Child Fever: When to Worry and When to Wait
Last updated September 10, 2026.
Fever itself is not dangerous. It is the body fighting infection. The number on the thermometer matters less than how your child acts. Under 3 months old, any fever of 100.4°F or higher needs same-day medical attention. For older children, go to the ER if your child has trouble breathing, won't wake up, has a seizure, or shows signs of dehydration.
Age matters most: under 3 months is different
A baby under 3 months old with a rectal temperature of 100.4°F or higher needs to see a doctor the same day. Call your pediatrician immediately or go to the ER. Newborns have immature immune systems and fever can signal serious infection.
Between 3 months and 3 years, fever over 102°F lasting more than two days warrants a call to the pediatrician. After age 3, the height of the fever matters even less. Focus on how your child looks and acts.
Always take a rectal temperature for babies under 3 months. For older infants and toddlers, rectal or temporal artery thermometers are most accurate. Oral thermometers work for kids over 4 who can hold one under the tongue.
Behavior tells you more than the thermometer
A child with 103°F who is playful, drinking fluids, and making eye contact is safer than a child with 100°F who is listless and won't respond. Watch for alertness, ability to drink, and whether your child can be comforted.
Red flags include extreme fussiness or inconsolable crying, refusal to drink anything for several hours, no tears when crying, fewer than four wet diapers in 24 hours, or a sunken soft spot on an infant's head. These signal dehydration.
If your child smiles at you, plays a little between sleep, and takes sips of water or breastmilk, you can usually manage fever at home. Acetaminophen or ibuprofen bring comfort but do not treat the underlying cause.
When to go to the ER
Call 911 or go to the emergency room if your child has a seizure, has trouble breathing or is breathing very fast, turns blue or gray, will not wake up or is very hard to wake, has a stiff neck, or has a rash that looks like purple or red spots that do not fade when you press on them.
Also go to the ER if your child is under 3 months with any fever, or if any child has a fever that returns after being gone for more than 24 hours. Returning fever can mean a secondary infection.
Severe headache, repeated vomiting, severe belly pain, or a child who looks or acts very sick also warrant emergency care. Trust your instinct. You know your child.
When to call the pediatrician
Call your child's doctor during office hours if fever lasts more than three days, if your child is between 3 months and 3 years with fever over 102°F for more than two days, or if you see no improvement after 48 hours.
Also call if your child has pain that is not relieved by acetaminophen or ibuprofen, a sore throat lasting more than two days, ear pain, or a fever after recent travel or known exposure to illness.
Many pediatricians offer nurse lines or after-hours advice. Community health centers provide low-cost or free pediatric care if you do not have insurance. Find one at findahealthcenter.hrsa.gov.
What to do at home
Keep your child hydrated. Offer water, breastmilk, formula, or an oral rehydration solution like Pedialyte. Avoid juice or soda, which can worsen diarrhea if present.
Dress your child in light clothing. A heavy blanket or too many layers traps heat. Room temperature should be comfortable, around 68 to 72°F. Sponging with lukewarm water can help if fever is very high, but do not use cold water or alcohol.
Acetaminophen can be given to infants over 2 months old. Ibuprofen is safe after 6 months. Follow dosing instructions by weight, not age. Never give aspirin to a child under 18, as it can cause a rare but serious condition called Reye syndrome.
Cost and access
Urgent care visits for a child with fever typically run $150 to $250 without insurance. ER visits can exceed $1,000. If cost is a concern, call your pediatrician first or use a community health center.
Most health insurance plans, including Medicaid and CHIP, cover well-child visits and sick visits with low or no copay. If your child is uninsured, contact your state's CHIP program through healthcare.gov or call 211 for local resources.
Telemedicine can be a starting point for older children with mild symptoms. Some plans cover virtual urgent care for around $50. It is not appropriate for infants under 3 months or for any child with red flag symptoms.
Common questions
What temperature is considered a fever in a child?
A rectal temperature of 100.4°F or higher is a fever. For older children, 100.4°F oral or 99°F armpit also counts. Rectal is most accurate for babies. Forehead strip thermometers are not reliable.
Should I wake my child to give fever medicine?
No. If your child is sleeping comfortably, let them sleep. Fever itself is not harmful and sleep helps the body heal. Give medicine when your child wakes if they seem uncomfortable.
Can teething cause a fever?
Teething may cause a slight rise in temperature, but not a true fever over 100.4°F. If your baby has a fever, look for other signs of illness like cold symptoms, fussiness, or changes in eating. Do not assume it is only teething.
How long does a typical fever last?
Most fevers from common viral infections last two to three days. If fever continues beyond three days or keeps returning, call your pediatrician. Bacterial infections may need antibiotics.
What if my child has a febrile seizure?
Febrile seizures happen in about 2 to 5 percent of children between 6 months and 5 years. They look frightening but rarely cause harm. If your child has a seizure, place them on their side on the floor, do not put anything in their mouth, and call 911. Most seizures stop in under five minutes.
Can I give my child both acetaminophen and ibuprofen?
You can alternate acetaminophen and ibuprofen if fever is very uncomfortable and one medicine alone does not help, but ask your pediatrician for guidance on timing and dosing. Do not give both at the same time. Overdosing either medicine can cause liver or kidney damage.
Sources
Pymander is not a replacement for a physician and does not provide medical advice, diagnosis, or treatment.