Febrile seizures (seizures caused by fever in young children) are dangerous and cause permanent brain damage.
Most febrile seizures are benign and self-limited, lasting less than 15 minutes. Long-term neurological consequences are rare. Febrile seizures do not cause brain damage or increase the risk of epilepsy significantly in most cases. While frightening for parents, febrile seizures are a common occurrence in childhood (affecting 3-4% of children) and generally don't require long-term anticonvulsant medication.