Baby's fever: Do's and don'ts all parents must know

You know the signs, mums — hot, flushed little bodies, restlessness and over-bright eyes. Your little one’s temperature has risen and now, you are worried about your baby’s fever.

A baby’s fever is a cause for concern for mums around the world. This article provides you with information about this rather common occurrence in your little one, including how you can manage the fever at home without medication and when you should be worried.

What is fever?

A human body’s regular temperature is around 36-37C (98-100F). Normal body temperature varies from person to person. It may also be influenced by activities such as exercise, sleeping, eating and even the time of day. For example, your body temperature generally peaks at around 6pm and is at its lowest around 3am.

According to Dr Ratna Sridjaja of SBCC Baby and Child Clinic, Gleneagles Hospital Singapore, “fever occurs when the body’s internal ‘thermostat’ raises the body temperature above its normal level.”

She explains that this thermostat is located in the part of the brain known as the hypothalamus, which is responsible for regulating the body’s temperature and keeping it within the normal range.

When your little one is ill or has an infection, sometimes, the hypothalamus will increase the body’s temperature in response. Dr Sridjaja says that “researchers believe that turning up the heat is the body’s way of fighting the germs that cause infections and making the body less comfortable for them.”

So, when your child’s body temperature rises, it means his immune system is healthy and working hard to fight an infection or illness. And while it your baby’s fever certainly is a worry, do remember that a mild fever (around 37.5-37.7C) in a baby over the age of 6 months is usually no cause for concern and means that his immune system is working just fine.

Remember: fever itself is not an illness; it is a sign of illness/infection.

How to take your baby’s temperature

The medical experts at WebMD describe a few ways to take a baby’s temperature: rectally (via the rectum); orally (mouth); axillary (armpit); and forehead. You should only use a digital thermometer to take a child’s temperature as mercury thermometers carry the risk of mercury poisoning if they break.

The most accurate temperature reading for babies under the age of one year old can be obtained by using a rectal thermometer.

Here’s how you can take your baby’s rectal temperature using a digital thermometer, according to WebMD:

“First make sure the thermometer is clean. Wash it with soap and water or wipe it off with rubbing alcohol. Lay your baby on the belly or on the back with legs bent toward the chest.

“Apply a little bit of petroleum jelly around the thermometer bulb and gently insert it about 1 inch into the rectal opening. Hold the digital thermometer in place for about two minutes until you hear the ‘beep.’ Then gently remove the thermometer and read the temperature.”

Be sure to clearly label the rectal thermometer so it’s not subsequently used in your baby’s mouth. 

For children over the age of one year of age, paediatrician Dr. Cara Barone recommends using either an ear thermometer or an oral digital thermometer.

According to Dr Sridjaja, these are the temperatures that indicate a baby’s fever, depending on the type of thermometer you use:

• 38 C ( 100.4 F ) measured rectally ( in the bottom )
• 37.5 C ( 99.5 F ) measured orally ( in the mouth )
• 37 C ( 99 F ) measured an axillary position ( under the arm )

Common causes of fever

*The information in this section is adapted from Seattle Children’s Hospital.

Almost always, a fever is caused by an infection, with viruses causing 10 times more infections than bacteria.

The following are some of the most common causes of your baby’s fever:

• Viral Infections: Colds, the flu and other common viral infections are the most common causes of fever in babies. In fact, little ones — especially if they are in daycare — may have seven to 11 viral illnesses accompanied with fever per year. Often, fever might be the only symptom you notice in the first 24 hours, followed later by other symptoms such as a runny nose and/or cough.

• Bacterial Infections: These infections are the second most common causes of fever in babies. Look out for bladder infections in girls especially if she has no other symptom other than fever. Unexplained fever is also a symptom of common bacterial infections like strep throat.

• Sinus Infection: A sinus infection is a complication of a cold, with a symptom being the return of fever a few days after your child’s temperature returns to normal (along with sinus pain).

• Vaccine Fever: Many babies develop fever after most vaccines, usually within the first 12 hours. It may last for two to three. This is normal and harmless and means the vaccine is working. However, if your baby’s vaccine-related fever worries you, do see a doctor without delay.

• Overheating: Low grade fever can occur if your child is over-heated. This could be either via overdressing or high environmental temperature. His temperature will return to the normal range once he is moved to a cooler place or the unnecessary layers of clothing are removed. Rest and drinking extra fluids also help in re-establishing a normal temperature.

When to be worried about baby’s fever

Newborn fever

If your baby under the age of three months old develops a temperature over 38C (100.4F), you will need to show him to a doctor without delay, says Dr. Barone. It is also a cause for concern if your baby’s temperature drops to less than 35.5C (96F).

Worrying symptoms to look out for

Dr Sridjaja advises that you should see a doctor if your baby over three months of age has a fever under 39C, but also:

• refuses, or seems too sick to drink enough liquids
• has persistent vomiting and/or diarrhea
• shows signs of dehydration, such as being less alert/active than usual, crying without tears or urinating less than usual
• feels pain when urinating
• is suffering from a medical condition such as cancer, kidney or heart disease
• has fever for more than 72 hours
• also has a rash

Seek immediate medical attention, advises Dr Sridjaja, if your baby over three months of age has a fever over 39C, along with any of the following symptoms:

• Inconsolable crying and extreme irritability
• Lethargy and difficulty walking
• Rash or purple spots that look like bruises on the skin ( that were not there before the child got sick)
• Stiff neck
• Headache
• Blue lips, tongue or nails
• Seizure
• Infant’s soft spot on the head that bulges out or sunken inwards
• Difficulty breathing
• Learning forward and drooling

IMPORTANT INFORMATION: How to manage your baby’s fever – The Do’s and Don’ts

While fever is a sign of a healthy immune system, it’s still important to know ways of managing your child’s fever, because if it goes too high (over 40-41C) there may be a risk of your little one developing a febrile fit.

Here are some do’s and don’ts of managing your baby’s fever:

• Do give paracetamol or ibuprofen based on the package recommendations according to your baby’s weight and age. A syringe is the best way to ensure you are giving your little one the correct dosage. Avoid household teaspoons to measure out the medication, as you run the risk of overdosing or not giving enough of it.

• Do NOT give ibuprofen until you are sure your child’s fever is not caused by the dengue virus. This is because dengue affects the platelets, which are responsible for blood clotting, increasing the likelihood of internal bleeding. Ibuprofen (and aspirin too) has a similar blood-thinning effect, and can aggravate, instead of helping to control the condition.

• Do NOT give aspirin (unless advised by a doctor) due to its association with the potentially fatal Reye’s Syndrome.

• Do keep your child well hydrated as fever causes little ones to lose fluids faster. If he is under six months of age, breastfeed him more often. Your breastmilk also contains powerful antibodies that will help him fight the infection more efficiently.

• Do NOT give fever medications (i.e. panadol, ibuprofen) to a baby under two months of age says Dr. Sridjaja, unless advised to do so by a paediatrician.

• Do use a lukewarm compress to help bring your child’s fever down. Apply it under his armpits, on his forehead and on either side of his groin.

• Do NOT immerse your child in cold/icy water. Instead, fill your tub with just a few inches of tepid water and using a washcloth, dribble the water over your little one’s body to help bring his temperature down. Never leave your child unattended in the tub.

• Do NOT use rubbing alcohol as a way of lowering your child’s temperature.

• Do NOT over-medicate on fever medication. Read the label carefully for the recommended interval between dosages and stick to it.

• Do NOT “starve a fever”. Let your child eat what he likes, especially if he is already eating solids. This will give him much-needed energy to help him fight the infection. Don’t worry too much if he refuses solids, as long as he is drinking enough fluids and his urine output is normal.

• Do dress your child in light, cotton clothing and use a light blanket too. Overdressing and using too much bedding can raise his core temperature even more.

• Do encourage your child to rest. Running around can raise his temperature.

• Do not send your child to daycare or school while he has fever. Once your little one has been fever-free for 24 hours, he can go back.

Parents, if you are in doubt about what to do when it comes to your baby’s health — fever or otherwise — please consult your little one’s paediatrician without delay.

We hope you found this article helpful. Please share your thoughts on the topic of fever in baby’s by leaving a comment below.