Fever in children: when to wait, when to call

Fever is one of the most common reasons parents call a doctor. This guide explains what it means and when it needs attention.

What is a fever?

A fever is usually a body temperature of 38 °C (100.4 °F) or higher; measured under the armpit, about 37.5 °C (99.5 °F) or higher counts as fever. It is a sign that the body is fighting something, most often a viral infection, rather than an illness on its own. A child with a fever who is drinking, playing between fevers and looking comfortable is usually less of a concern than the number on the thermometer suggests.

Measuring it

• Use a digital thermometer under the armpit for children, and follow the maker's instructions for babies.
• Do not judge by touch alone.
• Write down the temperature and the time; your doctor will want to know how the fever has behaved.

What helps at home

• Offer fluids often: breast milk, formula, water or oral rehydration solution.
• Dress your child in light clothing and keep the room comfortable.
• Paracetamol can ease discomfort. The dose depends on your child's weight, so ask your doctor for the correct dose. Do not give aspirin to children.
• Do not use cold water or alcohol sponging.

When to see a doctor promptly

• Any fever in a baby under 3 months of age.
• A fever that has lasted more than 3 days.
• Your child is unusually sleepy, hard to wake or very irritable.
• Fast or difficult breathing.
• A seizure.
• Repeated vomiting, refusing to drink, or passing very little urine.
• A stiff neck, a severe headache, or a rash that does not fade when pressed.
• Your child just looks very unwell, even if the number is low.

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