Encyclopedia Home / F / Febrile seizures

Febrile seizures

  • Definition

    A febrile seizure is a convulsion in a child triggered by a fever. These convulsions occur without any brain or spinal cord infection or other nervous system (neurologic) cause.


    Alternative Names

    Seizure - fever induced


    Causes, incidence, and risk factors

    About 3 - 5% of otherwise healthy children between ages 9 months and 5 years will have a seizure caused by a fever. Toddlers are most commonly affected. Febrile seizures often run in families.

    Most febrile seizures occur in the first 24 hours of an illness, and not necessarily when the fever is highest. The seizure is often the first sign of a fever or illness

    Febrile seizures are usually triggered by fevers from:

    • Ear infections
    • Roseola infantum (a condition with fever and rash caused by several different viruses)
    • Upper respiratory infections caused by a virus

    Meningitis causes less than 0.1% of febrile seizures but should always be considered, especially in children less than 1 year old, or those who still look ill when the fever comes down.

    A child is likely to have more than one febrile seizure if:

    • There is a family history of febrile seizures
    • The first seizure happened before age 12 months
    • The seizure occurred with a fever below 102 degrees Fahrenheit