A fever is an increase in normal body temperature. Healthy individuals typically have a body temperature of about 98.6 degrees Fahrenheit. The body temperature fluctuates by about one degree throughout the day. However, if a person's body temperature increases more than it normally does throughout the day, he/she has a fever. A person can usually recognize when he/she has a fever because it often causes symptoms, such as chills or sweating.
A fever is considered a sign of an underlying medical problem. Most fevers are caused by infections, such as the flu, pneumonia, or strep throat. Other common causes include extreme sunburn, exposure to hot environments, and certain medications. In rare cases, there may be no known underlying cause.
Fevers are usually not dangerous for adults, unless they are 103 degrees Fahrenheit or higher. For infants and very young children, even a slight increase in body temperature may indicate a serious infection. If a baby younger than 12 months old has a temperature higher than 100 degrees, a healthcare provider should be consulted immediately. Adults and children who have temperatures higher than 102 degrees that are not responding to medications, such as ibuprofen (Motrin®, Advil®), aspirin, or acetaminophen (Tylenol®), should visit their doctors.
Most fevers go away in a few days even without treatment. Additional treatments, such as antibiotics, may be necessary depending on the underlying cause of the fever.

Related Terms

Body temperature, cool compress, febrile seizure, fever of unknown origin, hyperthermia, immune response, infection, pyrogens, sponge bath.