What are febrile seizures?

Dr. Jeanne Morrison, PhD
Family Practitioner

Febrile seizures are convulsions brought on by a fever in infants or small children. During a febrile seizure, a child often loses consciousness and shakes, moving limbs on both sides of the body. Less commonly, the child becomes rigid or has twitches in only a portion of the body, such as an arm or a leg, or on the right or the left side only. Most febrile seizures last a minute or two, although some can be as brief as a few seconds, while others may last for more than 15 minutes.

The majority of children with febrile seizures have rectal temperatures greater than 102 degrees F. Most febrile seizures occur during the first day of a child's fever. Children prone to febrile seizures are not considered to have epilepsy, since epilepsy is characterized by recurrent seizures that are not triggered by fever.

This answer is based on source information from the National Institute of Neurological Disorders.

Fever seizures, or "fever fits," are caused by extremely high fevers. Although anyone can have a seizure, seizures are most common in children between the ages of 6 months and 4 years. Fewer than one-half of all children who experience a seizure will experience a second seizure.

Most seizures last only a few seconds to a few minutes and are basically harmless for the child. Seizures lasting longer (more than 30 minutes), however, can be dangerous.

Deborah Mulligan
Deborah Mulligan on behalf of MDLIVE
Your child’s normal body temperature will vary with age, activity, and the time of day. For example, infants are not unlike little humming birds in that their heart beats faster, their respiratory rate is faster and their metabolic rate is faster than the rest of us.  It won't surprise you to learn that infants tend to have higher temperatures than older children.  Everyone’s temperature is highest between late afternoon and early evening and lowest between midnight and early morning.  In some children, fevers can trigger seizures, usually within the first hour of a fever.  A true febrile seizure often runs in families, usually happens in the first few hours of a febrile illness and happens to children between six months and five years of age.  Though it may feel like an eternity to the adult witnessing the convulsion, it usually lasts less than one minute but can last up to a few minutes.   While febrile seizures may be very scary, they are harmless to the child.  Most often, they magically disappear after the child reaches the age of six years.

Young children and infants may be at risk for febrile seizures, which are seizures brought on by a rapid increase in body temperature. They are most common in children younger than 5 years.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.