What is a febrile seizure?

A febrile seizure is a convulsion triggered by fever (typically ≥38°C / 100.4°F) in children aged 6 months to 5 years who have no prior epilepsy, CNS infection, or metabolic abnormality. They are classified as simple (brief, generalized, single episode in 24 hours) or complex (prolonged, focal, or recurrent within 24 hours).

What is the overall recurrence risk?

Without any risk factors, recurrence risk is approximately 12–15%. Each additional risk factor raises this by roughly 20 percentage points. Children with all four major risk factors face a recurrence risk above 70%.

Does a febrile seizure cause epilepsy?

The risk of developing epilepsy after a simple febrile seizure is only slightly above the general population rate (~1–2%). Complex febrile seizures carry a somewhat higher risk but still the majority of children do not develop epilepsy.

Should antipyretics prevent recurrence?

Routine prophylactic antipyretics during febrile illness have not been shown to reliably prevent febrile seizure recurrence in clinical trials. They are used for comfort. This calculator does not constitute treatment advice.

Which children need EEG or imaging?

Simple febrile seizures in children 6 months to 5 years with full recovery generally do not require routine EEG or neuroimaging per AAP guidelines. Complex features, signs of CNS infection, or atypical presentations warrant further workup.

Is this tool a substitute for clinical evaluation?

No. This tool is for educational and clinical decision-support purposes only. All management decisions must be made by a qualified clinician based on the individual patient's full history and examination.

Febrile Seizure Recurrence Risk Calculator

Summary

Select clinical risk factors to estimate the likelihood of febrile seizure recurrence in a pediatric patient.

How it works

Select the child's age at first febrile seizure.
Indicate whether there is a first-degree family history of febrile seizures.
Select the recorded temperature at the time of the seizure.
Indicate whether the seizure had complex features (lasted >15 min, was focal, or recurred within 24 hours).
Indicate whether the child has attended day care or has frequent infections.
The tool sums risk factors and maps the count to a published recurrence risk percentage range.

Use cases

Counsel families after a child's first febrile seizure.
Stratify risk before deciding on prophylactic antipyretic or anticonvulsant management.
Identify children who warrant closer follow-up or neurology referral.
Educate medical students and residents about febrile seizure epidemiology.
Document risk assessment in clinical notes for medicolegal purposes.
Support shared decision-making with parents about recurrence expectations.

Febrile Seizure Risk

Clinical Risk Factors

Recurrence Risk Estimate