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- Fever facts
- What is a fever?
- What causes a fever?
- What are the signs and symptoms of a fever?
- How do health-care professionals diagnose a fever?
- How should someone take a temperature for fever?
- What is the treatment for a fever?
- What are home remedies for a fever?
- When should someone seek medical care for a fever?
- What kind of doctors treat a fever?
- What are complications of a fever?
- What is the prognosis for a fever?
- Is it possible to prevent a fever?
- Where can people find more information about fevers?
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What is a fever?
The definition of fever is an elevation in body temperature or a high body temperature. Technically, any body temperature above the normal oral measurement of 98.6 Fahrenheit (37 Celsius) or the normal rectal temperature of 99 F (37.2 C) is considered 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), which is the temperature considered to be a fever by medical professionals. 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 that cannot live at a higher temperatures. For that reason, low-grade fevers should normally go untreated, unless accompanied by troubling symptoms or signs.
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, sinus congestion, fatigue, joint pains or aches, chills, nausea, etc.
Fevers of 104 F (40 C) or higher may be dangerous and demand immediate home treatment and prompt medical attention, as they can result in delirium and convulsions, particularly in infants, children, and the elderly.
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. Heat exhaustion and heat stroke are forms of hyperthermia. Other causes of hyperthermia can include side effects of certain medications or medical conditions.
Fever should also not be confused with hot flashes or night sweats due to hormonal changes during perimenopause (the time period around menopause). Hot flashes and night sweats cause a sudden and intense feeling of heat, and may be accompanied by flushing (skin redness and tingly feeling) and sweating, but are not the same thing as a fever.