When should a child see a doctor for a fever?
Last updated September 3, 2026.
Any baby under 3 months with a temperature of 38C (100.4F) or more needs urgent assessment, and 3 to 6 months at 39C (102.2F) or more - young infants can be seriously ill without looking it. Also get same-day help for fever with a non-blanching rash, unusual drowsiness or floppiness, dehydration signs (few wet nappies, no tears), fast or labored breathing, refusing fluids, a seizure, or a fever reaching five days. Behavior beats the number: a drinking, playing child at 38.5C worries less than a listless one at 38C. At home: fluids, light clothing, weight-dosed paracetamol or ibuprofen - never aspirin under 16. Pymander is a free AI doctor, 24/7 by text, and can walk through the checks for your child's age.
What to do
- Memorize the age cutoffs: under 3 months at 38C, 3 to 6 months at 39C - urgent care.
- Do the glass test on any rash: a rash that does not fade under pressure is an emergency.
- Judge behavior, not just degrees: drinking, smiling, and playing are reassuring signs.
- Dose medicine by weight: paracetamol or ibuprofen for comfort; never aspirin under 16.
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