Seizure associated with fever in infants and children 6 months to 6 years of age, not due to metabolic disturbance, central nervous system (CNS) lesion, or CNS infection, and where there does not exist a prior history of afebrile seizures. Simple febrile seizures are characterized by temperature of 100.4°F or higher and involve a single seizure lasting under 15 minutes. Complex febrile seizures, which are less common, are characterized by seizures of greater than 30 minutes or recurrence of the seizures within 24 hours. Other more serious causes of seizure must be ruled out if the neurologic exam is abnormal or if signs and symptoms of CNS infection or systemic illness exist.