Fever in infants and children

, MD, Sidney Kimmel Medical College of Thomas Jefferson University

Normal body temperature varies from person to person and throughout the day. The normal body temperature is highest in preschool children. Several studies have shown that the maximum temperature tends to be in the afternoon and is highest in around 18 to 24 month old children, when many normal healthy children have a temperature of 38 ° C (101 ° F). However, fever is usually defined as a core body temperature (rectal) of ≥ 38.0 ° C (100.4 ° F)

Fever in adults – infections – msd manual edition for patients

September 6, 2018

Fever in adults

, MD, PhD, Warren Alpert Medical School of Brown University

Fever is an increased body temperature. A temperature is considered elevated if it is measured higher than 37.8 ° C orally or higher than 38.2 ° C rectally. Many people take the term "fever" very broadly and often mean that they feel too warm, too cold or sweaty, but they have not actually measured their temperature.

Although 37 ° C is considered a normal temperature, body temperature varies throughout the day. It is lowest in the morning and highest in the late afternoon, after which it can rise to 37.7 ° C. Even a fever never stays at a constant temperature. Sometimes the temperature peaks every day and then returns to normal – a process called intermittent fever. On the other hand, the temperature can fluctuate, but not fall back to normal – a process called remitting fever. Doctors no longer believe that the pattern of rising and falling fever is very important for the diagnosis of certain diseases.