When Is a Fever an Emergency in Children? Signs, Symptoms & Next Steps

Stuffed teddy bear with cloth over its forehead and thermometer under arm, fever emergency

This article was originally published in October 2025 and updated in April 2026 for relevance. 

While most fevers are not emergencies, some signs in children demand immediate care. This article by Andrew Carlson, MD, Division Head of Primary Care, outlines red flags, age-specific concerns, and what steps to take.
 

🚨 Is this an emergency? Start here:

Go to the ED now if your child:

Is under 3 months with a fever (100.4°F+)
Has trouble breathing, a seizure, or is unresponsive (call 911)

👉 Get care right away

Call your pediatrician or visit urgent care today if:

Fever is 102°F+ or lasting more than 2–3 days
Symptoms are getting worse

Not sure? Start with our full fever guide.

Emergency warning signs in children

If your baby or toddler shows any of the following signs along with a fever, you should seek medical care immediately:

Extreme lethargy or unresponsiveness

If your child is unusually sleepy, difficult to wake up, or not responding to your voice or touch, it’s a red flag. 

Difficulty breathing

Look for fast, labored, or shallow breathing. If your child’s chest is pulling in (retracting) with each breath, or if their lips or face look blue, call 911. Labored breathing can be caused by illnesses like respiratory syncytial virus (RSV) for which there is now a widely available monoclonal antibody. Also, know these emergency signs of respiratory distress. 

Seizures

A fever can sometimes trigger febrile seizures in young children. These seizures usually involve uncontrollable shaking or stiffening of the body, and they can be very alarming to witness. If your child has a seizure, lay them on their side, stay calm, and call your doctor. Many times, these need to run their course and are usually harmless in the long run.

Severe dehydration

This can get serious if your child isn't drinking fluids or is vomiting repeatedly. Signs include:

  1. Dry mouth or cracked lips
  2. Fewer than six wet diapers in 24 hours
  3. No tears when crying
  4. Sunken soft spot on a baby’s head
  5. Rashes and purple spots: a rash that doesn’t fade when pressed, or purple spots on the skin, could indicate a serious bacterial infection like meningitis. Get medical attention immediately
  6. Bulging or sunken soft spot: the soft spot on a baby's head can give you clues about their health. A bulging soft spot may mean increased pressure inside the skull, while a sunken soft spot is a sign of dehydration.
  7. Persistent crying or irritability: if your child can’t be soothed or cries in a high-pitched, unusual way, this may signal pain or distress beyond colic that needs attention.
  8. Stiff neck: if your child resists moving their neck or has trouble bending it forward, this could be a sign of meningitis and requires immediate medical attention.
  9. Fever lasting more than five days: a fever that persists for more than five days, even if it’s not very high, can indicate an underlying issue that needs medical investigation.

What fevers are most concerning by age?

For newborns younger than 3 months old, any fever is considered serious. Their immune systems are still developing, so even a low-grade fever could be a sign of a serious infection. 
 

When to contact your doctor

Call your doctor immediately if your baby is under 3 months old and has a fever of 100.4°F or higher.

For babies 3-6 months old, a fever higher than 101°F should also be checked by a doctor to rule out any possible bacterial infection. 
 
>>Related: Fevers: to worry, or not to worry?

 

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For newborns younger than 3 months old, any fever is considered serious. Their immune systems are still developing, so even a low-grade fever could be a sign of a serious infection. Call your doctor immediately if your baby is under 3 months old and has a fever of 100.4°F or higher.

Andrew Carlson, MD,
Medical Director, Primary Care, Connecticut Children's

Home care tips when fever isn't an emergency

If your child’s fever doesn’t show any of the emergency signs mentioned, you can try these steps at home:  

  • Keep them comfortable—dress your child in light clothing and keep the room at a comfortable temperature.
  • Encourage fluids—offer plenty of fluids like water, breast milk, or formula to prevent dehydration.
  • Ask your doctor if you can use fever-reducing medication—acetaminophen or ibuprofen can help lower a fever. Always follow the correct dosage based on your child’s weight and age—and always ask your doctor if this is your first rodeo.
  • Monitor their behavior—pay attention to how your child acts. If they’re drinking fluids, playing, and sleeping well, the fever is likely not serious.
     

Trust your instincts!
As a parent, you know your child best. If something doesn’t feel right, it’s always better to be cautions and call your doctor. Fevers are common but knowing when to worry can help you keep your baby or toddler safe and healthy.