Fever is
the body's normal and healthy reaction to infection and other illnesses, both
minor and serious. It helps the body fight infection. Fever is a symptom, not a
disease. In most cases, having a fever means you have a minor illness. When you
have a fever, your other symptoms will help you determine how serious your
illness is.
Temperatures in this topic are oral temperatures. Oral temperatures are usually taken in older children and
adults.
Normal body temperature
Most people have an average
body temperature of about
98.6
°F (37
°C), measured orally
(a thermometer is placed under the tongue). Your temperature may be as low as
97.4
°F (36.3
°C) in the morning
or as high as 99.6
°F (37.6
°C)
in the late afternoon. Your temperature may go up when you exercise, wear too
many clothes, take a hot bath, or are exposed to hot weather.
Fever temperatures
A fever is a high body
temperature. A temperature of up to
102
°F (38.9
°C) can be helpful
because it helps the body fight infection. Most healthy children and adults can
tolerate a fever as high as
103
°F (39.4
°C) to
104
°F (40
°C) for short periods
of time without problems. Children tend to have higher fevers than
adults.
The degree of fever may not indicate how serious the
illness is. With a minor illness, such as a cold, you may have a temperature,
while a very serious infection may cause little or no fever. It is important to
look for and evaluate other symptoms along with the fever.
If you
are not able to measure your temperature with a thermometer, it is important to
look for other symptoms of illness. A fever without other symptoms that lasts 3
to 4 days, comes and goes, and gradually reduces over time is usually not a
cause for concern. When you have a fever, you may feel tired, lack energy, and
may not eat as much as usual. High fevers are not comfortable, but they rarely
cause serious problems.
Oral temperature taken after smoking or
drinking a hot fluid may give you a false high temperature reading. After
drinking or eating cold foods or fluids, an oral temperature may be falsely
low. For information on how to take an
accurate temperature, see the topic
Body Temperature.
Travel
outside your native country can expose you to other diseases. Fevers that begin
after traveling in other countries need to be evaluated by your health
professional.
Fever and respiratory symptoms are difficult to
evaluate during the flu season. A fever of
102
°F (38.9
°C) or higher for 3
to 4 days is common with the flu. For more information, see the topic
Respiratory Problems, Age 12 and Older.
Recurrent fevers are those that occur 3 or more times within 6 months and
are at least 7 days apart. 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
fever is recurring. If you have frequent or recurrent fevers, it may be a
symptom of a more serious problem. Talk to your doctor about your fevers.
Treating a fever
In most cases, the illness that
caused the fever will clear up in a few days. You usually can treat the fever
at home if you are in good health and do not have any medical problems or
significant symptoms with the fever. Make sure that you are taking enough foods
and fluids and urinating in normal amounts.
Review the Emergencies and Check Your Symptoms sections
to determine if and when you need to see a health professional.
If the person
feels hot and is sweating but does not have a fever, he or she may be having
symptoms of a heart attack. If symptoms of a heart
attack are present and the person is awake, alert, not vomiting, and not
allergic to aspirin, have the person chew and swallow one adult-strength (325
mg) or 2 to 4 low-dose (81 mg)
aspirin. Be sure to tell the emergency medical
personnel that an aspirin was taken and when it was taken. See the topic
Chest Pain.
Check Your Symptoms
If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.
Review
health risks that may increase the seriousness of your
symptoms.
Note:
Temperatures in this topic are
oral temperatures (a thermometer is placed under the
tongue).
Be sure to take your temperature before answering the
following questions. For information on how to take an
accurate temperature, go to the topic
Body Temperature.
If you are unable to
measure your temperature, look for other symptoms and answer the questions
below.
Review
health risks that may increase the seriousness of your
symptoms.
Note:
Be sure to try home treatment when you
or your child has a fever. Sometimes home treatment is all that is needed to
help lower a fever and help you or your child feel better.
Call your health professional immediately if you answer "Yes" to
any of the following questions.
Review
health risks that may increase the seriousness of your
symptoms.
Note:
Be sure to try home treatment when you
or your child has a fever. Sometimes home treatment is all that is needed to
help lower a fever and help you or your child feel better.
Call your health professional today if you answer "Yes" to
any of the following questions.
Do you think your fever may be caused by a
medicine?
Note:
If your answer is "Yes":
Call the health professional who
prescribed the medicine to determine if you should stop taking the medicine or
take a different one. An appointment may not be necessary.
If you
are taking a nonprescription medicine, stop taking the medicine. Call your
health professional if you feel you need to continue taking the
medicine.
Did
a fever begin within 3 weeks of receiving an immunization?
Note:
Some immunizations may cause a fever.
If your health professional has
given you instructions on how to treat your fever after an immunization, follow
those instructions.
If your fever continues after home treatment,
call your health professional.
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
Other Symptoms to Watch For
Because fever is only a symptom of another problem,
a careful evaluation of your health may help you identify the cause of your
fever. Often the importance of a fever can be determined only when other
symptoms are evaluated. Do you have any of the following symptoms or
problems?
If the person
feels hot and is sweating but does not have a fever, he or she may be having
symptoms of a heart attack. If symptoms of a heart
attack are present and the person is awake, alert, not vomiting, and not
allergic to aspirin, have the person chew and swallow one adult-strength (325
mg) or 2 to 4 low-dose (81 mg)
aspirin. Be sure to tell the emergency medical
personnel that an aspirin was taken and when it was taken. See the topic
Chest Pain.
Check Your Symptoms
If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.
Review
health risks that may increase the seriousness of your
symptoms.
Note:
Temperatures in this topic are
oral temperatures (a thermometer is placed under the
tongue).
Be sure to take your temperature before answering the
following questions. For information on how to take an
accurate temperature, go to the topic
Body Temperature.
If you are unable to
measure your temperature, look for other symptoms and answer the questions
below.
Review
health risks that may increase the seriousness of your
symptoms.
Note:
Be sure to try home treatment when you
or your child has a fever. Sometimes home treatment is all that is needed to
help lower a fever and help you or your child feel better.
Call your health professional immediately if you answer "Yes" to
any of the following questions.
Review
health risks that may increase the seriousness of your
symptoms.
Note:
Be sure to try home treatment when you
or your child has a fever. Sometimes home treatment is all that is needed to
help lower a fever and help you or your child feel better.
Call your health professional today if you answer "Yes" to
any of the following questions.
Do you think your fever may be caused by a
medicine?
Note:
If your answer is "Yes":
Call the health professional who
prescribed the medicine to determine if you should stop taking the medicine or
take a different one. An appointment may not be necessary.
If you
are taking a nonprescription medicine, stop taking the medicine. Call your
health professional if you feel you need to continue taking the
medicine.
Did
a fever begin within 3 weeks of receiving an immunization?
Note:
Some immunizations may cause a fever.
If your health professional has
given you instructions on how to treat your fever after an immunization, follow
those instructions.
If your fever continues after home treatment,
call your health professional.
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
Other Symptoms to Watch For
Because fever is only a symptom of another problem,
a careful evaluation of your health may help you identify the cause of your
fever. Often the importance of a fever can be determined only when other
symptoms are evaluated. Do you have any of the following symptoms or
problems?
If a visit to a health professional is not needed immediately, see the Home Treatment section for self-care information.
Home Treatment
It is easy to become dehydrated when
you have a
fever. Watch for
early signs of dehydration and
drink extra fluids, especially water. Adults should
drink at least 10 glasses of liquid a day to replenish lost fluids. Children
between the ages of 4 and 10 should drink at least 6 to 10 glasses. You may
feel better if you eat light, easily digested foods, such as soup.
Many people find that taking a lukewarm [80
°F (27
°C) to
90
°F (32
°C)]
shower or bath makes
them feel better when they have a fever. Do not try to take a shower if you are
dizzy or unsteady on your feet. Increase the water temperature if you start to
shiver. Shivering is a sign that your body is trying to raise its temperature.
Do not use rubbing alcohol, ice, or cold water to cool
your body.
Dress lightly when you have a fever. This will help
your body cool down. Wear light pajamas or a light undershirt. Do not wear very
warm clothing or use heavy bed covers. Keep room temperature at
70
°F (21
°C)
or lower.
If you are unable to measure your temperature,
you need to look for other symptoms of illness every hour while you have a
fever and follow home treatment measures.
Medicine you can buy without a prescription
Try a nonprescription
medicine to help treat your fever or pain:
Aspirin (also a nonsteroidal
anti-inflammatory drug), such as Bayer or Bufferin
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.
Safety tips
Be sure to follow
these safety tips when you use a nonprescription medicine:
Carefully read and follow all
directions on the medicine bottle and box.
Do not take more than
the recommended dose.
Do not take a medicine if you have had an
allergic reaction to it in the past.
If
you have been told to avoid a medicine, call your doctor before you take
it.
If you are or could be pregnant, do not take any medicine other
than acetaminophen unless your doctor has told you to.
You have
signs of dehydration and you are unable to drink
enough to replace lost fluids.
Fever lasts longer than 4
days.
Other symptoms develop, such as pain in one area of the body,
a cough, or urinary symptoms.
Fever recurs more than once over 3
weeks.
Symptoms become more severe or frequent.
Prevention
The best way to prevent fevers is to reduce
your exposure to infectious diseases.
Hand-washing is the single most important prevention
measure for people of all ages.
Centers for Disease Control and Prevention, Travelers'
Health
1600 Clifton Road, N.E.
Atlanta, GA 30333
Phone:
1-877-FYI-TRIP (1-877-394-8747) toll-free
Web Address:
www.cdc.gov/travel
The CDC's Travelers' Health Web site provides health information
for the traveler. The Web site provides information on immunizations that are
needed for travel to various areas of the world. It also provides information
for safe travel, including traveling with children and people with special
needs. Information about current outbreaks of disease in the world is also
provided. The CDC is the leading federal agency for protecting U.S. citizens'
health and safety by providing credible health information and health
promotion.
This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.