Fever is the body's
normal and healthy reaction to infection and other illnesses, both minor and
serious. Fevers help the body fight infection. Fever is a symptom, not a
disease. In most cases, fever means your child has a minor illness. Often you
must look at your child's other symptoms to determine how serious the illness
is. Although it may be scary when your child's temperature goes up, fever is
The average normal body
temperature is about
37°C (98.6°F). It usually rises
during the day from a low of
36.5°C (97.7°F) in the morning
to a high of 37.5°C (99.5°F) in the late afternoon. Each child has a normal temperature
range that may be different from another child's. Mild increases to
38°C (100.4°F) can be caused by exercising,
wearing too many clothes, taking a hot bath, or being outside in hot
Temperature varies depending on how you take it. The most common methods to measure it are:
To convert a temperature from one method to another, use the Interactive Tool: How Do Temperatures Compare?
You can also use:
Some methods may not be as reliable or accurate as others. For information about taking
accurate temperatures, see the topic
If you think your child
has a fever but you are not able to measure his or her temperature, it is
important to look for other symptoms of illness.
Children tend to
run higher fevers than adults. The degree of fever may not indicate how serious
your child's illness is. With a minor illness, such as a cold, a child may have
a temperature of 40°C (104°F), while a very serious infection may not
cause a fever or may cause only a mild fever. With many illnesses, a fever temperature can go up and down very quickly and often, so be sure to look for other
symptoms along with the fever.
Babies with a fever often have an infection caused by a virus, such as a cold or the flu. Infections caused by bacteria, such as a urinary infection or bacterial pneumonia, also can cause a fever. Babies younger than 3 months should be seen by a doctor anytime they have a fever because they can get extremely sick quickly.
A fever in a healthy child is
usually not dangerous, especially if the child does not have other symptoms and
the fever goes away in 3 to 4 days. Most children who have a fever will be
fussy and play less and may not eat as much as usual.
may make your child uncomfortable, but they rarely cause serious problems.
There is no medical evidence that fevers from infection cause brain damage. The
body limits a fever caused by infection from rising above
41°C (106°F). But outside heat—such as from
being in a car that is parked in the sun—can cause body temperature to rise
above 41.7°C (107°F), and brain damage can
Childhood immunizations can reduce the risk for
fever-related illnesses, such as
Haemophilus influenzae type b (Hib) infection.
Although no vaccine is 100% effective, most routine childhood immunizations are
effective for 85% to 95% of the children who receive them. For more
information, see the topic
It is not unusual for a
preschool-aged child to have 7 to 10 viral infections in a year. Each new viral
infection may cause a fever. It may seem that a fever is ongoing, but if 48
hours pass between fevers, then the new fever is most likely from a new
Common causes of fever include:
Teething may cause a mild increase in your child's temperature. But if the temperature is higher than 38°C (100.4°F), look for symptoms that may be related to an infection or illness.
A fever that increases quickly may lead to a
fever seizure in some children. After a fever has
reached a high temperature, the risk of a seizure is less. Fever seizures can
be frightening to see, but they usually do not cause other problems, such as
intellectual disability, or learning problems. If your
child has a high fever and a seizure, see the topic
An abnormally low body temperature (hypothermia) can be serious, even life-threatening. Low body temperature may occur from cold exposure, shock, alcohol or drug use, or certain metabolic disorders, such as diabetes or hypothyroidism. A low body temperature may also be present with an infection, particularly in newborns, older adults, or people who are frail. An overwhelming infection, such as sepsis, may also cause an abnormally low body temperature.
child's symptoms to decide if and when your child should see a doctor.
Health Tools help you make wise health decisions or take action to improve your health.
Babies can quickly get dehydrated when they lose fluids because of problems like
vomiting or fever.
Symptoms of dehydration can range from mild to
severe. For example:
You have answered all the questions. Based on your answers, you may be
able to take care of this problem at home.
Many things can affect how your body responds to a symptom and what kind
of care you may need. These include:
You can get dehydrated when
you lose a lot of fluids because of problems like vomiting or fever.
Symptoms of dehydration can range from mild to severe. For
Temperature varies a little depending on how you measure it.
For children up to 11 years old, here are the ranges for high, moderate, and
mild according to how you took the temperature.
Oral (by mouth), ear, or rectal temperature
A forehead (temporal) scanner is usually 0.3 C (0.5 F) to 0.6 C (1 F) lower than an oral temperature.
Armpit (axillary) temperature
Note: For children under 5 years old, rectal temperatures are
the most accurate.
Symptoms of difficulty breathing in a baby or young child can range from mild to severe. For example:
Symptoms of difficulty breathing can range from mild to severe. For example:
A baby that is extremely sick:
A baby that is sick (but not extremely
Based on your answers, the problem may not improve without medical
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
You can use a small rubber bulb (called an aspirating bulb)
to remove mucus from your baby's nose or mouth when a
cold or allergies make it hard for the baby to eat, sleep, or breathe.
To use the bulb:
Don't do this more than 5 or 6 times a day. Doing it too often
can make the congestion worse and can also cause the lining of the nose to
swell or bleed.
Sudden drooling and trouble swallowing can be signs of a
serious problem called epiglottitis. This problem can
happen at any age.
The epiglottis is a flap of tissue at the back
of the throat that you can't see when you look in the mouth. When you swallow, it closes to keep food and fluids out of the
tube (trachea) that leads to the lungs. If the epiglottis becomes inflamed or
infected, it can swell and quickly block the airway. This makes it very hard to
The symptoms start suddenly. A person with epiglottitis
is likely to seem very sick, have a fever, drool, and have trouble breathing,
swallowing, and making sounds. In the case of a child, you may notice the child
trying to sit up and lean forward with his or her jaw forward, because it's
easier to breathe in this position.
Severe dehydration means:
Moderate dehydration means:
Mild dehydration means:
Based on your answers, you need
or other emergency services now.
Pain in children under 3 years
It can be hard to tell how much pain a baby or toddler is in.
Severe trouble breathing means:
Moderate trouble breathing means:
Mild trouble breathing means:
If you're not sure if a child's fever is high, moderate, or
mild, think about these issues:
With a high fever:
With a moderate fever:
With a mild fever:
Symptoms of serious illness in a baby
may include the following:
Symptoms of heatstroke may
Heatstroke occurs when the body can't control its own
temperature and body temperature continues to rise.
Sudden tiny red or purple spots or
sudden bruising may be early symptoms of a serious
illness or bleeding problem. There are two types.
Petechiae (say "puh-TEE-kee-eye"):
Purpura (say "PURR-pyuh-ruh" or “PURR-puh-ruh”):
Severe dehydration means:
Moderate dehydration means:
Mild dehydration means:
Based on your answers, you may need care soon. The
problem probably will not get better without medical care.
Fever can be a symptom of almost any type of infection.
Symptoms of a more serious infection may include the
Symptoms of serious illness may
Shock is a life-threatening condition that may occur quickly
after a sudden illness or injury.
Symptoms of shock in a child may include:
Many prescription and non-prescription medicines can trigger
an allergic reaction and cause a fever. A few examples are:
Certain health conditions and medicines weaken the immune system's ability to fight off infection and
illness. Some examples in children are:
Pain in children 3 years and older
It can be hard to know whether you
should call your doctor when your child has a
fever, especially during the cold and flu season. The
degree of the fever may not be related to the seriousness of the illness. The
way your child looks and acts is a better guide than the thermometer. Most
children will be less active when they have a fever.
If your child
is comfortable and alert, is eating well, is drinking enough fluids, is urinating normal
amounts, and seems to be improving, home treatment without medicine is all that
is needed for a fever. Dress your child
lightly, and do not wrap him or her in blankets. Dressing lightly will help
your child's body cool down.
Try these home treatment measures to make sure your child is drinking enough fluids and does not get dehydrated while he or she has a fever.
you see signs of dehydration in your baby. These signs include your baby being thirstier than usual and having less urine than usual.
Lowering your child's
temperature is important when the fever is causing discomfort. If your child is
Talk to your child's doctor before switching back and
forth between doses of acetaminophen and ibuprofen. When you switch between two
medicines, there is a chance your child will get too much medicine.
Call your child's doctor if any of the following occur during home
The best way to prevent fevers is to reduce
your child's exposure to infectious diseases.
Handwashing is the single most important prevention
measure for people of all ages.
To prepare for your appointment, see the topic Making the Most of Your Appointment.
You can help your
child's doctor diagnose and treat your child's condition by providing the
Other Works Consulted
Centigrade to Fahrenheit temperature conversions (2011). In MJ Hockenberry, D Wilson, eds., Wong's Nursing Care of Infants and Children, 9th ed., (inside back cover). St. Louis, MO: Mosby Elsevier.
ByHealthwise StaffPrimary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency MedicineJohn Pope, MD - PediatricsAdam Husney, MD - Family MedicineSpecialist Medical ReviewerDavid Messenger, MD
Current as ofMay 27, 2016
Current as of:
May 27, 2016
William H. Blahd, Jr., MD, FACEP - Emergency Medicine
& John Pope, MD - Pediatrics & Adam Husney, MD - Family Medicine & David Messenger, MD
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