Baby Fever: What’s normal, how to treat a fever, and when to see a doctor

Updated on 15 June 2024.

Dr Golly’s guide to managing your child’s fever.

The first time that your baby gets sick with a temperature can be just as upsetting for you as it is for your baby.

In this blog I’ll walk you through fevers – what is considered normal, when to be concerned and how you can lower their temperature and keep them comfortable.

Q 1: What is considered the normal temperature range for a baby?

A: The normal temperature for a baby is between 36°C and 37.5°C degrees, although this can vary according to the time it is taken, the method of checking and the device used.

Q2: What is considered a high temperature for a baby?

A: Fever – often referred to by us as a ‘febrile episode’ is defined as a body temperature above the normal range, which is typically considered to be 38°C or 100.4°F. However, it’s important to note that normal body temperature can vary slightly from child to child, at different ages, and even throughout the day. There is a general push to move away from measuring the exact number as there is so much variance in thermometers.  The trend (e.g. a consistently rising temperature), environment and other symptoms is what we’re looking for. 

A baby’s history, signs and symptoms will often dictate whether a high temperature is of concern, for example, they may have a high temperature because of excess clothing, wraps or blankets. 

For newborns under 3 months  anything over 37.5°C should be reviewed immediately, sometimes just temperature instability can be a sign of infection.

Q3: What is the best way to take a baby’s temperature?

A: The most accurate measurement of body temperature is with a rectal thermometer, this can be uncomfortable for bub and potentially dangerous to use; I don’t recommend these. For parents, the least distressing are the digital thermometers that are placed in the ear, rubbed across the forehead, or modern ones that use infrared technology and can be taken from a distance.

Q4: What can be some of the common reasons for a raised temperature in a baby?

A: The most common cause for a short-lived, mild fever is a viral infection, and the slight jump in temperature is a good sign that your child’s immune system is fighting strong. It’s important to note that fever is not an illness, but rather a symptom of the presence of an illness or inflammation. Therefore, it’s important to not only treat the illness symptoms but also the underlying cause, if known.

Common causes of fever include:

• Mild chest colds, ear and throat infections  should be of less concern if they are occurring infrequently – up to once per month – and lasting no longer than 48 hours in duration.
• While teething can also be a very common cause of raised temperatures in babies and can occur as early as a few months of age, it’s unusual for this to cause a temperature over 38°C.
• Other causes of raised temperature are chronic disease or overheating caused by sunburn or heat stroke.
• Serious causes of fever include bacterial infection, for example of the urine, lungs (pneumonia), blood or brain (meningitis).

Q5: Are there signs – other than taking a child’s temperature – that can indicate a raised temperature?  How to tell if a baby has a fever without a thermometer?

A: Having a raised temperature can cause children to be uncomfortable and irritable, and they may complain of feeling cold when they are hot to touch

Other common signs of fever in children include:

• Your child’s forehead may be hot to touch  
• Warm or flushed skin and cheeks
• painful muscles 
• Sweating
• Chills or shivering
• Irritability or fussiness
• Decreased appetite or fussy at the breast or bottle 
• Lethargy or sleepiness

Q6: At what temperature is there cause for concern and what should a parent do?

A: The degree of a fever or raise body temperature isn’t necessarily related to the severity of the underlying cause. 

Parents should be more concerned if their child show signs of: neck stiffness or is bothered by light in their eyes, as these are possible signs of meningitis – get to your nearest hospital emergency department immediately.

What to do when a baby has a fever? 

A fever in a baby under three months should always be reviewed by a doctor to determine the cause even if they have no other symptoms.

When Fever is a Concern – When should you worry about baby and child fevers?

While fever is generally a normal response to illness, there are certain situations where you should seek medical attention:

• Infants under 3 months old: Any newborn fever warrants immediate medical evaluation.
• High fever: A fever above 38.5°C (101.3°F) may need to be evaluated, especially if accompanied by other symptoms.
• Persistent fever: A fever lasting more than 3-5 days, regardless of the temperature, should be checked by a doctor.
• Concerning symptoms: If your child has a fever along with any trouble breathing, a stiff neck, severe headache, rash, confusion, or other worrying signs, seek medical attention promptly.

Should the above symptoms appear in your baby, or if you are simply worried that the fever may represent something more serious, I always recommend going to a doctor.

Q7: What are the ways in which a parent can reduce their child’s fever ?

A: In good news children handle fever quite well and most cases, mild fevers can be managed at home with supportive care:

• Hydration: Encourage your child to drink plenty of fluids – and oral rehydration solution is best but water, formula, (or even diluted juice at a pinch – any fluid is better than no fluid). For breastfed babies or breastfed child continue to breastfeed and offer the breast more often. For a formula fed child continue to feed but you can switch to an oral rehydration solution for a short period if needed. This helps prevent dehydration, which can make them feel worse.
• Comfort measures: Dress your child in light clothing and keep the room at a comfortable temperature. You can also give them a lukewarm bath or sponge bath to help cool them down. Remember though – reducing the temperature will not help your child fight an infection – it will only make them more comfortable. If they are complaining of being cold don’t try and cool them down.
• Fever-reducing medications: Over-the-counter pain relief medication like paracetamol or ibuprofen can help reduce fever and relieve discomfort. Always follow the recommended dosage for your child’s age and weight, and consult your doctor or pharmacist if you have any questions.

How to relieve a fever in babies?

Remember for any fever in a baby under 3 months you are going to have them reviewed immediately – your doctor will talk you through what to do next. 

DISCLAIMER: As always, this advice is general in nature and if you are worried in any way about your baby’s health or child’s fever always consult your child’s doctor.