A fever in a healthy child is usually not dangerous, especially if the child does not have other symptoms and the fever goes away in 3 to 4 days. Most children who have a fever will be fussy and play less and may not eat as much as usual.
High fevers may make your child uncomfortable, but they rarely cause serious problems. There is no medical evidence that fevers from infection cause brain damage. The body limits a fever caused by infection from rising above 106°F (41.1°C). But outside heat-such as from being in a car that is parked in the sun-can cause body temperature to rise above 107°F (41.7°C), and brain damage can occur.
Childhood immunizations can reduce the risk for fever-related illnesses, such as Haemophilus influenzae type bHaemophilus influenzae (Hib) infection. Although no vaccine is 100% effective, most routine childhood immunizations are effective for 85% to 95% of the children who receive them. For more information, see the topic Immunizations.
It is not unusual for a preschool-aged child to have 7 to 10 viral infections in a year. Each new viral infection may cause a fever. It may seem that a fever is ongoing, but if 48 hours pass between fevers, then the new fever is most likely from a new illness.
Common causes of fever include:
Teething does not cause a fever. If a baby is teething and has a fever, look for other symptoms that may need to be evaluated.
A fever that increases quickly may lead to a fever seizure in some children. After a fever has reached a high temperature, the risk of a seizure is less. Fever seizures can be frightening to see, but they usually do not cause other problems, such as brain damage, intellectual disability, or learning problems. If your child has a high fever and a seizure, see the topic Fever Seizures.