It is defined as a rectal temperature of over 100.4 degrees F. or and oral temperature of over 99.5 degrees. We now think that fever may be one of the body s mechanisms to switch on the immune system to fight the infection. In fact, centuries ago before antibiotics, some illnesses were treated by an artificially produced fever. Fevers are most commonly caused by viral infections. These fevers usually last no more than three days.
Fever occurs when there is a rise in the hypothalamic set point.
In other words, the body s thermostat has been raised by infection, or when the body s heat production or environmental heat is greater than the body s capacity to get rid of it, or when the heat loss mechanisms are defective. Teething is commonly known to produce fever, however, never over 101 degrees. Fever in children is common because kids catch a lot of viral illnesses. Additionally, everyone s temperature fluctuates during the day. A mild rise in temperature can be due to exercise, too much clothing, a hot bath, or hot weather.