Port wine stains (capillary vascular malformations)

What are the symptoms of a port wine stain?

A port wine stain looks like a smooth patch of deep pink, red or purple, with a distinct border against the surrounding skin. It's most often found on the face, neck or scalp, though a mark can develop on any part of the body, and usually only affects one side. It's also characterised by:

• A smooth, flat patch that's present from birth
• Colour that can deepen from pink to a darker red or purple as a child grows
• Thickening or small raised bumps and ridges developing later in life, sometimes called a 'cobblestone' texture
• Growth in proportion with the rest of the body
• Occasional small blood blisters (papules), which can bleed easily if they're not treated early.

If the mark is around the eye, on the eyelid, forehead or scalp, or forms a large patch on an arm or leg, mention this to your doctor. These locations are occasionally linked to conditions affecting the eyes, brain or limb growth, covered in the next section.

What causes a port wine stain, and who is at risk?

Researchers have linked port wine stains to a change in a gene called GNAQ, and sometimes a related gene called RASA1. This change happens by chance early in pregnancy, is not inherited from a parent, and is not linked to anything a mother did or did not do while pregnant.

About 3 in 1,000 babies are born with a port wine stain. It cannot be prevented, since it's not linked to anything that happens during pregnancy.

A port wine stain on the upper part of the face is occasionally linked to other conditions affecting the eyes or brain, so your doctor may suggest extra checks if the mark involves:

• The eye or eyelid: A slightly higher chance of glaucoma, a rise in pressure inside the eye that can affect sight if it's not treated
• The forehead or scalp: A small chance of Sturge-Weber syndrome, which can affect blood vessels over the brain and cause seizures
• A large area of an arm or leg: An occasional link to Klippel-Trenaunay syndrome, where the limb grows larger than normal.

These associated conditions are rare and most port wine stains aren't linked to any of them.

Are there different types of port wine stains?

There isn't a formal system of types of port wine stains, though a related mark called a salmon patch (or 'angel's kiss') is sometimes grouped under the same medical term. This appears on the eyelid or between the eyebrows and is seen in around 15% of newborns, but it's a different birthmark from a true port wine stain.

How is a port wine stain diagnosed?

In most cases, your doctor will recognise a port wine stain simply from how it looks, so tests aren't usually needed. In rare cases, a small sample of skin (a biopsy) may be taken to confirm the diagnosis.

If the mark is near the eye, you may be referred to an eye specialist to measure the pressure inside the eye. If it's on the head, a brain scan (an MRI) may be arranged, usually while your baby is under anaesthetic, to check for Sturge-Weber syndrome. Your doctor will also ask about your family's medical history.

How is a port wine stain treated?

A port wine stain often needs no medical treatment at all. Many people still choose treatment for cosmetic reasons, or because of an increased chance of bleeding or thickened skin later in life. There are two main options: a form of laser treatment, or cosmetic camouflage make-up.

Non-surgical treatment

Laser treatment, using a type of laser called a pulsed dye laser, is the option doctors turn to most often to fade a port wine stain. The laser produces a thin, focused beam of light that's absorbed by the red colouring in the blood vessels, producing heat that shrinks or closes them.

1. A test patch is tried first, to see how well your skin responds to the laser
2. A local anaesthetic cream numbs the area beforehand, or, for young children having larger sessions, a general anaesthetic may be used
3. The laser is applied in small 'dots' a few millimetres across, with many dots making up one session
4. A course of 4 to 6 sessions usually takes place over a period of years, spaced roughly 6 to 8 weeks apart
5. Skin looks bruised and feels sore afterwards, similar to a sunburn, and takes around 7 to 10 days to settle.

It is important to note that results vary for laser treatment. Around 70% of children see about a 70% improvement in colour after a course of treatment, though the mark rarely disappears completely. Bright pink or red marks tend to respond better than purple ones, and marks on the face tend to respond better than those on the trunk or legs.

Cosmetic camouflage is a water-resistant, specialist make-up matched to your skin tone. It doesn't remove the mark but covers it for events or everyday wear: on the face it's usually removed each night, while on other parts of the body it can be left on for 3 to 4 days. Once you've learned how to apply it, which usually takes an appointment of up to an hour, it can be prescribed by your GP (family doctor).

Older approaches such as radiation and tattooing were tried in the past but are not recommended today, since laser treatment is safer and more effective.

Surgical treatment

Surgery is not a standard treatment for the birthmark itself. It's sometimes used, alongside laser treatment or a freezing treatment called cryotherapy, to remove the small blood blisters (papules or pyogenic granulomas) mentioned earlier. A specialist surgical team, which may include dermatologists and vascular surgeons, can also be involved if a port wine stain is linked to Klippel-Trenaunay syndrome and its effects on limb growth.

When should I see a doctor?

See your doctor promptly if a port wine stain:

• starts to bleed, especially if the bleeding doesn't stop
• becomes infected, sore, itchy or starts to ooze
• is on or near the eye, eyelid, forehead or scalp, so it can be checked for any effect on the eyes or brain
• is a large mark on an arm or leg, so any effect on limb growth can be monitored.

It's also worth asking a specialist doctor to look at your baby's port wine stain soon after birth, even though treatment itself does not usually begin until later in infancy.