Febrile seizures - 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 38C (100.4F) or above. 

However, there appears to be no connection between the extent of your child’s fever and the start of a seizure. Seizures can occur even if your child has a mild fever.

Simple febrile seizures can happen when there's a rapid rise in temperature and you may only realise your child is ill when they have a fit. Alternatively, they can occur as your child’s temperature drops from a high level.

During simple febrile seizures:

• your child’s body will become stiff and their arms and legs will begin to twitch
• they'll lose consciousness and they may wet or soil themselves
• they may also vomit and foam at the mouth and their eyes may roll back
• the seizure usually lasts for less than five minutes
• following the 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. The seizure sometimes recurs within 24 hours or during the period in which your child is ill.

Seeking medical advice

You should take your child to hospital or dial 999 for an ambulance if:

• your child is having a fit for the first time
• the seizure lasts longer than five minutes and shows no signs of stopping
• you suspect the seizure is being caused by another serious illness, for example meningitis
• your child is having breathing difficulties

If your child has previously had febrile seizures, it's recommended that you telephone your GP or call NHS 111 for advice.

You should also contact your GP or NHS 111 if your child shows signs and symptoms of dehydration (a lack of fluid in the body). This includes:

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