Febrile seizures

Febrile seizures (sometimes called febrile convulsions) are fits that can happen when a child has a fever. They're most common between the ages of 6 months and 3 years.

It can be frightening to see your child having a seizure, especially if it's their first one. But the fits are usually harmless and almost all children make a complete recovery.

As a precaution, you may still need to take your child to the nearest hospital or dial 999 for an ambulance.

Signs of a febrile seizure

A febrile seizure usually lasts for less than 5 minutes.

During a febrile seizure, your child will:

  • become stiff and their arms and legs may begin to twitch
  • lose consciousness and may wet or soil themselves

They may also vomit or foam at the mouth and their eyes may roll back.

After the seizure, they may be sleepy for up to an hour. A straightforward febrile seizure will only happen once during your child's illness.

Complex febrile seizures

Sometimes the seizures can last longer than 15 minutes, and may only affect one area of your child's body. These are called complex febrile seizures. This type of seizure can happen again within 24 hours or while your child is ill.

What to do during a seizure

If your child is having a febrile seizure, put them in the recovery position. Stay with them and try to note how long the seizure lasts.

Important

Do not put anything into your child's mouth during a seizure, including medication or your fingers. There's a slight chance they might bite their tongue.

Immediate action required: Phone 999 or 112 or go to an emergency department (ED) if:

  • your child is having a seizure for the first time
  • the seizure lasts longer than 5 minutes
  • you think the seizure is caused by another serious illness, such as meningitis
  • your child is having breathing difficulties
  • your child does not wake up when the seizure stops

There may not be anything seriously wrong. But it's important to get them checked.

Driving to hospital

You might prefer to take your child to the hospital by car. Only do this if there are two adults present, one to drive and one to watch your child. Drive carefully, the most important thing is that everyone arrives safely.

When to contact your GP

Call your GP for advice if your child has had these seizures before and it lasts for less than 5 minutes. You should also contact your GP if they show signs of dehydration.

Read advice on managing dehydration in babies and children

Diagnosing febrile seizures

A doctor can often diagnose febrile seizures from a description of what happened. It's unlikely they'll see the seizure so it's useful to note:

  • how long the seizure lasted
  • what happened – such as body stiffening, twitches, staring, and loss of consciousness
  • whether your child recovered within an hour
  • whether they've had a seizure before

The doctor may do blood or urine tests if the cause of your child's illness is not clear.

Further tests

Sometimes your GP may recommend taking your child to the hospital. If their symptoms are unusual, they may need further tests and observation.

Tests your doctor may recommend include:

  • an electroencephalogram (EEG) – to check for epilepsy
  • a lumbar puncture – to check for an infection of the brain or nervous system

Your child might also need to go to the hospital if they're having complex febrile seizures. This is particularly true if they're younger than 12 months old.

Causes of febrile seizures

Febrile seizures are linked to the start of a fever, a high temperature of 38 degrees Celsius or above. The exact cause is unknown, although there may also be a genetic link.

Information:

The fever is usually due to an infection, such as chickenpox, flu or tonsillitis.

In rare cases, febrile seizures can occur after a child has a vaccination. A seizure after a vaccination does not increase the risk of having another seizure.

Recurring seizures

About a third of children who have a febrile seizure will have another one during a later infection. This often happens within a year of the first one.

Another seizure is more likely for your child if:

  • they were younger than 18 months old when the first seizure happened
  • there's a history of seizures or epilepsy in your family
  • before the first seizure, they had a fever for less than an hour
  • before the first seizure their temperature was under 40 degrees Celsius
  • they had a complex febrile seizure
  • they attend a creche or other childcare – this increases their chances of developing common childhood infections

Your child should not take regular medicines to prevent seizures. This is because the side effects of medicines often outweigh any risks of a seizure.

In some cases, your GP may recommend medication to take at the start of a fever. For example, if your child often has seizures when ill or has prolonged seizures.

Complications

Many parents worry that if their child has febrile seizures, they'll develop epilepsy.

While there is an increased risk of developing epilepsy, that risk is still small. Children with a history of simple febrile seizures have a 1 in 50 chance of epilepsy in later life. This is a 1 in 20 chance with complex febrile seizures.

People who have not had febrile seizures have around a 1 in 100 chance.

Sometimes parents worry that febrile seizures might cause brain damage. Even though febrile seizures are very frightening for parents, and can look very dramatic, they do not usually cause brain damage.

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This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 8.

Page last reviewed: 11 November 2021
Next review due: 11 November 2024

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