fluid intake (breastmilk, formula, or water/diluted juice for older children)
• Cool (not cold) flannel on forehead if child is comfortable with it
• Cool sponging is not routinely recommended (causes shivering which raises temperature)

The good news

Most childhood fevers are caused by viral infections and resolve within 3–5 days without treatment. A fever that is responding to paracetamol and producing a child who is drinking, somewhat playful, and not showing red flags is usually reassuring.

---

The Childhood Journal provides general evidence-based information. Always consult your paediatrician for concerns specific to your child.