What is an absence seizure?

An absence seizure is a kind of seizure that affects your whole brain at the same time. This kind of seizure usually begins in childhood but can also happen in teens and adults. Absence seizures start suddenly and make you stop what you are doing and stare into space. People may think you are daydreaming or not paying attention.

Absence seizures can happen many times a day. Each one lasts between 5 to 30 seconds. They mostly affect children and young people and can cause problems with learning, so it's important to get treatment.

Absence seizures used to be called 'petit mal' seizures. They are a type of epilepsy, a condition that affects the electrical activity in the brain, causing the seizure.

What are the symptoms of an absence seizure?

In a typical absence seizure, you suddenly stop what you are doing and lose awareness.

Here are some typical symptoms of an absence seizure:

• You will stop what you're doing and lose consciousness.
• You may stare vacantly, without any facial expression.
• You likely won’t react if someone tries to talk to you or get your attention.
• Your eyes may blink and you may have upward eye movements.
• You may make mouthing or chewing movements.
• Your hands may move slightly.

The seizure will usually last for 5 to 30 seconds, pass quickly, and start and end suddenly. After the seizure your awareness quickly goes back to normal.

There are some less common types of absence seizure with different symptoms:

• Atypical absence seizures — these can be slower to start and stop, and the person may slump or fall.
• Myoclonic absence seizures — where the person rhythmically jerks their shoulders or arms or twitches their face.
• Absence seizures with eyelid myoclonia — where the eyelids jerk and the eyes roll upwards.

What are the warning signs of an absence seizure?

Warning signs that a seizure is on its way can be different for everyone. Some people may have no warning. Before a seizure you may have:

• mood changes
• anxiety
• lightheadedness
• trouble sleeping
• trouble staying focused
• changes in behaviour

When should I call an ambulance or go to the emergency department?

See your doctor or visit the emergency department if you're not sure if you or your child has had a seizure.

You should also visit the doctor if you or your child:

• has a seizure but has not had one before
• are having more seizures than normal
• continue having seizures while taking medicines for seizures
• are injured after having a seizure

When should I call an ambulance?

Dial triple zero (000) and ask for an ambulance for your child if:

• you think it is the child's first seizure
• the seizure lasts more than five minutes
• your child remains unconscious or has trouble breathing after the seizure
• your child is having a seizure in water
• your child has an injury after their seizure
• you’re not sure if your child is recovering normally

The operator will tell you what to do while you wait for the ambulance. You should stay with the person and prevent them from injuring themselves during a seizure.

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What causes an absence seizure?

The exact cause of absence seizures is not known right now. Genetic factors or changes in how signals move through neurons (brain cells) might be involved in absence seizures.

How is an absence seizure diagnosed?

Talk to your doctor if you think you or your child might be having absence seizures. Your doctor will ask you questions and examine you. A paediatrician (child specialist) or neurologist (brain and nerve specialist) will likely need to be involved in your care.

They will refer you for tests, including an electroencephalogram (EEG), to measure the electrical activity in your brain. Doctors look for a certain brain wave pattern to help diagnose absence seizures. They may also refer you for other scans and blood tests.

If you live with someone who you think has absence seizures, try to record the seizure happening. Seeing exactly what happens during the seizure can help a doctor to make the correct diagnosis.

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How is an absence seizure treated?

Medicines can usually stop absence seizures. Some children will stop having absence seizures as teenagers and won’t need medicine anymore.

There are many different medicines used to treat seizures. To search medicines by active ingredient or brand name, use the healthdirect Medicines search feature.

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How can absence seizures be prevented?

If you have absence seizures, you can't always prevent them from happening. You can try to avoid things that might trigger your seizures. Triggers can include:

• not taking your medicines
• flashing lights
• being very tired or sleep deprived
• hyperventilation (shallow fast breathing)
• being stressed
• not eating regular meals
• drinking alcohol or taking illegal drugs

Some people follow special diets to help manage their seizures. Ask your paediatrician or neurologist if there is a diet that might help your type of seizures.

Always keep an eye on your child with absence seizures when they are swimming, in the bath or up high. Your doctor can give you more information about how to keep your child safe.

Resources and support

For more information about epilepsy, visit Epilepsy Australia or call their national helpline on 1300 852 853.

For information and support, visit Epilepsy Action Australia or call 1300 37 45 37.

The Royal Children's Hospital Melbourne has helpful information about keeping children who have had seizures safe.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.