What temp is dangerous for a child
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Your little one feels warm to the touch. After taking their temperature, you realize it’s 103°F — a fever!

Even if this scenario sounds super familiar, it can still catch you off guard. Before you race to the doctor, though, take a deep breath.

It’s helpful to familiarize yourself with fever, its function in the human body, and any warning signs that may mean it’s serious — or, alternatively, when you can relax.

Related: What you should do if your newborn has a cold

Normal body temperature is around 98.6°F, though it may fluctuate slightly higher or lower throughout the day. A fever starts with any temperature that reaches 100.4°F or above.

A temperature between 100.4°F and 102.2°F is considered a low-grade fever; a temperature above 102.2°F is considered a high fever.

A fever isn’t a sickness in itself. Instead, elevated body temperature is a sign that your child’s immune system is hard at work fighting off some type of invader — usually an illness or infection.

Along with an elevated temperature, your child may experience these fever symptoms:

The number on the thermometer isn’t always the best indicator of how sick your child is. You need to take into account:

  • your child’s age
  • how they’re acting
  • the number of days they’ve had the fever
  • any other symptoms you observe

For example, a small percentage of younger kids — usually between the ages of 6 months and 5 years, according to Mayo Clinic — may even experience febrile seizures. These seizures may involve jerking motions or look like your child is passing out.

Call your doctor if your child experiences a seizure or call 911 if the seizure lasts longer than 5 minutes.

In young babies, even slight temperatures may be a reason for concern. That’s why you should always contact your doctor or head to urgent care if your little one has any fever that’s 100.4°F or above. (The same goes with a temperature lower than 97.7°F when taken rectally.)

You should also head to the ER if your baby has a fever and any of the following symptoms:

  • trouble feeding
  • trouble breathing
  • unexplained rash
  • vomiting or diarrhea
  • acting differently (lethargic, inconsolable, etc.)

For the most accurate read, take your infant’s temperature with a digital thermometer inserted rectally (yes, that’s the best way). There’s some research to suggest that temporal artery thermometers can work accurately for this age as well, but speak with your doctor for guidelines.

Related: Baby fever 101: How to care for your child

In older babies and toddlers, call your doctor if your child’s fever is 102.2°F or above.

You’ll also want to pay attention to how your child responds to over-the-counter (OTC) medications. Always ask your pediatrician about giving any OTC drugs to babies under age 1.

If the fever doesn’t respond to fever reducers (ibuprofen, acetaminophen), there may be something more serious going on.

Other symptoms that warrant urgent care:

  • trouble waking up
  • trouble breathing
  • decreased urine output
  • difficulty keeping fluids down (vomiting)
  • unexplained dark rash
  • stiff neck, abdominal pain, or other concerns

Rectal reading may still be the best way to get an accurate temperature with older babies and toddlers. That said, you may also have success using a digital thermometer in the underarm or a temporal artery scanner.

If you have an in-ear thermometer, you’ll want to wait until your child is at least 6 months old to use it.

Related: Symptoms of fever in adults, children, and babies

For kids over age 3, a fever over 102° F that lasts for 2 or more days may be a reason for concern.

If their doctor tells you to keep an eye on it, a couple days may be OK.

However, if your little one has had a fever for 5 or more days, be sure to call back to make an appointment with their doctor. The same goes for a fever that doesn’t lower with OTC medications.

Other symptoms that may warrant urgent care:

  • trouble breathing or swallowing
  • difficulty keeping fluids down (vomiting)
  • burning with urination or infrequent urination
  • unexplained dark rash
  • stiff neck, abdominal pain, or other concerns
  • acting lethargic or difficult to wake

For children ages 4 and up, you may use a digital thermometer to take temperature orally under the tongue (if your child can hold it there long enough). For best results, be sure to wait 30 minutes after your child last ate or drank anything.

You may also take a reading in the ear or armpit — or even on the forehead using a temporal artery thermometer.

You know your child best. If you feel in your gut something is wrong, don’t hesitate to give your pediatrician’s office a call. And don’t feel silly — they get questions all the time and would rather you be extra safe when it comes to your child’s health.

Get in touch with your doctor or urgent care if:

  • Your baby is younger than 3 months old with a fever over 100.4°F.
  • Your baby (ages 3 to 6 months) has a temperature of 102°F and is acting unlike themselves (lethargic, uncomfortable, etc.).
  • Your older baby (ages 6 to 24 months) has a temperature over 102°F that lasts more than 1 day with no other signs of illness, like cough or diarrhea.
  • Your child’s fever has been present for 5 days or longer.
  • Your little one’s fever is 104°F or above, regardless of the presence of other symptoms.
  • Your child’s fever doesn’t lower even when taking fever reducers.
  • Your child is inconsolable, lethargic, or not acting like themselves.
  • Your little one is showing signs of dehydration, like decreased urine output. (FYI: Babies should wet at least 4 diapers per day; older kids should urinate at least once every 8 to 12 hours.)
  • Your child has recently had immunizations and has a fever of 102° F or higher.
  • Your child has recently had immunizations and has had an elevated temperature for more than 48 hours.
  • Your child has a febrile seizure. Call your doctor if it lasts less than 5 minutes. If longer, call 911.

Remember: You should always call your doctor for fever in babies under 3 months old.

Older kids do get fevers, though. So while it’s important to know when you should head to the doctor, it’s equally key to know when you can relax and monitor on your own.

In many cases, a fever is their body’s response to fighting off a mild illness. It will resolve on its own when the illness winds down and your child gets better.

You may be able to monitor at home if:

  • A fever lasts fewer than 3 to 5 days, provided your little one is acting like themselves. Observe their eating, drinking, and play patterns to see if they’re at their normal level of activity. Being slightly more tired than usual is expected, though.
  • The fever is below 102.5°F in children ages 3 months to 3 years or below 103°F in older kids. (Of course, this is provided there are no other warning signs.) Temperatures in this range are common and don’t necessarily signal an emergency.
  • Your child gets a low-grade fever following immunizations. A slight temperature in the first couple of days after shots isn’t necessarily a reason for concern.

Related: What are the flu symptoms in kids and how is it treated?

Chances are, your little one will have many fevers in their lifetime.

Pay attention to the number on the thermometer but also look at your child. If they’re acting normally and drinking enough fluids — and their fever goes away relatively quickly — you can relax and try at-home comfort measures, like giving them a lukewarm bath.

Otherwise, get in touch with your doctor or head to urgent care to get things checked out.