Causes of Febrile Seizures
The causes of febrile seizures are linked to the rapid rise in body temperature during infections. These seizures are not caused by epilepsy, brain injury, or low blood sugar, but by a developing nervous system’s response to fever. They are more about how the child’s brain reacts to temperature changes than the illness itself.
Infections Triggering Fever
Common illnesses that can trigger febrile seizures include:
Viral infections, such as influenza, roseola, and adenovirus
Bacterial infections, like tonsillitis, ear infections, and pneumonia
Childhood illnesses, such as measles or chickenpox
Post-vaccination fever, occasionally seen after immunisations like MMR (measles, mumps, rubella)
It’s important to note that febrile seizures are not caused by the vaccine itself but by the fever that may follow as a natural immune response.
Fever Response in Young Children
Young children have immature thermoregulatory and nervous systems. When their temperature rises quickly—particularly over 38.5°C (101.3°F)—the brain may respond with a seizure. This is more likely during the first day of fever.
Factors increasing seizure risk:
Rapid temperature rise, rather than the highest temperature reached
First-time fevers, especially in infants
Sleep or drowsiness, as seizures are more likely when the brain is already in a relaxed state
Genetic Predisposition
There is a strong hereditary element:
A child is more likely to have febrile seizures if a parent or sibling had them
Some families may carry genes that make children more sensitive to fever spikes
However, most children with febrile seizures do not go on to develop epilepsy
Not Caused By
Febrile seizures are not caused by:
Head injuries
Low blood sugar
Teething
Poor parenting or neglect
Epileptic disorders (though the distinction can require assessment)
Causes of Febrile Seizures
Understanding the causes of febrile seizures reassures parents that they are not due to anything they’ve done wrong and helps reduce unnecessary worry during future fevers.
[Next: Symptoms of Febrile Seizures →]
