Fever in Babies: What Are the Signs?

Babies cannot tell us what they need, so as parents or caregivers it is important to learn the signs of what the baby is experiencing and what they need. There are a few factors that will indicate if your infant has a fever. The first and most obvious sign of a fever is a tangible increase in temperature. Additionally there will also often be behavioral changes, which are important for you to notice as they could also indicate something other than a fever. A baby with a fever might differ from their normal sleeping pattern, either sleeping more or less. They could also be more fussy than usual. Another indication could be a change in their appetite. If you notice any of these signs it is worthwhile to check your baby’s temperature. It could be nothing but it is always good to be on the safe side! 

How Do I Take My Baby's Temperature?

There are a few different methods to take the temperature of an infant. Rectal readings are known to be most accurate for infants. The normal range of temperatures for an infant includes a reading of 98.6° F (37° C) as the average rectal temperature. A normal low temperature reading can be 96.8° F (36° C) in the morning. It can change to a high of 100.3° F (37.9° C) later in the day. Use a specific rectal thermometer and ensure to only insert the thermometer until the silver tip is covered. Depending on the thermometer, wait a few seconds until it beeps and then check the reading. The next most accurate thermometer for your baby is an IR device for use on the forehead or in the ear canal. These are generally more accurate than temperature strips. The eTherm IR digital thermometer, will give an almost instant reading of the infant’s temperature from either the forehead or ear canal. The eTherm was recently voted as the best thermometer for travel by CNN due in part to its slim design and durability. 

Generally the forehead temperature is slightly higher than the rectal temperature, so there is no need to worry if the temperature is slightly higher than the above mentioned normal. However it is still a highly recommended tool often used in doctor’s offices. Ear thermometers are also a common selection however this is not accurate for baby’s under 6 months. The armpit thermometer is also less reliable however it is simple to use for all ages. 

What is too high for a baby's fever?

It is important to maintain perspective. These ranges will help give context to the type of fever:

100° - 102° F (37.8° - 39° C) Low grade fever: Don't treat.

102° - 104° F (39 - 40° C) Average fever: Treat if it causes discomfort.

Over 104° F (40° C) High fever: Always treat.

Over 106° F (41.1° C) Very high fever: Important to bring it down. Rare to go this high.

Over 108° F (42.3° C) Dangerous fever: Fever itself can be harmful.

What Causes Infant Fevers?

There are many situations which might cause a fever. For the most part a fever should not cause too much panic. It signals that the baby’s body is fighting an infection. 

There are a few potential causes of a fever in infants; viral infections are the most common cause - this includes colds, flue and roseola. With a viral infection often fever will be the first symptom that presents itself. Usually the remaining symptoms will begin to present themselves within 24 hours of the fever, so depending on the severity of the fever it is recommended to wait for the other symptoms so you can treat the infection rather than merely the symptom. Bacterial infections can also occasionally be the root of a fever. 

Young infants also receive many vaccines to help them fight illnesses present in the world. It is normal for a baby to exhibit signs of a fever within the first 12 hours, which can last for up to 3 days. However this should not be a cause for concern, while the fever should be monitored, it is a good indication of the infant’s immune system learning how to combat disease. 

Overheating can also raise the temperature of an illness. At such a young age, the body is not yet efficient at controlling their body temperature. It is important to dress your infant appropriate to the weather that they are going to encounter. When they have a raised temperature caused by overheating it is recommended to dress the baby in single layer lightweight clothing. Conversely when going into a cold environment it is vital to make sure that their body temperature can be maintained by dressing them warmly. 

When should you worry about a baby's fever?

There are two cases in which an infant fever is concerning. The first is if the fever happens within the first 3 months of the baby’s life. This is known as Newborn Fever and should be taken seriously. It could indicate sepsis - a blood infection or a bacterial infection. The infant’s immune system at this point is still very vulnerable so any infection in this age group should be treated immediately so as to prevent the infection from overworking the body. 

The second worrying cause of a fever is Meningitis. This is dangerous at all ages, it is a bacterial infection of the membrane that covers the spinal cord and brain. A stiff neck, headache and confusion are the common symptoms. In younger children and babies it is expressed as lethargy or irritability to the point that they can't be consoled. If Meningitis is not treated early, it can cause brain damage.

What should I do if my baby has a fever?

If your child is suffering from a fever the first course of action is to consult your pediatrician. But don’t worry! There are a few things you can do to help. The first thing you can do is ensure your baby is hydrated, having enough cool liquids in their system will help regulate the body temperature of your infant. Another common technique is to give your baby a sponge bath. This will help soothe while also bringing down the temperature naturally. It is important to use lukewarm water as cold water could cause the baby to shiver in turn escalating the fever.

Keeping your baby safe is your first priority, so remain vigilant. Checking your baby’s temperature can give you peace of mind, knowing that your infant is healthy. If your baby does develop a fever, remember that it is their body learning how to fight the different germs and bacteria in their surroundings and this will help them be strong and healthy in the future. Check with a doctor to ensure the best care for your child and trust your instincts.