A few factors appear to boost a child's risk of having recurrent febrile seizures, including the following:
- Being younger than 15 months old at the time of the first seizure
- Having frequent fevers
- Having immediate family members with a history of febrile seizures.
If the seizure occurs soon after a fever has begun or when the temperature is relatively low, the risk of recurrence is higher. A long initial febrile seizure does not substantially boost the risk of recurrent febrile seizures, either brief or long.
Although they can be frightening to parents, the vast majority of febrile seizures are harmless. During a seizure, there is a small chance that the child may be injured by falling or may choke from food or saliva in the mouth. Using proper first aid for seizures can help avoid these hazards.
There is no evidence that febrile seizures cause brain damage. Large studies have found that children with febrile seizures have normal school achievement and perform as well on intellectual tests as their siblings who don't have seizures. Even in the rare instances of very prolonged seizures (more than one hour), most children recover completely.
Between 95 and 98 percent of children who have experienced febrile seizures do not go on to develop epilepsy. However, although the absolute risk remains very small, certain children who have febrile seizures face an increased risk of developing epilepsy. Those at greatest risk for epilepsy include:
- Children whose febrile seizures affect only part of the body, are lengthy, or recur within 24 hours
- Children with cerebral palsy (or those exhibiting delayed development or other neurological abnormalities).
Among children who don't have any of these risk factors, only one in 100 develops epilepsy after a febrile seizure.