Viral infections, such as colds and
bacterial infections, such as a
urinary tract infection or
pneumonia, often cause a fever.
outside your native country can expose you to other diseases. Fevers that begin
after travel in other countries need to be evaluated by your doctor.
Fever and respiratory symptoms are hard 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
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.
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.
Check your symptoms to decide if and when
you should see a doctor.