A child with a temperature: what we actually look at

Parents almost always lead with the number. Thirty-nine point two. Thirty- eight point eight since Tuesday.

I understand why — it is the one measurable thing available at eleven at night. But height of fever correlates poorly with how serious the underlying illness is. A child can have forty degrees with a virus that resolves in three days, and can be seriously unwell at thirty-seven point eight.

What we look at instead is the child.

What we are actually assessing

Behaviour. Is the child interacting? Responding to you normally? A child who smiles, protests at being examined, or is annoyed with me is giving me a great deal of reassurance. Abnormal drowsiness, or a cry that does not sound right to you, is the opposite.

Breathing. Rate, effort, and whether the spaces between and below the ribs are being pulled in. Working hard to breathe matters far more than temperature.

Colour. Pale, mottled, blue or ashen is significant. Flushed with fever is not.

Hydration. Wet nappies, fluid going in, moist lips, and whether the tears are still there when they cry.

Rash. Specifically whether it fades under pressure. Press a glass against it. A rash that does not blanch is an emergency.

What should bring you in, or to hospital

Go straight to an emergency department, or call 999, for any of: a rash that does not fade under pressure; difficulty breathing or grunting; a child who is floppy, unrousable or will not wake properly; a seizure; a fever in a baby under three months; or a neck that is stiff with a dislike of light.

Call us the same day for: a fever lasting more than five days; fewer than half the normal wet nappies; a child who is not improving at all; pain that is not controlled; or — and I mean this entirely seriously — if you are worried in a way you cannot articulate.

On that last point

Parental concern is a documented, independent predictor of serious illness in children. It performs better than several of the things we measure.

You know what your child is normally like, in a way that no clinician seeing them for the first time can. When a parent says “he’s just not himself”, I pay close attention to that sentence, and I would far rather see forty children who turn out to be fine than miss the one who was not.

Nobody has ever wasted my time by bringing in a child.