Child fever: when to see a doctor and when to care at home

A child fever worries many parents, and the big question is when to see a doctor. Most fevers settle on their own within a few days, but some signs mean a child needs to be seen straight away. This guide draws on the NHS and NICE (UK), the American Academy of Pediatrics (AAP) and the World Health Organization (WHO).

What counts as a fever?

According to the NHS and the AAP, a child has a fever when their temperature is 38°C or higher.

A fever is the body's natural response to fighting infection, such as coughs, colds, chickenpox or tonsillitis. Children can also get a fever after a vaccination. The NHS says the temperature usually returns to normal within 1 to 4 days.

How to take a child's temperature

The NHS recommends a digital thermometer under the arm. Place the tip high in the armpit, close the child's arm against their side, and hold it for as long as the instructions say. If the child has just had a bath or been wrapped in a blanket, wait a few minutes and measure again.

Advice by age differs between organisations:

The AAP considers a rectal reading the most accurate for babies under 3 months, while NICE advises against routinely using the mouth or rectum in children under 5. Ask your child's doctor which method suits your child. Do not use a mercury thermometer: it can break and release toxic mercury vapour (AAP). Forehead strips are less accurate (NICE, AAP).

Caring for a child with a fever at home

Do:

• Give plenty of fluids. If your baby is breastfed, keep breastfeeding as normal.
• Offer food if your child wants it.
• Watch for signs of dehydration: dry mouth, sunken eyes, no tears when crying, a sunken soft spot (fontanelle), fewer wet nappies than usual.
• Check on your child regularly, including at night.
• Keep your child at home and away from nursery or school while the fever lasts.

Don't:

• Don't undress your child completely, but don't wrap them in too many clothes or blankets either.
• Don't sponge them down, use ice packs or give alcohol baths to bring the temperature down. NICE does not recommend tepid sponging, and the AAP says these methods are no longer recommended because they can harm the child.
• Don't give aspirin to children under 16 unless a doctor prescribes it. The NHS says aspirin has been linked to Reye's syndrome, a rare but serious condition.

About fever medicine

NICE advises considering fever medicine only when the child seems distressed, not just to bring the temperature down, and notes that it does not prevent febrile seizures. Ask a doctor or pharmacist which medicine suits your child's age and weight, and how to use it.

NHS safety points: do not give paracetamol to a baby under 2 months; do not give ibuprofen to a child who is under 3 months, weighs under 5 kg, has chickenpox or is dehydrated; do not alternate paracetamol and ibuprofen unless a health professional tells you to.

NICE also notes that whether a fever comes down after medicine does not show whether the illness is serious.

By age: when to see a doctor

Babies under 3 months

NICE places babies under 3 months with a temperature of 38°C or higher in the high-risk group for serious illness. Contact a doctor or take your baby to a health facility straight away, even if you only think they have a fever and have not measured it (NHS). Even if your baby has just been vaccinated, let a health professional assess them rather than guessing.

Babies 3 to 6 months

NICE places babies aged 3 to 6 months with a temperature of 39°C or higher in at least the intermediate-risk group, and the NHS advises getting urgent medical advice. Have your baby seen soon.

Children over 6 months

For children over 6 months, NICE says the height of the temperature alone should not be used to judge how serious an illness is. Watch how your child behaves: smiling, responding normally, staying awake or waking easily, normal skin colour and a moist mouth are low-risk signs.

When to contact a doctor

Call a doctor or have your child seen soon if:

• The fever lasts more than 24 hours in a child under 2, or more than 3 days (72 hours) in a child aged 2 or older (AAP).
• The fever has lasted 5 days or more (NHS, NICE).
• There are other signs, such as a rash, a severe sore throat or earache, or repeated vomiting or diarrhoea (NHS, AAP).
• Your child does not want to eat, is not their usual self, or shows signs of dehydration (NHS).
• Your child still seems ill after the fever comes down, or seems to be getting worse (AAP).
• Your child has an immune system problem or is taking steroids (AAP).
• You are more worried than before, or feel you cannot look after your child (NICE).

Emergency signs: call 115

Call 115 or go to the nearest emergency department if your child has a fever and any of these signs (NHS, NICE, WHO):

• A seizure (fit).
• Very drowsy, hard to wake, or does not stay awake once woken.
• Cannot stop crying, is very agitated or confused, or has a weak, high-pitched cry.
• Difficulty breathing: grunting, very fast breathing, or the stomach sucking in under the ribs.
• Cannot drink or breastfeed, or vomits everything.
• A stiff neck, is bothered by light, or a bulging soft spot in a baby.
• A rash that does not fade when you press a glass against it.
• Pale, blue, grey or blotchy skin, or blue, grey or very pale lips or tongue.
• Unusually cold hands and feet.
• Not responding as they normally do, or no interest in feeding or usual activities.

If you suspect dengue

The WHO says the symptoms of severe dengue often come after the fever has gone away, so a falling temperature does not always mean recovery. Take your child to a health facility straight away if you notice severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, blood in vomit or stool, fatigue, restlessness, being very thirsty, pale and cold skin, or weakness. The WHO advises avoiding ibuprofen and aspirin, as they can increase the risk of bleeding. See also dengue warning signs.

Write down before the visit

1. The temperature, the time and how you measured it.
2. Any medicine given and when.
3. How much your child drank or fed, and the number of wet nappies.
4. Other symptoms and the date of the last vaccination.

Clinics can share this article with parents.

Sources

• High temperature (fever) in children — NHS
• Fever in under 5s: assessment and initial management (NG143) — NICE
• How to Take a Child's Temperature — American Academy of Pediatrics (HealthyChildren.org)
• Fever Without Fear: Information for Parents — American Academy of Pediatrics (HealthyChildren.org)
• Integrated Management of Childhood Illness: Chart booklet — WHO
• Dengue and severe dengue — WHO
• Reye's syndrome — NHS