What Are Febrile (Fever) Seizures?

Medically Reviewed by Amita Shroff, MD on July 28, 2023
4 min read

If your child ever had a febrile (fever) seizure, it’s something you probably won’t forget. But while these look scary, usually there are no long-term effects.

Doctors aren’t certain about how it’s triggered. A temperature above 100.4 F may do it, or the seizure may be a result of how quickly your child’s fever spikes. You’re likely to notice the seizure, then feel that she’s burning up. It may be the first indication you have of her being sick.

Kids between 3 months and 6 years of age can get one. But they’re most common in toddlers between 12 and 18 months. Children usually outgrow them by the time they’re 6 years old.

Your child is more likely to get one if other people in your family have had one. A second febrile seizure also is more likely once your child has had the first one.

That depends on the type of febrile seizure.

Simple seizures: These are the most common and usually are over in a minute or two. But they can last as long as 15 minutes.

Symptoms include:

  • Convulsions – shaking and twitching all over the body
  • Fever of 100.4 or greater
  • Eye-rolling
  • Unresponsiveness
  • Moaning
  • Losing bowel or bladder control
  • Bleeding tongue or mouth from biting down

Your child may feel sleepy, irritable, cranky or confused for a few hours once it’s over.

Complex seizures: These are less common and can last longer than 15 minutes. Your child may have more than one in a day. Only one part of your child’s body may twitch or shake. Afterwards, her arm or leg may feel weak.

A complex febrile seizure is a greater concern. It may require additional examination, including lab work, imaging, a spinal tap or even a hospital admission

Any time your child has a temperature and is under the age of 6, a febrile seizure is possible. These are the most common reasons for a fever:

Infections: If your child picked up a bacterial or viral infection she may get a temperature. Roseola, also known as sixth disease, is often a culprit because it causes a fever to spike quickly.

Vaccinations: Fevers may follow some immunizations -- especially the one for measles, mumps and rubella (MMR). Your child may get a temperature 8 to 14 days after the shot.

Stay calm and act fast to prevent an injury:

  • Move your child to a safe place (like the floor) so she can’t fall.
  • Roll her onto her side so she doesn’t choke on saliva or vomit.
  • Don’t put anything in your child’s mouth.
  • Don’t hold her down or try to control the convulsions.

Call your doctor after it’s over as long as the seizure lasts less than a few minutes and your child is breathing/stable. Your child may need to be seen to find out what’s causing the fever.

Some children, especially babies under 12 months old, may need medical tests. Your doctor may want to make sure the fever is not caused by meningitis -- a serious infection in the brain’s lining.

Call 911 if:

  • The seizure lasts longer than 5 minutes.
  • Your child is having trouble breathing or is turning blue.
  • Just one part of the body is jerking or twitching.
  • Your child is acting odd an hour or more afterwards.
  • She looks dehydrated.
  • Another seizure happens within 24 hours.

About 32% of kids who’ve had a febrile seizure will get another within a year or two. Children who are younger than 15 months when they have the first one are more likely to have a repeat.

It won’t necessarily happen every time your child has a fever or at the same temperature as the first.

Your doctor may prescribe long-term anti-seizure medicine to give your child at home. That’s more likely after a complex seizure. One dose of diazepam gel put into your child’s bottom usually stops the convulsions. This is an acute seizure medication to administer if seizure lasts greater than 5 minutes. Call 911 to get emergency medical help, too.

Simple febrile seizures don’t cause brain damage or affect your child’s ability to learn. It’s not the same thing as epilepsy. That’s when a child has two or more seizures without a fever. Having febrile seizures only slightly raises your child’s chances (2%) of eventually getting epilepsy.

Your child should have normal development and learning after a simple febrile seizure. A simple febrile seizure should not cause any long-term consequences.