This blog is part of a series of blog posts designed to serve as a quick reference guide. Each will focus on a sudden injury or illness and is designed to help you make an informed decision on a plan of action when the unexpected happens.
A fever is the temporary increase in body temperature in response to a disease or illness. It’s important to remember that a fever is not an illness, but a sign that the immune system is fighting off a bacterial or viral infection. Most of the illnesses that cause a fever aren’t dangerous and treatable at home.
What is considered a fever?
Your child officially has a fever when the thermometer reads 100.4 F and above. An adult probably has a fever when the temperature is above 99°F to 99.5°F (37.2°C to 37.5°C), depending on the time of day.
When should I call the doctor?
How your child acts and feels is usually a better indicator than the number on the thermometer of how sick he or she is. The illness is probably not serious if your child is still eating and drinking, is alert, and is still interested in playing. If your child is lethargic, irritable, has a sore throat, has ear or stomach pain, or has pain when urinating, call your doctor. Also call the doctor for any fever that lasts longer than 24 to 48 hours in children under age two or 48 to 72 hours in an older child or adult.
You should also call the doctor right away if your child
- Is 3 months or younger and has a rectal temperature of 100.4°F (38°C) or higher.
- Is 3 to 12 months old and has a fever of 102.2°F (39°C) or higher.
- Has a fever of 105°F (40.5°C) or higher, unless it comes down readily with treatment and he or she is comfortable .
- Has a seizure. About four percent of children under the age of five have febrile seizures. While scary, they’re rarely serious. However, the first time a seizure occurs, the child should be evaluated immediately.