When to Call a Doctor for Your Child’s Fever

By David Shafran, MD
Medically reviewed
June 9, 2021

All children get fevers from time to time. Although this can be concerning for a parent, in most cases, kids feel better within a few days. Still, fevers should be monitored closely because they can be a symptom of an underlying illness or infection.

It is important to remember that in almost all cases, a fever itself is not harmful; it is actually the sign of a healthy immune system acting appropriately in response to an illness.

To help you care for your child, in this article, I’ll describe the common symptoms and possible causes of fever in children as well as natural and medical treatment options. I’ll also explain when it’s important to call your doctor or take your child to the emergency room for a fever. With this information, you can keep your child safe and get them back to better health quickly.

What Is Considered a Fever in Children?

A child’s body temperature can vary depending on their age, activity level, or even time of day. A fever occurs when their body temperature rises above its normal level as a response to infection, illness, or another less serious cause such as wearing too many layers. 

The following guidelines indicate your child has a fever: 

  • Infant or child less than three months old: Any elevated temperature.
  • Children three months and older: Oral temperature of 100°F (37.8°C) or higher.
  • Children three months and older: Rectal temperature of 100.4°F (38°C) or higher.
  • Children three months and older: Axillary temperature (taken in the armpit) of 99°F (37.2°C) or higher.

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Symptoms of a Fever in Children

The first sign of a fever is an elevated temperature measured with a digital thermometer. In some cases, your child may have additional symptoms, including: 

  • Chills
  • Sweats
  • Reduced appetite
  • Low energy
  • Fussy or irritable mood

In many cases, a child’s behavior can be a reliable indicator as to whether the fever is the result of a minor illness or something more serious. For example, if your child is alert, drinking and urinating as normal, interested in playing, has a normal skin color, and responds well to medication or when their fever goes down, the fever is unlikely to be cause for concern.

When Is a Fever Too High for a Child?

Some symptoms may indicate that a child’s fever is a sign of a more serious illness. Based on your child’s age, if you observe any of these, call your doctor immediately:

Infant or child three months or younger

  • Rectal temperature of 100.4°F (38°C) or higher

Child three months or older

  • Temperature at or above 102.2°F (39°C)
  • Refusing liquids or not drinking enough
  • Persistent diarrhea or vomiting
  • Signs of dehydration such as peeing less frequently, having dark urine, crying without tears, and being less alert and active than normal
  • Another physical symptom, such as sore throat, earache, or ear infection
  • Fever for more than 24 hours (if younger than two years old) or more than 72 hours (if two years or older)
  • Child seems excessively sluggish, inactive or has reduced responsiveness to normal conversation and commands
  • Recurring fevers, even if they only last a few hours at a time
  • A chronic medical issue, such as heart disease, cancer, lupus, sickle cell disease, or a weakened immune system

Possible Causes of Fever in Children

Fevers can be caused by many things, some of which are not cause for concern:

  • Infection: The majority of fevers are caused by infection or illness, like the chickenpox and flu. Even a common cold can cause a mild fever in some children.
  • Immunizations or vaccines: Infants and young children can get a low-grade fever after receiving vaccinations.
  • Overdressing: Newborns in particular can develop fevers if they’re dressed in too many layers or in a hot environment because they don’t regulate body temperature as efficiently as older kids do. Still, have your pediatrician check your infant to be sure their fever isn’t something more serious.
  • Heat Exhaustion: Heat exhaustion can cause an unregulated rise in body temperature and fever.

Treatment of Fever in Children

Fevers in children don’t always require treatment. If you or your child’s doctor determines that the child’s fever is a result of a minor illness or infection, treatment is only necessary if the child has discomfort. 

How to reduce fever in children naturally

You can take several actions to help reduce your child’s fever naturally and ease their discomfort:

  • Keep your child hydrated: Even when it’s a symptom of a minor illness or infection, a fever can cause a child to lose more fluids quickly. Offering water, tea, and even popsicles can help them avoid dehydration. Be sure to avoid fluids with caffeine, which can increase the risk of dehydration. If your child has diarrhea or has been vomiting, ask your healthcare provider if you should give them an electrolyte solution to help replenish their fluids.
  • Let them rest: Encourage the child to take it easy if they’re not feeling well. Keeping them home, away from school or daycare, and well rested is the best way to allow their system time to recover.
  • Dress them in light, breathable clothing: Overdressing and overbundling can make it difficult for body heat to escape and in some cases cause a child’s temperature to rise. Instead, be sure to dress your child in lightweight, breathable clothing. If they’re sleeping, cover them with a light sheet or blanket as opposed to a heavier blanket or comforter. 

Best medicine for a fever in a child

You can give your child acetaminophen (Children’s Tylenol) or ibuprofen (Children’s Motrin) if they are particularly uncomfortable or fussy. Be sure to check the package for dosage recommendations based on their age and weight. Do not give your child aspirin, which has been associated with a rare but potentially fatal disease called Reye syndrome.

If you’re unsure about which medicine to give your child, or if your child is two years old or younger, call your pediatrician for their recommendation. 

When to take a child to the emergency room for a fever

An infant with any degree of fever should be taken seriously, and if their temperature is 100.4°F (38°C) or higher, seek immediate attention at the emergency room.

For older children, some behavioral or physical changes that may warrant immediate emergency care include: 

  • Rash or purple spots on their skin
  • Pain during urination
  • Inconsolable, incessant crying
  • Extreme irritability
  • Difficulty waking up or extreme fatigue
  • Blue lips, tongue, or nails
  • Stiff neck
  • Severe headache
  • Difficulty breathing that doesn’t get better after clearing nasal congestion
  • Febrile seizure
  • Severe belly pain
  • Limpness or refusal to move
  • Drooling
  • Fever above 104°F (40°C)

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When to See a Doctor

If you’re unsure about the cause of your child’s fever or whether it may be a sign of a more serious condition, call your doctor or healthcare provider for medical advice. 

How K Health Can Help

A fever in a child can cause worry and panic when you don’t know what’s going on. Did you know you can get affordable pediatric care with the K Health app? Download K to check your child’s symptoms, explore conditions and treatments, and text with a doctor in minutes.

Frequently Asked Questions

When is a fever too high for a child?
An infant or child 3 months old or younger with any elevated temperature should be taken seriously, but if your infant has a rectal temperature of 100.4°F (38°C) or higher, seek immediate emergency care. With older kids, call your doctor if they have a temperature of 102.2°F (39°C) or higher.
Why does my child only have a fever at night?
Body temperatures naturally rise at night, which is why a fever that is mild during the day can spike in the evening.
If your infant of 1 month or younger has a rectal temperature of 100.4°F (38°C) or higher, seek immediate emergency care. For older kids, behavioral or physical changes are often more accurate indicators of a serious condition. Signs that you should seek immediate emergency care for an older child with a fever include rash or purple spots on their skin; pain during urination; blue lips, tongue, or nails; severe headache, and seizure. If your child’s fever rises above 104°F (40°C), go to the nearest emergency room.
When should I take my child to the ER for a fever?
What is a low-grade fever in a child?
A low-grade fever is a slight elevation in body temperature that is rarely cause for concern. One common cause of low-grade fevers in children is immunizations.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

David Shafran, MD

Dr. Shafran is a board-certified pediatrics physician. He joins K Health from the Cleveland Clinic, where he led a pediatrics practice and completed a fellowship in transplant ethics. He has completed multiple fellowships, including one in pediatric nephrology at Rainbow, Babies & Children's University Hospitals. He received his medical degree from the Sackler School of Medicine in Tel Aviv and completed his medical residency at the Jacobi Medical Center.