Febrile Seizures

Febrile seizures are seizures associated with a fever in young children, usually between about 6 months and 5 years of age. A child may stiffen, shake, or become briefly unresponsive when their temperature rises. Febrile seizures are different from epilepsy, and most brief episodes do not cause lasting harm. They can be frightening to watch, but most children recover fully.

Febrile seizure symptoms usually begin during a rapid temperature rise or while a child has a fever. The seizure may start before anyone realizes the child is ill or measures their temperature. Most episodes affect the whole body, but movements limited to one side, repeated seizures, or a prolonged episode need urgent assessment. Afterward, a child may be sleepy or confused for a short time.

The immediate trigger for a febrile seizure is a fever, often caused by a viral infection and sometimes by a bacterial illness. The precise reason some children have a convulsion febrile response while others do not is not fully understood. A fever does not mean that the seizure itself is caused by an infection in the brain.

Factors That May Contribute

Fever after an infection or, less commonly, after vaccination may occur around the time of an episode; this does not mean vaccines cause epilepsy. A family tendency, combined with the way a young child’s developing brain responds to a rapid temperature change, may increase susceptibility. A febrile seizure in a newborn, a seizure without fever, or a seizure with a stiff neck or other signs of meningitis requires evaluation for causes other than a typical febrile seizure.

Brief, simple febrile seizures generally do not cause intellectual disability or brain damage. Prolonged, focal, recurrent, or otherwise atypical episodes need closer medical assessment because they may carry different risks or point to another cause. Caregivers should follow the child’s safety plan and seek help when warning signs occur.

Clinicians usually diagnose febrile seizures from the event history and a physical examination. Tell them how long the episode lasted, which body parts moved, whether the child responded, whether movements were limited to one side, whether it happened again, the measured temperature, other illness symptoms, and how the child recovered.

When Testing May Be Needed

Blood tests, urine testing, or a lumbar puncture may be considered when an infection or meningitis is suspected. Electroencephalography or brain imaging may be used when the episode is atypical, recurrent, focal, or raises concern about another seizure disorder. These tests are not routine for every simple febrile seizure; the child’s appearance, examination, age, and suspected cause of the fever guide the decision.

Treatment also addresses the underlying illness causing the fever. Offer fluids and use fever-reducing medicine only as directed for comfort; these medicines may help a child feel better but do not reliably prevent another febrile seizure. Avoid cold-water baths or other unsafe cooling methods.

A clinician may prescribe rescue medicine for a prolonged seizure or for a child with repeated or complex episodes. Daily antiseizure medicine is uncommon and is considered individually, based on the child’s history, examination, and overall risk.

There is no guaranteed way to prevent febrile seizures. Routinely checking every fever or aggressively lowering a child’s temperature does not eliminate the risk. Appropriate illness care may support comfort, but fever control cannot reliably stop a seizure.

Most children return to their usual behavior after a brief episode and outgrow febrile seizures as the nervous system matures. A child may be tired or unsettled for a short time afterward, but a simple episode usually does not affect learning or development.

Recurrence is possible, especially during another fever. The later risk of epilepsy remains low overall but is higher when episodes are prolonged, focal, or recurrent, or when developmental or neurologic concerns are present. Your child’s clinician can explain the individual outlook and whether a rescue plan is appropriate.

Arrange follow-up with the child’s clinician after any febrile seizure. The visit can review the source of the fever, the chance of another episode, and whether a rescue plan or additional evaluation is needed.