Febrile seizures are seizures or convulsions that occur in young children. They are triggered by fever typically above 101 degrees Fahrenheit (38.3 degrees Celsius). Seizures may happen during illnesses such as a cold, the flu, or an ear infection. In some cases, a child may not have a fever at the time of the seizure but will develop one a few hours later.

Having a febrile seizure does not mean a child has epilepsy. Epilepsy involves repeat seizures that are not triggered by fever.

About one in every 25 children will have at least one febrile seizure. Young children between the ages of about 6 months and 5 years old are the most likely to have febrile seizures. Children are at the greatest risk of having a febrile seizure at age 2. The older a child is when the first febrile seizure occurs, the less likely that child is to have more as there will be less time spent in the age group at risk.

About 40 percent of children who have one febrile seizure will have another. Certain things increase the risk for more febrile seizures, including:

• Young age—Children who have their first febrile seizure when they are younger than 18 months are at an increased risk of having another one.
• Family history—Children whose family members had febrile seizures are more likely to have more than one seizure.
• First sign of illness—Children who have febrile seizures before exhibiting other symptoms of an illness are at greater risk of having multiple seizures.
• Low temperature—Children are more likely to have another febrile seizure if the first one was accompanied by a relatively low temperature.

Symptoms may include:

• Loss of consciousness or passing out
• Uncontrollable shaking
• Eye rolling
• Rigid (stiff) limbs

Less commonly, a child can become rigid or have twitches in only part of the body.

Most febrile seizures last a minute or two. Yet some may only last a few seconds and others may last for more than 15 minutes.

Febrile seizures that last less than 15 minutes do not cause any long-term health problems. However, if another one happens, it is more likely to be prolonged or longer than 15 minutes. A first febrile seizure that is prolonged does not boost the risk of having more. Even prolonged seizures are generally harmless on their own, but they do carry an increased risk of developing epilepsy.

To diagnose febrile seizures in infants and children, healthcare providers will review a child's medical history and perform a physical exam. They often test blood and urine to help pinpoint the cause of the fever. Keep in mind that dehydration from severe diarrhea or vomiting can cause seizures.

Meningitis, an infection of the membranes surrounding the brain, can cause both fever and seizures that can look like febrile seizures but are much more serious. If meningitis is suspected, health care providers may remove and test a small amount of the fluid that surrounds the brain and spinal cord.

Most of the time, children who have febrile seizures will not need to be in the hospital. Healthcare providers may recommend hospitalization if:

• The seizure is prolonged
• The child has a serious infection
• The child is younger than 6 months of age

Parents and caregivers should remain calm, take first aid measures, and carefully watch the child. During a febrile seizure, parents and caregivers should:

• Note the start time of the seizure. If it lasts longer than five minutes, call an ambulance. The child should be taken right away to the nearest medical facility.
• Call an ambulance if the seizure is less than five minutes but the child does not seem to be recovering quickly.
• Gradually place the child on a protected surface such as the floor to prevent injury. Do not restrain or hold a child during a convulsion.
• Put the child on his or her side or stomach to prevent choking. When possible, gently remove any objects from the child's mouth. Nothing should ever be placed in the child's mouth during a seizure. These objects can block airway and make it hard to breathe.
• Seek immediate medical attention if this is the child's first febrile seizure. Once it is over, take the child to the doctor to check for the cause of the fever. This is especially urgent if the child shows these symptoms of meningitis, an infection over the brain surface, which can include stiff neck, extreme lethargy, or a lot of vomiting.

Drugs that lower fevers such as acetaminophen or ibuprofen may provide comfort yet studies show that treating a fever does not lower the risk of febrile seizure. Healthcare providers may recommend other medications to control seizures if needed.

What is a febrile seizure?

Sometimes, fevers can cause a child to experience spasms or jerky movements called seizures. Seizures caused by fever are called “febrile seizures.” They are most common with fevers of 102°F (38.9°C) or higher, but they can also happen at lower body temperatures or when a fever is going down. Most febrile seizures last for less than one or two minutes.

Febrile seizures can be frightening, but nearly all children who have a febrile seizure recover quickly. Febrile seizures do not cause any permanent harm and do not have any lasting effects.

Febrile seizures can happen with any condition that causes a fever.

Fevers can be caused by common childhood illnesses like colds, the flu, an ear infection, or roseola. Vaccines can sometimes cause fevers, but febrile seizures are uncommon after vaccination.

Infants and young children are most at risk for febrile seizures.

Up to 5% of young children will have a febrile seizure at some time in their life. Febrile seizures happen in children between the ages of 6 months and 5 years, with most occurring between 14–18 months of age. About 1 out of every 3 children who have a febrile seizure will have at least one more during childhood. There is a small increased risk for febrile seizures after MMR and MMRV vaccines.

Studies have shown a small increased risk for febrile seizures during the 5 to 12 days after a child has received their first vaccination with the measles, mumps, rubella (MMR) vaccine. The risk is slightly higher with the measles, mumps, rubella, varicella (MMRV) combination vaccine, but the risk is still small. Studies have not shown an increased risk for febrile seizures after the separate varicella (chickenpox) vaccine.

There is a small increased risk for febrile seizures when inactivated influenza vaccine (flu shot) is given at the same doctor visit as either the PCV13 (pneumococcal) vaccine or the DTaP vaccine.

A CDC study of children aged 6 months to 2 years has shown a small increased risk for febrile seizures during the 24 hours after a child receives the inactivated influenza vaccine (flu shot) at the same time as the pneumococcal 13-valent conjugate (PCV13) vaccine or the diphtheria, tetanus, acellular pertussis (DTaP) vaccine. The flu shot was not associated with an increased risk of febrile seizures when it was given on a different day from the other two vaccines. Studies have not shown an increased risk for febrile seizures after the DTaP vaccine, except when it is given at the same time as the flu shot. There may be a small increase in the risk of febrile seizure when PCV13 (pneumococcal) vaccine is given by itself.

The risk of febrile seizure with any combination of these vaccines is small (at most 30 febrile seizures in 100,000 children vaccinated) and CDC’s Advisory Committee on Immunization Practices (ACIP) continues to encourage the vaccination of children according to the vaccination schedule, which allows for the flu, pneumococcal and DTaP vaccinations to be given during the same doctor’s visit.

Vaccines can also help prevent febrile seizures.

Vaccinating children at the recommended age may prevent some febrile seizures by protecting children against measles, mumps, rubella, chickenpox, influenza, pneumococcal infections and other diseases that can cause fever and febrile seizures.