Baby Fever: Is It Normal? What You Should Do About It

When your baby's forehead feels warm to the touch, it's natural to worry. Is it just a mild infection, or could it be something more serious? The uncertainty can feel especially daunting, particularly if this is your first time dealing with a fever in such a young child.

A fever happens when your baby's body is fighting off an infection or illness. While most fevers in babies are caused by common infections and settle on their own, some signal conditions that need medical attention. Knowing the difference between "monitor at home" and "go to hospital now" helps you act quickly when it matters and feel calm when it doesn't.

What temperature is too high for a baby?

A normal temperature for babies ranges from 36.5°C to 37.5°C. Anything above 38°C is considered a fever.

For babies under three months, any fever of 38°C or higher needs immediate medical attention. Their immune systems are still immature, and infections can develop quickly.

For babies aged three to six months, contact your doctor if the fever reaches 39°C or higher.

For babies over six months, how they're acting matters more than the exact number on the thermometer. A baby with a 39°C fever who's still playing and drinking is often less worrying than one with 38.5°C who seems really unwell. 

When deciding whether to contact your doctor, consider both the temperature reading and how your baby is behaving. 

How do you know if your baby's fever is serious?

Deciding whether to rush to hospital or monitor at home can feel worrying when your baby is unwell, especially in the middle of the night. Knowing which signs to watch for can help you feel more confident when it matters most.

Go to your doctor immediately if your baby shows any of these signs:

• Under three months old with any fever

• Difficulty breathing or breathing very fast

• Blue, pale, or ashen skin

• Unusually floppy or drowsy

• Having a febrile seizure

• A rash that doesn't fade

• Hasn't had a wet nappy for 12 hours

• Vomiting persistently and unable to keep fluids down

Most fevers won't involve these symptoms, but if something doesn't feel right, trust your instincts – getting checked and reassured is always better than waiting at home and worrying.

How to take your baby's temperature

Taking an accurate temperature is straightforward once you know the right technique. For babies, an armpit reading with a digital thermometer is the reliable and comfortable method.

Follow these steps for a reliable reading:

1. Place the thermometer snugly in your baby's armpit

2. Hold their arm gently against their body

3. Wait for the beep, usually about a minute

4. Add 0.5°C to the reading to get the true body temperature

5. Clean the thermometer with cool soapy water after each use

Armpit readings run about 0.5°C cooler than core body temperature because the armpit is further from your baby's internal organs. Adding 0.5°C adjusts for this difference and gives you the accurate number for those crucial age-based thresholds, like 38°C for babies under three months.

How to help your baby feel comfortable with a fever

Your care can make all the difference when your little one has a fever. Here's how you can help them feel more comfortable while their body fights infection.

Keep them cool (not cold)

When your baby has a fever, simple steps can help them feel more at ease without overcooling them.

You can help by:

• Dressing them in light, breathable clothing. One layer is enough because heavy clothes trap heat and make it harder for a fever to come down.

• Keeping the room between 18°C and 20°C

• Gently wiping their face, neck, arms, and legs with a soft cloth

Never use cold water or ice to cool your baby. When your baby shivers, their body interprets cold as a threat and generates heat. This actually raises the temperature, which is the opposite of what you're trying to achieve.

Offer plenty of fluids

Keeping your baby hydrated is one of the most important things you can do. When they have a fever, their body loses more water than usual through sweating and faster breathing.

Staying hydrated helps them fight infection while preventing dehydration, which can make your baby feel even worse.

You can help by:

• Breastfeeding more frequently if you're nursing

• Offering small amounts of cooled boiled water for older babies (over 6 months)

• Offering diluted juice for toddlers over 12 months if they prefer it

If you notice fewer wet nappies than usual, your baby may need more fluids. Checking for wet nappies every few hours tells you whether they're getting enough.

When to give fever medicine

Working out the right dose of medicine for your baby can feel overwhelming when you're already worried – and it's worth knowing that you don't always need to give it.

Fever is the body’s natural way of fighting infection, raising your baby’s temperature to make it harder for bacteria and viruses to thrive and support the immune system.

You can give paracetamol or ibuprofen to help your baby feel more comfortable if they seem distressed.

If you do give medicine:

• Always check the packaging for the correct dose based on your baby's age and weight

• Paracetamol is suitable from two months old

• Ibuprofen can be given from three months (if your baby weighs over 5 kg)

• Don't give both medications together unless your doctor advises this

Your pharmacist and doctors help you calculate the exact dose if you're unsure, and it's always better to check than to guess.

Don't wake a sleeping baby to give fever medicine. Sleep allows your baby's body to direct all its energy toward fighting infection, bringing the temperature down. If your baby is playing, feeding, and seems content despite the temperature, they may not need medicine.

What causes fever in babies?

Recognising what might be causing the fever can help you feel more in control. Your baby's other symptoms often give clues about what's causing the fever.

Viral infections

Viral infections are the most common cause of fever in babies. Your baby's body fights these off without medication in most cases.

Alongside the fever, you might notice:

• A runny nose or cough

• A sore throat

• Fussiness or general irritability

• Restlessness or difficulty settling

These symptoms usually improve within a week. The fever typically peaks in the first two to three days, then gradually settles as your baby’s immune system gains control. Your comfort and care during this time make a real difference.

Ear infections

Ear infections often follow colds and may need antibiotic treatment. 

Signs to watch for:

• Your baby pulling at their ear

• Trouble sleeping or increased fussiness

• Fever alongside ear discomfort

If you suspect an ear infection, book an appointment with your doctor. They can examine your baby's ears and recommend the right treatment.

Urinary tract infections

Urinary tract infections can occur without obvious symptoms, which is why doctors sometimes check urine when a baby has a fever with no clear cause.

You might notice:

• Fever without cold symptoms

• Unusual fussiness or crying

• Strong-smelling urine

Your doctor can test a urine sample to check for infection. If confirmed, antibiotics usually clear it up quickly.

Vaccination reactions

A mild fever after vaccinations is normal and a reassuring sign that the vaccine is working.

What to expect:

• Mild fever within 24 to 48 hours of immunisation

• Fever that settles within a day or two

• Your baby may benefit from paracetamol if they seem uncomfortable

This mild reaction means your baby's immune system is learning to recognise and fight the disease. They're building protection without the risks of actual infection. 

Most fevers in healthy babies resolve within three to five days, and the vast majority never develop serious complications. If you feel worried or uncertain at any point, don't hesitate to contact your doctor. You know your baby best, and getting checked is always a reasonable choice.

If you’re unsure what’s causing your baby’s fever or just want reassurance, request an appointment at Thomson Medical. Our doctors can examine your baby, identify the likely cause, and guide you on the right care and monitoring at home.

FAQ

Do high fevers cause seizures?

Does teething cause fevers?

Teething may cause a slight rise in body temperature, but rarely above 38°C. If your baby has a proper fever, don't assume it's just teething. Viral infections and bacterial infections are far more common causes of fever in children.

How high is too high for a fever?

For babies under three months, any fever of 38°C or higher needs emergency room attention immediately. For babies three to six months old, seek urgent help if the fever reaches 39°C or above.

Can I use paracetamol for a 2-month-old baby?

Yes, paracetamol can be given to babies from two months old. Always check the packaging for the correct dose based on your baby's weight and age. However, any baby under three months with a fever needs medical assessment before giving fever medications. Contact your doctor for advice first.

My baby has a fever but seems happy and playful – is that normal?

Should I use cold water or ice to bring down my baby's fever?

Never use cold water, ice, or cool compress methods to reduce fever. Cold temperatures cause shivering, which actually raises body temperature further and makes your baby uncomfortable. If you want to help cool your baby, tepid sponging with lukewarm tap water is safe.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice based on your little one's situations, request an appointment with Thomson Medical today.