Fever in babies and kids

A fever is a higher-than-normal body temperature. It's a response to inflammation and is usually a sign that the body's immune system is responding – to a virus or bacteria, for example. But the fever itself isn't an illness, and it doesn't make an illness worse.

As long as you keep your baby or child hydrated, a fever usually isn't harmful and will eventually go away on its own, when the underlying cause is addressed.

Though it can be scary when your child has a fever, take some comfort in the fact that a fever means your child's immune system is doing its job. An elevated temperature may help your child fight infections more effectively, since it raises the body temperature to be less hospitable to bacteria and viruses. A fever also tells the body to make more white blood cells and antibodies to fight infection.

How to tell whether your baby or child has a fever

A fever is a temperature of 100.4 degrees F or higher. If your child has a fever, you'll decide what to do based on your child's age and other symptoms (see below).

You may get a slightly different reading depending on how you take your child's temperature. The most accurate method is a rectal reading. If your baby objects to having their temperature taken rectally, you can take their temperature under the armpit first. (This is called an axillary temperature.)

If their axillary temperature is above 99 degrees F and your baby is younger than 3 months old, do a rectal reading immediately. If your baby is 3 months or older and they're acting fine with an axillary temperature over 99 degrees F, it's okay to wait and retake their temperature with another armpit reading later – say, in 15 to 30 minutes. (If your child was over-bundled or running around, you might find the temperature has gone down.) If they're looking or acting unwell, though, then take a rectal temperature for accuracy right away.

Older children won't appreciate having their temperature taken rectally. Instead, use another method – such as an axillary (underarm) reading, temporal (across the forehead) reading, tympanic (ear) reading, or oral (mouth) temperature.

These methods are less accurate than a rectal reading, but they can be used for screening. If you call the doctor, tell them which method you used to take the temperature. If your child is acting fine and look fine, you don't need to call the doctor unless their temperature reaches 100.4 degrees F.

If your child's been active (crawling, cruising, running around), their temperature may be higher. It'll also change if they've been in the sun or the cold, swaddled, recently had a hot or cold beverage, or just taken a bath. Your child's temperature can change depending on the time of day, too. (It's often higher in the afternoon).

What's a normal baby temperature?

A normal baby temperature – taken rectally – runs from 97 degrees to 100.3 degrees F. The average baby temperature is 98.6 degrees F. A newborn baby temperature is a bit higher, averaging 99.5 degrees for the first 28 days.

A fever in a baby is 100.4 degrees F. A fever this high in an infant less than 3 months old is considered an emergency. For babies and toddlers 3 months to 36 months old, a temperature of 102.2 degrees F is considered a high fever.

These numbers are based on the most accurate readings, taken rectally.

What's a normal temperature for kids?

As with babies, a normal temperature for kids ranges from 97 degrees F to 100.3 degrees F. The average body temperature for a kid, though, is around 97.5 degrees F.

A rectal temperature of 100.4 degrees F or higher is considered a fever. (Other methods may give inaccurate numbers. When you call your child's doctor, be sure to tell them what method you used to take your child's temperature.)

For babies and children 36 months and older, a high fever is 103.1 degrees F or higher. A temperature of 104 degrees F or higher may be a symptom of heat stroke. Damage to organ systems is possible with temperatures of 105.8 F or higher.

Causes of fever

Many conditions can cause a fever, including inflammatory conditions and immune responses. Viral and bacterial illnesses can also cause a fever.

The most common illnesses that cause fever include:

• Colds
• Flu
• Ear infection
• Gastroenteritis
• Croup
• Bronchitis
• Urinary tract infection
• COVID-19
• Sore throat

There's no scientific evidence confirming that teething causes fevers, though many parents report fevers in their teething babies and toddlers.

No matter the cause, monitor your child closely when they have a fever. Be alert to other symptoms of illness, and report the fever and symptoms to your baby's doctor when appropriate (see below).

Some childhood immunizations (such as the DTaP, MMR, and COVID vaccines) can sometimes cause a fever as the body mounts an immune response.

When should you treat a fever?

To prevent dehydration, always treat your baby or child's fever with fluids, no matter their temperature and how they're feeling.

Other than keeping them hydrated, you only need to treat your child's fever if they're uncomfortable. If your child is older than 3 months and has a rectal temperature less than 102 degrees F (38.9 degrees C), and they are acting normally, they don't need you to treat the fever.

If your baby or child is very fussy or tired and unable to sleep, though, you may want to bring their fever down so they can rest. You may also want to bring the fever down if your child is listless or has muscle aches or a headache with their fever.

By the way, it's not always true that the higher the fever the sicker the child.

How to treat a fever in your baby or child

Medicine for fever is an option if the fever is making your child uncomfortable and your child's doctor says it's okay. Acetaminophen or ibuprofen will help bring down the fever. (Ibuprofen isn't recommended for babies under 6 months old or for children who are dehydrated or have persistent vomiting.)

When giving medicine:

• Be careful with the dose. Your child's weight will determine the right dose. Always use the measuring device that comes with the medicine to give your child exactly the right amount.
• Don't give fever-reducing medicine more often than is recommended. The directions will probably say that you can give acetaminophen every four hours (up to a maximum of five times per day) and ibuprofen every six hours (up to a maximum of four times per day).
• Never give your child aspirin. Aspirin can make a child more susceptible to Reye's syndrome, a rare but potentially fatal disorder.

Don't give your baby or young child over-the-counter cough and cold medicine. Most doctors don't recommend these products for babies and young children.

In addition to giving medication, here are some basic steps you can take to make a baby or older child comfortable:

Remove layers of clothing so your child can lose heat more easily through their skin. Dress them in one light layer. If they're shivering, give them an additional layer until they're warm again.

Place a cool, damp washcloth on your child's forehead while they rest.

Offer plenty of fluids. Nurse or bottle feed your baby often. Older babies and children can have chilled foods, such as ice pops and yogurt, to help cool the body from the inside out and keep them hydrated. Electrolytes for children – formulated to help rehydrate – are available in pharmacies. (Ask your doctor before giving electrolytes to a baby.)

Give your child a lukewarm tub bath or a sponge bath. As the water evaporates from your child's skin, it will cool them and bring their temperature down. Don't use cold water. It can make your child shiver and cause their body temperature to rise. Use tepid water (85 to 90 degrees) to wipe down your child's skin, particularly the forehead and underarms.

Don't use rubbing alcohol (an old-fashioned fever remedy). It can cause a temperature spike and possibly even alcohol poisoning.

Use a fan. Keep the fan at a low setting and aim it near your child to circulate the air around them rather than blow directly on them (so they don't get chilled).

Stay indoors in a cool place. Or, if you're outside, stay in the shade.

When is a fever dangerous?

Fever is usually a normal part of the body's healing process. But there are complications to be aware of – either because they can be dangerous or because they're frightening and you'll want to be prepared.

Febrile seizures

Fevers sometimes cause febrile seizures in babies and young children. They're most common in children between the ages of 6 months and 5 years.

In most cases, the seizures are harmless, but that doesn't make it any less terrifying if your child's having one. Your child may roll their eyes, drool, or vomit. Their limbs may become stiff and their body may twitch or jerk. Although the seizure itself is usually limited and not dangerous, it's important for your child's doctor to evaluate the cause of the fever.

Fever that keeps coming back

Fever-reducing medicine brings down body temperature temporarily, but it doesn't address the cause of the inflammation in the body. So your child may run a fever until their body is clear of the infection, if that's the cause. This can take at least two or three days. Your doctor may want to see your child if the fever lasts longer than three days.

If your child's fever lasts more than three days, they may be fighting a bacterial infection, which will need evaluation and possibly treatment with antibiotics.

Some infections, such as influenza (the flu), can last five to seven days. And if your child is being treated with antibiotics to fight a bacterial infection, it may take 48 hours for their temperature to fall.

Fever with no other symptoms

When a child has a fever that isn't accompanied by symptoms such as a runny nose, a cough, vomiting, or diarrhea, figuring out what's wrong can be difficult.

There are many viral infections that can cause a fever without any other symptoms. Some, such as roseola, cause three days of very high fever followed by a light pink rash on the trunk.

More serious infections, such as meningitis, urinary tract infections, or bacteremia (bacteria in the bloodstream), may also trigger a high fever without any other specific symptoms. If your child has a fever of 102.2 degrees F or higher for longer than 24 hours, or any fever over 100.4 degrees F without a clear cause for more than 3 days, call the doctor, whether or not they have other symptoms.

Note: Many parents worry that a high fever could cause brain damage in their baby or child. As scary as the idea is, the reality is extremely unlikely. For a fever to cause brain damage, it would need to climb over 107.6 degrees F. A fever caused by an infection won't usually climb over 105 degrees F.

When to call the doctor for a fever

If your baby is under 3 months old and has a temperature of 100.4 degrees F or higher, call the doctor immediately. A baby this young needs to be checked for serious infection or disease right away. Young babies don't show signs of severe infection like older babies do, so they can develop a full-fledged blood infection and not display the typical symptoms.

Also call the doctor if your baby under 3 months old has a temperature that's lower than 97 degrees F. Temperature fluctuations in any direction in a newborn can be a sign of a serious illness.

If their doctor isn't available, go to the emergency room. Don't give your baby fever medicine before going.

For babies 3 months and older, as well as toddlers and children, the most important thing is how they look and act. If your baby or child appears well, is drinking fluids, and has no other symptoms, there's no need to call the doctor unless the fever persists or reaches 104 degrees F or higher.

Also call the doctor if your baby or child has:

• A fever that lasts longer than 24 to 48 hours (if they're 2 years or younger) or 48 to 72 hours (if they're 3 years or older)
• Symptoms of an illness that may need to be treated, such as an ear infection, a urinary tract infection, or sore throat
• A recurring fever for more than a week, no matter the temperature
• A serious illness, such as sickle cell anemia or diabetes, or a weakened immune system.
• A new rash or bruises (small, purple-red spots that don't turn white or paler when you press on them, or large purple blotches, can signal a very serious bacterial infection)
• Signs of mild or moderate dehydration, such as fewer wet diapers or peeing less, fewer tears while crying, and a dry mouth
• Vomiting or diarrhea
• Breathing difficulty (or breathing faster than usual) even after you clear your baby's nose with a bulb syringe. This could indicate pneumonia or RSV.
• A brief seizure (less than two minutes)

Call 911 or your local emergency number, or take your child to the Emergency Department if your baby or child:

• Has a high fever (approaching 105 degrees) that's not responding to fever medication
• Has signs of respiratory distress (grunting, flaring nostrils, sucking in the skin above the collarbone or between or below the ribs, consistently fast breathing, whistling or wheezing while breathing)
• Seems drowsy, confused, and is suddenly unable to walk
• Is unable to wake up easily
• Has blue lips, tongue, or nails
• Has a stiff neck
• Has a prolonged seizure (two minutes or longer)
• Has signs of serious dehydration, such as sunken eyes; splotchy, cold hands and feet; excessive sleepiness or fussiness; lightheadedness, dizziness, or delirium; wrinkled skin

Again, fever is common, normal, and a sign your little one's body is doing what it's designed to do when faced with inflammation. But you're the best judge of when something is wrong. If you're concerned about what's happening with your child's temperature, call their doctor.

Learn more:

• When to call 911
• How can I get my child to drink more water?
• Teething remedies