Natick Pediatrics, PC

Fever Demystified

Robert P. Lindeman, MD, PhD
Natick Pediatrics, PC
Fever in children generates a lot of worry in parents and is one of the most common reasons why parents call the pediatrician. Fortunately, the more parents know about fever, the less worrisome it becomes.

Fever is your friend
Fever is often described as the body "turning up the thermostat" so that it can fight off infection. Most experts believe that our immune system is better able to fight infections in a hotter environment.

A fever is defined as a body temperature above 100.4 degrees F in an infant less than 2 months old, or above 101° F in an older child. Many things may cause a child’s temperature to rise, but the most common cause is a viral infection. Viruses cause fevers just high as bacterial infections do. A high fever does not mean your child needs antibiotics. A fever will always come back down on its own, even if you do not give medicine.

In fact, the height of the fever indicates little about how sick the child is. The most important things to consider are how the child looks and behaves, and how well the child is drinking. For instance, I wouldn’t worry very much about a five-year old with a temperature of 103° F who is busy building with Lego or playing computer games. I also worry a lot less about an infant with a fever who continues to drink and make wet diapers.

But just as the presence of fever does not necessarily mean a child is very ill, the absence of fever does not guarantee that a child is healthy. If a child has no fever, but is staring into space and is slow to respond to his parents, this is cause for concern and you should call the doctor. Or if a sleeping child will not wake unless he is being jostled, and then falls asleep again when you stop jostling, the body temperature is unimportant: call your child’s doctor! Say an infant usually nurses every 3 hours but refuses the nipple and goes back to sleep. If three hours later the baby still doesn’t want to nurse, I don’t care what the baby’s temperature is: You should call the doctor!

Seizures with fever
Though all children get fevers, only 4% of children have seizures (convulsions) with fever. Seizures with fever occur most often in children between the ages of 18 months and 6 years. With these children, what causes the seizure is not the height of the fever but the speed with which the fever rises. Most of the time, these children have a seizure before the parents even know that the child is sick. These seizures -- though terrifying to witness -- are usually short and do not damage a child’s brain. A high fever will not "cook" a child’s brain, as some people mistakenly believe. Fever does not damage the brain unless the temperature rises above 107 degrees F, which is extremely rare.

Taking a child’s temperature
Most parents take too many temperatures. But it’s part of our human nature to seek out numbers to help us make decisions. In the case of body temperature, however, the number can lead us to make decisions that are not always in the child’s best interest, such as going to the emergency room. I recommend taking the temperature of a child only if the child is less than 6 months old, unless the child is not fully-immunized; or if the child is older and has cancer, AIDS, or certain other chronic diseases. I never recommend taking the temperature of a child who does not feel hot. There is very little chance that a thermometer is going to detect something that your hands cannot. Many parents prefer the "kiss test," since the contrast between a parent’s cold hand and a child’s forehead may create a false sense of warmth.

For children younger than 6 months of age, I recommend taking a rectal temperature. Today’s digital thermometers are relatively fast – some give a reading in under 10 seconds. Using a small amount of water-based lubricant (K-Y or the equivalent), you insert the probe half an inch and very quickly you will have an accurate temperature reading. Nothing bad will happen to your baby if you do this. Rectal temperatures are far more accurate and reliable than axillary (armpit) temperatures. Also, you should avoid using temperature-sensitive skin strips or "pacifier" thermometers, which may be convenient, but are highly unreliable and not at all accurate.

After a child reaches 6 months of age, I recommend that parents take the thermometer outside. Place the thermometer on the ground in the driveway or the street. Then, take the heaviest vehicle you own (preferably an SUV) and drive back and forth over the thermometer. This method helps parents reduce the temptation to take their children’s temperatures.

Caring for a child with fever
The two most important treatments for a sick child with fever are fluids and sleep. Any medication you might give (e.g. ibuprofen/Advil or acetaminophen/Tylenol) is only useful if it helps the child do these two things. The better hydrated a child is, the cooler he or she will be. The more the child is allowed to sleep, the better he or she will feel when awake. So the opposite is also true: a dry sleepless child will be hotter and feel crummier. You should not take the temperature of a sleeping child (you might awaken the child), and you certainly should not awaken a child to give him/her fever medicine!

Fluids: Encourage, but do not force, your child to drink extra fluids. Ice pops count!

Dress: Keep your child dressed in cool clothing: one layer if room temperature permits. If the child is shivering, use a light blanket.

Sponging: You should avoid giving sponge baths in general and you should never sponge bathe a child with rubbing alcohol (methanol). This is very dangerous because methanol is toxic and is absorbed through the skin. If you must sponge bathe a child with a fever, give acetaminophen (Tylenol) first and wait at least 1/2 an hour.

Fever/comfort medicines: These medicines only lower the body's temperature 2-3 degrees F, and so will not return your child's temperature to normal unless it was not high to begin with. You can expect to give repeated doses over the course of an illness because fevers go up and down frequently until the illness is over.

Acetaminophen (Tylenol) may be given every 4 hours, but no more than 5 times per day. Ibuprofen (Motrin/Advil) may be given every 6 hours. Do not give ibuprofen to a child younger than 6 months old. You should never give aspirin to a child. Aspirin causes a rare but fatal reaction in some children known as Reye Syndrome.

Make sure you are giving the correct amount of medicine. Acetaminophen and ibuprofen, like all pediatric medicines, are dosed according to a child’s weight, not the child’s age. Dosing information on medicine packaging is not always accurate. Since the dose increases as the child grows, I always try to remind parents at well-visits of the child’s current medicine dose.

Rest: Sleep is extremely important in recovery from any illness, particularly febrile illnesses. If the child will not or cannot sleep, I recommend quiet restful activities (in these cases, I sometimes even recommend television!). Acetaminophen and ibuprofen help many children get the rest they need to speed their recovery.

When to call the doctor

Call the doctor immediately if:

Your child is less than 2 months old and the temperature is 100.4 degrees F or greater.
Your child cries non-stop for 1 hour
Your child is difficult to wake up
Your child's neck is stiff
There are purple spots on your child's skin
Your child cannot swallow and is drooling
Your child looks and acts very sick (if possible, give fever medicine and check the child again in 1 hour)

Call the doctor during regular hours if:

The fever lasts more than 72 hours
Your child tells you he/she has an ear ache, sore throat, or painful urination
Temperature is more than 104 degrees F and the child is less than 2 years old
Your child has a history of seizures with fever

For more information about Natick Pediatrics, or to talk to the doctor, please call the office at (508) 655-9699.

Medical Office Building
MetroWest Medical Center
Leonard Morse Campus
67 Union Street, Suite 305
South Natick, MA 01760

(508) 655-9699
(508) 655-2984 fax

Posted: April 14, 2003

Fever Demystified

Robert P. Lindeman, MD, PhD
Natick Pediatrics, PC

Fever in children generates a lot of worry in parents and is one of the most common reasons why parents call the pediatrician. Fortunately, the more parents know about fever, the less worrisome it becomes.

Fever is your friend
Fever is often described as the body "turning up the thermostat" so that it can fight off infection. Most experts believe that our immune system is better able to fight infections in a hotter environment.

A fever is defined as a body temperature above 100.4 degrees F in an infant less than 2 months old, or above 101° F in an older child. Many things may cause a child’s temperature to rise, but the most common cause is a viral infection. Viruses cause fevers just high as bacterial infections do. A high fever does not mean your child needs antibiotics. A fever will always come back down on its own, even if you do not give medicine.

In fact, the height of the fever indicates little about how sick the child is. The most important things to consider are how the child looks and behaves, and how well the child is drinking. For instance, I wouldn’t worry very much about a five-year old with a temperature of 103° F who is busy building with Lego or playing computer games. I also worry a lot less about an infant with a fever who continues to drink and make wet diapers.

But just as the presence of fever does not necessarily mean a child is very ill, the absence of fever does not guarantee that a child is healthy. If a child has no fever, but is staring into space and is slow to respond to his parents, this is cause for concern and you should call the doctor. Or if a sleeping child will not wake unless he is being jostled, and then falls asleep again when you stop jostling, the body temperature is unimportant: call your child’s doctor! Say an infant usually nurses every 3 hours but refuses the nipple and goes back to sleep. If three hours later the baby still doesn’t want to nurse, I don’t care what the baby’s temperature is: You should call the doctor!

Seizures with fever
Though all children get fevers, only 4% of children have seizures (convulsions) with fever. Seizures with fever occur most often in children between the ages of 18 months and 6 years. With these children, what causes the seizure is not the height of the fever but the speed with which the fever rises. Most of the time, these children have a seizure before the parents even know that the child is sick. These seizures -- though terrifying to witness -- are usually short and do not damage a child’s brain. A high fever will not "cook" a child’s brain, as some people mistakenly believe. Fever does not damage the brain unless the temperature rises above 107 degrees F, which is extremely rare.

Taking a child’s temperature
Most parents take too many temperatures. But it’s part of our human nature to seek out numbers to help us make decisions. In the case of body temperature, however, the number can lead us to make decisions that are not always in the child’s best interest, such as going to the emergency room. I recommend taking the temperature of a child only if the child is less than 6 months old, unless the child is not fully-immunized; or if the child is older and has cancer, AIDS, or certain other chronic diseases. I never recommend taking the temperature of a child who does not feel hot. There is very little chance that a thermometer is going to detect something that your hands cannot. Many parents prefer the "kiss test," since the contrast between a parent’s cold hand and a child’s forehead may create a false sense of warmth.

For children younger than 6 months of age, I recommend taking a rectal temperature. Today’s digital thermometers are relatively fast – some give a reading in under 10 seconds. Using a small amount of water-based lubricant (K-Y or the equivalent), you insert the probe half an inch and very quickly you will have an accurate temperature reading. Nothing bad will happen to your baby if you do this. Rectal temperatures are far more accurate and reliable than axillary (armpit) temperatures. Also, you should avoid using temperature-sensitive skin strips or "pacifier" thermometers, which may be convenient, but are highly unreliable and not at all accurate.

After a child reaches 6 months of age, I recommend that parents take the thermometer outside. Place the thermometer on the ground in the driveway or the street. Then, take the heaviest vehicle you own (preferably an SUV) and drive back and forth over the thermometer. This method helps parents reduce the temptation to take their children’s temperatures.

Caring for a child with fever
The two most important treatments for a sick child with fever are fluids and sleep. Any medication you might give (e.g. ibuprofen/Advil or acetaminophen/Tylenol) is only useful if it helps the child do these two things. The better hydrated a child is, the cooler he or she will be. The more the child is allowed to sleep, the better he or she will feel when awake. So the opposite is also true: a dry sleepless child will be hotter and feel crummier. You should not take the temperature of a sleeping child (you might awaken the child), and you certainly should not awaken a child to give him/her fever medicine!

Fluids: Encourage, but do not force, your child to drink extra fluids. Ice pops count!

Dress: Keep your child dressed in cool clothing: one layer if room temperature permits. If the child is shivering, use a light blanket.

Sponging: You should avoid giving sponge baths in general and you should never sponge bathe a child with rubbing alcohol (methanol). This is very dangerous because methanol is toxic and is absorbed through the skin. If you must sponge bathe a child with a fever, give acetaminophen (Tylenol) first and wait at least 1/2 an hour.

Fever/comfort medicines: These medicines only lower the body's temperature 2-3 degrees F, and so will not return your child's temperature to normal unless it was not high to begin with. You can expect to give repeated doses over the course of an illness because fevers go up and down frequently until the illness is over.

Acetaminophen (Tylenol) may be given every 4 hours, but no more than 5 times per day. Ibuprofen (Motrin/Advil) may be given every 6 hours. Do not give ibuprofen to a child younger than 6 months old. You should never give aspirin to a child. Aspirin causes a rare but fatal reaction in some children known as Reye Syndrome.

Make sure you are giving the correct amount of medicine. Acetaminophen and ibuprofen, like all pediatric medicines, are dosed according to a child’s weight, not the child’s age. Dosing information on medicine packaging is not always accurate. Since the dose increases as the child grows, I always try to remind parents at well-visits of the child’s current medicine dose.

Rest: Sleep is extremely important in recovery from any illness, particularly febrile illnesses. If the child will not or cannot sleep, I recommend quiet restful activities (in these cases, I sometimes even recommend television!). Acetaminophen and ibuprofen help many children get the rest they need to speed their recovery.

When to call the doctor

Call the doctor immediately if:

Your child is less than 2 months old and the temperature is 100.4 degrees F or greater.
Your child cries non-stop for 1 hour
Your child is difficult to wake up
Your child's neck is stiff
There are purple spots on your child's skin
Your child cannot swallow and is drooling
Your child looks and acts very sick (if possible, give fever medicine and check the child again in 1 hour)

Call the doctor during regular hours if:

The fever lasts more than 72 hours
Your child tells you he/she has an ear ache, sore throat, or painful urination
Temperature is more than 104 degrees F and the child is less than 2 years old
Your child has a history of seizures with fever

For more information about Natick Pediatrics, or to talk to the doctor, please call the office at (508) 655-9699.

Natick Pediatrics, PC
Medical Office Building
MetroWest Medical Center
Leonard Morse Campus
67 Union Street, Suite 305
South Natick, MA 01760

(508) 655-9699
(508) 655-2984 fax

Posted: April 14, 2003