Fever

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Medical Author:

John P. Cunha, DO, FACOEP

John P. Cunha, DO, FACOEP

John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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• Although a fever could be considered any body temperature above the normal 98.6 F (37 C), medically, a person is not considered to have a significant fever until the temperature is above 100.4 F (38.0 C).
• Most fever is beneficial, causes no problems, and helps the body fight off infections. The main reason for treating a fever is to increase comfort.
• Fever is the result of an immune response by your body to a foreign invader. These foreign invaders include viruses, bacteria, fungi, drugs or other toxins.
• Children under 3 months of age with a temperature of 100.4 F (38.0 C) or greater should be seen by a health care professional. They may be quite ill and not show any signs or symptoms besides a fever. Infants less than 6 weeks of age should be seen immediately by their doctor.
• Acetaminophen (Tylenol and others) and ibuprofen (Advil, Motrin) can be used to treat a fever. Aspirin should not be used in children or adolescents to control fever.
• The prognosis for a fever depends on the cause. Most cases of fever are self-limited and resolve with symptomatic treatment.
• A person who is taking immunosuppressant drugs or who has a history of or diagnosis of cancer, AIDS, or other serious illness, such as heart disease or diabetes, should seek medical care if a fever develops.

Fever refers to an elevation in body temperature. Technically, any body temperature above the normal oral measurement of 98.6 F (37 C) or the normal rectal temperature of 99 F (37.2 C) is considered to be elevated. However, these are averages, and one's normal body temperature may actually be 1 F (0.6 C) or more above or below the average of 98.6 F. Body temperature can also vary up to 1 F (0.6 C) throughout the day.

Fever is not considered medically significant until body temperature is above 100.4 F (38 C). Anything above normal but below 100.4 F (38 C) is considered a low-grade fever. Fever serves as one of the body's natural defenses against bacteria and viruses which cannot live at a higher temperature. For that reason, low fevers should normally go untreated, unless accompanied by troubling symptoms.

Also, the body's defense mechanisms seem to work more efficiently at a higher temperature. Fever is just one part of an illness, many times no more important than the presence of other symptoms such as cough, sore throat, fatigue, joint pains or aches, chills, nausea, etc.

Fevers of 104 F (40 C) or higher demand immediate home treatment and subsequent medical attention, as they can result in delirium and convulsions, particularly in infants and children.

Fever should not be confused with hyperthermia, which is a defect in your body's response to heat (thermoregulation), which can also raise the body temperature. This is usually caused by external sources such as being in a hot environment.