Cold and flu season means many parents will soon be reaching for the thermometer in the middle of the night. A fever can be scary, but in most children it is a sign that the body is fighting an infection, not a danger in itself. Knowing what counts as a fever, how age changes the rules and which warning signs need prompt attention can help you stay calm and make good decisions. This guide is based on advice from the American Academy of Pediatrics (AAP). It is not a substitute for medical care; when in doubt, call your child’s pediatrician.
What Counts as a Fever
For children, a temperature of 100.4°F (38.0°C) or higher is generally considered a fever. Normal body temperature varies a little through the day and with activity, so a reading slightly above 98.6°F is not necessarily a fever.
How you measure matters. Ask your pediatrician which method is best for your child’s age. For young babies, rectal readings are generally considered the most accurate. For older children, oral, ear and forehead thermometers are commonly used. Always use a digital thermometer, follow the instructions, and note the reading, method and time so you can report them accurately.
Age Matters Most: The AAP’s Guidelines
The younger the child, the lower the threshold for calling the doctor. According to the AAP:
- Under 3 months: call your pediatrician right away for a temperature of 100.4°F (38.0°C) or higher, even if your baby seems fine. Very young infants can have serious infections with few other signs.
- Under 2 years: call if a fever lasts more than 24 hours.
- 2 years and older: call if a fever lasts more than 3 days (72 hours).
- Any age: call if the temperature repeatedly rises above 104°F (40°C).
Warning Signs That Need Prompt Care
How your child looks and acts often tells you more than the number on the thermometer. The AAP advises calling your pediatrician right away if your child has a fever and:
- Looks very ill, is unusually drowsy or is very fussy
- Has been in a very hot place, such as an overheated car
- Has a stiff neck, severe headache, severe sore throat or severe ear pain
- Has trouble breathing
- Has an unexplained rash
- Has repeated vomiting or diarrhea
- Has had a seizure
- Has a weakened immune system, such as from sickle cell disease, cancer or medicines like steroids
- Has a heart problem
Also call if your child still seems sick after the fever comes down, or seems to be getting worse. If your child is struggling to breathe, is limp or unresponsive, or has blue or gray lips, call 911.
Comfort Care at Home
When your pediatrician agrees it is safe to manage a fever at home, focus on comfort and hydration:
- Fluids: offer water, breast milk or formula often. Watch for signs of dehydration, such as fewer wet diapers, dry mouth or no tears when crying.
- Rest and light clothing: dress your child in light layers and keep the room comfortable. Avoid bundling, which can trap heat.
- Observe behavior: the AAP notes that a child who plays and interacts after the fever is brought down is a reassuring sign.
- Ask before giving medicine: fever medicines are not always needed. Ask your pediatrician or pharmacist whether medicine is appropriate and which product and dose fit your child’s age and weight. Never give aspirin to children unless a doctor specifically tells you to.
Myths to Let Go Of
- “High fevers cause brain damage.” Fevers from infections do not usually rise high enough to cause harm. The concern is the underlying illness, which is why the warning signs above matter.
- “The fever must come down to normal.” The goal of treatment is comfort, not a perfect number.
- “Cold baths or rubbing alcohol help.” These can cause shivering and discomfort, and alcohol can be absorbed through the skin. Avoid them.
About febrile seizures
Some young children have a brief seizure with a fever. It is frightening to see, and any first seizure needs medical evaluation. Place your child on their side on a safe surface, do not put anything in their mouth and call for help.
Prepare Before Illness Strikes
Save your pediatrician’s after-hours number in your phone, find out whether your practice has a nurse advice line and know where the nearest urgent care and pediatric emergency department are. Keep a working digital thermometer at home and check that batteries are fresh.
What to Have Ready When You Call
Pediatric offices and nurse lines can help you faster if you have key details at hand. Before calling, note your child’s age and approximate weight, the highest temperature and how it was measured, when the fever started and any other symptoms, such as cough, rash, vomiting, diarrhea or ear pain. Note how much your child has been drinking, how often they have urinated or had wet diapers, and whether they are alert and playing. Have a list of any medicines already given, with the time and amount, plus any chronic conditions and allergies. If your child has been around someone who is sick, or you have recently traveled, mention that too. Keep a pen and paper nearby to write down instructions, and ask when you should call back if things change.
FAQ
Should I wake my child to check their temperature?
Generally, a sleeping child who is breathing comfortably can be left to rest. Ask your pediatrician for specific advice, especially for infants.
Are forehead thermometers accurate?
They can be convenient for screening, but accuracy varies. Ask your pediatrician which method is best for your child’s age.
When can my child return to school or child care?
Policies vary, but many schools require children to be fever-free for at least 24 hours without fever-reducing medicine. Check your school’s rules.
Sources
- HealthyChildren.org (AAP): Fever and Your Child: When to Call the Pediatrician
- NHS: High Temperature (Fever) in Children
Featured image: Shixart1985 / Wikimedia Commons, CC BY 2.0