A temperature of 100.4°F (38°C) or above may cause febrile seizures in children.

A febrile seizure can be frightening for any parent or caregiver. Most of the time, a febrile seizure does not cause any harm. The child usually does not have a more serious long-term health problem.

Febrile seizures occur most often in otherwise healthy children between ages 6 months and 5 years. Toddlers are most commonly affected. Febrile seizures often run in families.

Most febrile seizures occur in the first 24 hours of an illness. It may not occur when the fever is highest. A cold or viral illness may trigger a febrile seizure.