biology of infectious disease
infections
Fever in Adults
Fever is an elevated body temperature that occurs when the body's thermostat (located in the Endocrine Glands in the brain) resets at a higher temperature, primarily in response to an infection. Elevated body temperature that is not caused by a resetting of the temperature set point is called Although 98.6°F (37°C) is considered normal temperature, body temperature varies throughout the day. It is lowest in the early morning and highest in the late afternoon—sometimes reaching 99.9°F (37.7°C). Similarly, a fever does not stay at a constant temperature. Sometimes temperature peaks every day and then returns to normal. This process is called intermittent fever. Alternatively, temperature varies but does not return to normal. This process is called remittent fever. Doctors no longer think that the pattern of the rise and fall of fever is very important in the diagnosis of certain disorders. Body temperature can be measured at several areas of the body. The most common sites are the mouth (oral) and rectum. Other sites include the ear, forehead, and, much less preferably, armpit. Temperature is typically measured using a digital thermometer. Glass thermometers containing mercury are no longer recommended because they can break and expose people to mercury. Oral temperatures are considered elevated when They are higher than 99°F (37°C) in the early morning. They are higher than 100.4° F (38° C) at any time after the early morning. They are higher than a person’s known normal everyday temperature. Rectal and ear temperatures are about 1.0° F (0.6° C)higherthan oral temperatures. Skin temperatures (for example, the forehead) are about 1.0° F (0.6° C)lowerthan oral temperatures. Many people use the term “fever” loosely, often meaning that they feel too warm, too cold, or sweaty, but they have not actually measured their temperature. The ability to generate a fever is reduced in certain people (for example, those who are very old, very young, or who have an alcohol use disorder). (See also Overview of Infectious Disease and 