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Sturge-Weber syndrome

Sturge-Weber syndrome (SWS) is a rare condition, in which the presence of a birthmark (called a ‘port wine’ stain), usually on one side of the face but sometimes both sides, is associated with an abnormality of the brain. This is caused by abnormal blood vessels on the surface of the brain. This abnormality usually results in epileptic seizures and other problems.

The abnormal blood vessels are usually over the back part of the brain (the occipital lobe). They may also be in other regions of the brain and, rarely, on both sides of the brain. The abnormality develops during pregnancy, probably in the first 3 to 4 months.

SWS is usually a spasmodic occurrence – meaning it does not run in families. It is very, very rare for two children in the same family to have SWS.


The first abnormality noted in SWS is usually the birth mark. This is flat and deep red. It is due to abnormalities of the very small blood vessels in the skin. The medical word for this abnormality is ‘angioma’. The birth mark is usually on the forehead on one side of the face, often coming down on to the cheek, nose or upper lip. Rarely, both sides of the face are involved and, on occasions, similar birth marks are present on other parts of the body. Even more rarely the birth mark may not be visible.

Two out of every 3 children with SWS will have seizures. They may start at birth or in the first year of life. They are usually focal (also called partial) motor seizures involving jerks of one side of the body only. The seizures may become generalised and evolve into other types of seizures, such as atonic seizures ‘drop attacks’, myoclonic seizures or infantile spasms.

The seizures are often very frequent and prolonged seizures may happen. This may result in status epilepticus. Tonic-clonic seizures lasting more than 5 minutes need urgent treatment. This is to try and stop them before they cause long-term damage.  If a tonic-clonic seizure or cluster of tonic-clonic seizures lasts for 30 minutes or more it can cause damage to the brain, or even death. Both focal and generalised seizures can turn into status epilepticus.  

After frequent or prolonged seizures, a weakness in one side of the body (hemiparesis or hemiplegia) frequently develops. The severity of weakness is closely related to the frequency and severity of the seizures.

As the child grows the weakness may become more severe and permanent. Often, abnormalities of vision develop, with an inability to see on the same side as the weakness (hemianopia).

The abnormal blood vessels may also involve the eye directly and result in an abnormality of the drainage of fluid within the eye. This results in raised pressure in the eye (glaucoma). This may be present at birth and may cause visual impairment if not treated.

Learning disabilities are present in up to 2 out of 3 children with SWS. In some children, severe learning disabilities develop. The more frequent and the more severe the seizures, the greater is the severity of the learning disabilities.


The diagnosis of SWS is usually relatively easy. This is because of the characteristic ‘port-wine’ birth mark on one side of the face and neck is seen at or soon after birth. However, sometimes the diagnosis is more difficult. This is when the birth mark is very pale or occurs only over the scalp and is covered by the child’s hair. A computerised tomography (CT) brain scan will usually show the typical abnormalities of the blood vessels on the surface of the brain better than a magnetic resonance imaging (MRI) brain scan.


Treatment is mainly directed towards trying to control the frequent seizures. This is because the outcome depends very much on controlling the seizures. This may be possible with epilepsy medicines. However, in many cases the epilepsy is resistant to medical treatment. In these cases, early consideration should be given to epilepsy brain surgery. The surgery involves disconnecting part of the brain in the region of the abnormal blood vessels. This is called a ‘hemispherotomy’, and is the type of surgery used most in SWS. Sometimes the whole of the hemisphere is actually removed; this is called a ‘hemispherectomy’. The outcome from surgery may be excellent.

Treatment of glaucoma, if it develops, is possible and laser treatment may be very effective for the birth marks.

Information about treatments for children can be found on the Medicines for Children website.

There may be research studies open that are relevant to this epilepsy syndrome. Your child’s hospital doctor (paediatrician or paediatric neurologist) will be able to discuss this with you.

Your child may have prolonged or repeated seizures as part of SWS. Your child’s hospital doctor paediatrician or paediatric neurologist) will discuss a ‘rescue’ or emergency care plan with you to treat any prolonged or repeated seizures.


SWS is a slowly progressive condition. This is because the abnormal blood vessels affect the blood supply to the brain. As the person gets older, the blood flow to the brain through the abnormal blood vessels lessens and causes further damage. This means that the weakness down one side of the body worsens and the seizures become more frequent. The outlook depends on how much of the brain is affected. This seems to be closely linked with the frequency and the severity of the seizures.

If the seizures are frequent, prolonged and difficult to control then the learning difficulties, hemiplegia and visual problems will usually be more severe. If the seizures are controlled, then a much better (but not necessarily normal) outlook can be expected.

If the abnormality is present on both sides of the brain the outcome is usually poor because the seizures are more severe and the learning disabilities are greater. In addition, it is less likely that surgery (hemispherotomy or hemispherectomy) will cure the epilepsy.


209-211 City Road
London EC1V 1JN
Phone: 0808 808 3555
Website: www.cafamily.org.uk

Sturge-Weber Foundation (UK)
348 Pinhoe Road
Exeter EX4 8AF
Phone: 01392 464 675
Website: www.sturgeweber.org.uk 

HemiHelp is a charity providing support and information to people with hemiplegia and their families in the UK.
Website: hemihelp.org.uk 

What is a syndrome?

A syndrome is a group of signs and symptoms that, added together, suggest a particular medical condition. In epilepsy, examples of these signs and symptoms would be things like the age at which seizures begin, the type of seizures, whether the child is male or female and whether they have physical or learning disabilities, or both. The results of an EEG are also used to help identify epilepsy syndromes.

If you would like to know more about an epilepsy syndrome, please speak to your doctor. If you would like to know more about epilepsy in general, please contact Epilepsy Action.


Our thanks

Epilepsy Action would like to thank Dr Richard Appleton, consultant paediatric neurologist at Alder Hey Children’s Hospital, Liverpool, UK for preparing this information.

This information is exempt under the terms of The Information Standard.

  • Updated November 2016
    To be reviewed November 2019

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