When to Call Your GP About a Baby Fever

What counts as a fever

• Under 3 months: 38°C (100.4°F) or higher — always a reason to call, no matter how well they seem.
• 3–6 months: 39°C (102.2°F) or higher is the "always call" threshold.
• Over 6 months: the number matters less than how they seem. A 39°C baby playing happily needs a different response than a 38°C baby who's floppy and grey.

Always use a digital thermometer under the arm for babies. Forehead scanners are okay-ish for a general sense, but under-arm readings are what a GP will trust.

Call 111 (UK) or your paediatrician (US) now if…

Any of the red-flag signs above, plus:

• The fever is over 5 days old, or came back after 24 hours of being gone
• They've had a febrile convulsion (seizure with a high temperature)
• You feel that something is wrong — even if you can't say what. Parental gut counts.

The glass test for a rash

Press the side of a clear glass firmly against the rash. If the rash fades under the pressure, it's a typical viral rash. If it doesn't fade (stays visible through the glass), that can be a sign of meningococcal septicaemia — 999 (UK) / 911 (US) immediately.

What you can do while you wait or decide

• Strip a layer of clothes but don't cold-sponge them — that constricts blood vessels and can spike the temperature.
• Offer small, frequent fluids — breast, bottle, cooled boiled water for over-6-month-olds, or their usual milk.
• Infant paracetamol or ibuprofen per the packet dosing for their weight and age, if they're distressed. It won't cure the illness; it takes the edge off so they can rest.
• Keep them close, in a cool room. Skin-to-skin is a reliable comfort.
• Write down when the fever started, the highest reading, other symptoms, and what fluids they've had. This is exactly what 111 or the GP will ask.

The Elira way to prep for a call

Before you dial, jot down (or dictate into your phone):

1. Age in months, weight (rough is fine)
2. Highest temperature and when it was measured
3. How long they've been unwell
4. Other symptoms (rash, cough, vomiting, feeding, wees)
5. Any medication given and when

Two calm minutes of prep will make the whole call twice as useful. If you use Elira's Doctor Visit Prep feature, it walks you through this in about 90 seconds.

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I'm Elira — a wellness companion, not a doctor. This guide is for reflection and gentle support, not medical advice. If something feels wrong, trust your gut and speak to your GP, health visitor, or 111 (UK) / your paediatrician (US).