Fever in children: When should you worry?

When your child has a fever, it can be extremely distressing – for you both. But while having a fever can make your child feel pretty miserable and uncomfortable, it’s a completely normal response to an infection in the body. In fact, a high temperature can even help the body’s immune system fight off the illness.

Signs of fever in kids and babies are similar to adults: they might have a flushed and red face, or it may be hot to the touch; they could be sweating, shivering or have chattering teeth; and may be not feeling great overall. If you suspect your child may have a fever, you can use a thermometer to take their temperature.

A normal baby or toddler temperature range is 36.5°C to 38°C – anything above 38°C is considered a fever. For adults, this shifts to around 36-37°C. But while fever in children can be frightening, especially for first-time parents, a high kids’ temperature alone isn’t necessarily cause for alarm.

“If your child is more than three months old, it’s not the number on the thermometer that actually concerns us,” says paediatric doctor Nelu Simonsz. “You could come in with a fever of 42°C and that, in itself, isn’t a concern. Then again, you can have a fever of 38°C degrees and be really sick. What’s more important is what is causing the temperature.”

It is important to note, however, that a high temp in babies less than three months of age should be attended to straight away, even with no other symptoms present. Take your little one straight to the nearest emergency department.

The most common cause of a fever, says Nelu, is infection – so with children having an average of up to 10 infections a year, it’s not surprising that fever is common in kids. The most common infections are viruses, like a cold or flu, adds Nelu.

“Unfortunately, that’s the one thing we can’t treat, but it’s far and away the most common thing that causes fevers in kids,” she explains. “Then there are bacterial infections and things like inflammation, which could also cause kids’ temperatures to rise.”

So what should you do if your child’s temperature is sitting above the normal range for a toddler or baby? As above, for children under three months, urgent medical review is recommended, and that is especially the case for children in their first month of life. For older children you can initially offer at-home treatment to keep them comfortable (keeping in mind that treating the fever won’t fix the underlying cause, such as an infection).

“Pain relief and fluids are the most important things that you can do at home. Paracetamol, ibuprofen and cuddles – everything that you can think of to settle them,” suggests Nelu, who stresses that keeping kids hydrated is key. “Give them small frequent feeds. A baby might not take their 200ml bottle, but that’s okay – just give them 50ml more often. For older kids, offer their sippy cup to them every five minutes.”

They may also like to eat foods that contain a lot of fluid, like jelly and icy poles, and fruit such as grapes and watermelon, Nelu suggests.

Children’s paracetamol and/or ibuprofen can also help ease other potential symptoms of the underlying infection, such as a sore throat.

“When parents bring feverish babies to the hospital, paracetamol is usually the first thing we give them,” says Nelu. “We watch them, and if they perk up a bit, enough to have a drink and seem more comfortable, then that’s a really good sign that you can probably keep on top of it at home.”

Other at-home measures to make your child more comfortable include wiping their forehead with a lukewarm face washer, but avoid giving them cold baths or showers, which can make them shiver and increase their temperature. Dress them in light clothes to keep them cool and if they’re shivering, add more clothes or a blanket.

Related: Paracetamol vs ibuprofen: Is there a difference?

If you have a gut feeling that something’s wrong, or you just feel like your child’s not right, always see a healthcare professional

Most illnesses causing a fever can be managed at home for the first few days if the parents are confident about what’s causing the fever and can manage the symptoms, Nelu says. For other instances, a GP is a good first port of call. There are a few signs that you should seek medical attention, she adds, including dehydration.

“If they’re having less than half their normal fluids, or they’ve had around half their usual number of wet nappies, that could be an indication of dehydration,” Nelu says. “Keeping an eye on fluid going in and coming out is a really good way for parents to keep track of how things are going.”

Lethargy can also be concerning, particularly if you’ve given paracetamol and seen no change. “If they’re not waking up for feeds, if you wake them up and they fall asleep straight away, if they’re not having any periods of being awake and active and moving around – that can be a concern.”

Another warning sign is a rash that doesn’t disappear when you press down on it.

“It is still most likely a virus, but it can be a nasty bacterial infection, so that’s the sort of rash you’d get seen to straight away, especially if it’s spreading quickly,” shares Nelu, who adds that fever without a clear reason for more than 48 hours should also get checked.

“That also goes for fever where there is a known cause – for example, viral tonsillitis – but which still lasts for two days, because occasionally kids can pick up a secondary bacterial infection.”

If your child has a fever and is also twitching, convulsing or in pain, having trouble breathing or crying constantly without being settled, seek medical advice.

Nelu’s advice is simply to always get your child checked if you’re worried. “If you have a gut feeling that something’s wrong or you just feel like your child’s not right, always see a healthcare professional.”

When you think your child might need medical assistance, you have a few options. You can book an appointment to see your family GP, go to the emergency room of your closest hospital. If you're unsure, use nib's Symptom Checker to get guidance on when to seek medical attention based on the seriousness of your child's symptoms.

Related: I have a health concern, what do I do?

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Please note: The tips throughout this article serve as broad information and should not replace any advice you have been given by your medical practitioner.

Dr Nelu Simonsz is a paediatric doctor with a passion for educating parents on common health issues that affect kids. She believes that misinformation leads to unnecessary concern that can make parenting harder than it already is – but by sharing credible information in a relatable way, she’s committed to empowering parents. Outside work, Nelu is also passionate about Beyoncé – in fact, she’s so committed to the pop queen she once camped out at the airport to snap a pic with her!