Febrile seizures - Symptoms 

Symptoms of febrile seizures  

The main symptom of a febrile seizure is a fit that occurs while a child has a fever.

Febrile seizures often occur during the first day of a fever, which is defined as a high temperature of 38ºC (100.4ºF) or above. 

However, there appears to be no direct connection between the extent of your child’s fever and the start of a seizure. Seizures can develop even if your child has a mild fever, and may not develop at all with an extremely high temperature.

Simple febrile seizures can sometimes occur at the time of a rapid rise in temperature. In these cases, it is common to only realise that your child is ill when they have the seizure.

Alternatively, seizures can occur as your child’s temperature drops from a previously high level.

During simple febrile seizures, your child’s body will become stiff and their arms and legs will begin to twitch. They will lose consciousness and they may wet or soil themselves. Your child may also vomit and foam at the mouth and their eyes may roll back.

The seizure usually lasts for less than five minutes.

Following a febrile seizure, your child may be sleepy for up to an hour afterwards.

Complex febrile seizures tend to last longer than 15 minutes, and the symptoms may only affect one area of your child's body.

Seeking medical advice

If your child has previously been diagnosed as having febrile seizures, you may not need to seek emergency care. However, it is recommended that you telephone your GP or call NHS 111 for advice.

Also, contact your GP or NHS 111 if your child shows signs and symptoms of dehydration (a lack of fluid in their body). The signs of dehydration are:

  • a dry mouth
  • sunken eyes
  • a lack of tears when crying
  • a sunken fontanelle – this is the soft spot that is usually found at the top of a young child’s head

Emergency advice

You should take your child to the nearest hospital as soon as possible if they have no previous history of seizures and you think they have had one.

Although very rare, a seizure can sometimes be a sign of a more serious illness, such as meningitis, which requires emergency medical treatment.

Dial 999 immediately to request an ambulance if your child has any of the symptoms below:

  • your child is having a seizure that is lasting longer than five minutes and showing no signs of stopping
  • your child has a blotchy red rash that does not fade or change colour when you place a glass against it (such a rash is not always present)
  • your child is having breathing difficulties

Page last reviewed: 01/10/2012

Next review due: 01/10/2014


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