Birthmarks are very common. Around one baby in three is either born with one or develops one soon afterwards. They affect twice as many girls as boys, vary widely, and may gradually disappear over a few years or stay with you for life, sometimes getting bigger.
Most of the time they’re harmless and not cancerous but occasionally they can signal a specific underlying health problem. They can also cause complications because of where they are, in which case they need to be removed.
You may also want yours removed for cosmetic reasons.
They can appear anywhere, including inside your body. Although there are many different types of birthmarks that look very different from each other, there are two broad categories.
These are abnormal blood vessels under your skin. If they’re pink, red or purple, they’re near the surface. If they’re blue, they’re deeper. Vascular birthmarks can appear anywhere on your body but tend to be more common around your head, face and neck. Common examples include:
These birthmarks are caused by clusters of cells that contain melanin, the skin pigment that makes you tan. They tend to be brown or black but can also be bluish or blue-grey, and may be smooth, flat, raised or wrinkled. These include:
You should see your GP if:
You should also see your GP if you or your child has a birthmark that:
Usually, your doctor can categorise a birthmark by its appearance. But you or your child may be referred to a dermatologist, a doctor who specialises in skin conditions, if:
The exact cause of birthmarks isn’t well understood. Many of them are thought to be due to a change in a gene during the early part of pregnancy when a baby’s skin and blood vessels are forming.
Most birthmarks are not inherited. In rare cases, a birthmark is caused by a change in a specific gene eg some port-wine stains can be a sign of Klippel-Trenaunay syndrome or Sturge-Weber Syndrome, both of which are caused by a genetic mutation. Sturge-Weber Syndrome is not inherited and Klippel-Trenaunay syndrome is not usually inherited.
Marks on your skin that are not present at birth or do not occur shortly after birth, are not birthmarks eg moles that develop with age.
Fortunately, most birthmarks don’t need treatment. This is only necessary if:
You may also want a birthmark treated because you don’t like the look of it. Birthmark removal options include:
Most birthmarks are harmless and many fade or disappear over time. However, you should make sure your GP is aware of your child's birthmarks so they can monitor them and determine if they are a sign of an underlying medical condition that will need treatment.
It is important to monitor your child's birthmarks at home and teach them to monitor their birthmarks as they get older. If you notice rapid changes, you should see your GP. Changes to look out for in birthmarks include:
Some congenital moles can develop skin cancer. This is rare in children but more common in adults and needs prompt treatment.
When should I worry about birthmarks?
If you notice rapid changes in the size, colour, texture or general appearance of your birthmark, you should see your GP eg if it gets bigger, darker or lumpier.
If your child has six or more café au lait marks, you should also see your GP as this could be a sign of an underlying medical condition. Large congenital moles should be monitored by your GP as they carry a risk of developing skin cancer.
Is a birthmark rare?
No, birthmarks are common. One in three babies will be born with a birthmark or develop one soon after. Many children have one or two birthmarks.
Can an ultrasound show birthmarks?
Ultrasound scans are sometimes used after birth to further investigate a birthmark. They can determine how deep a birthmark goes and whether it may affect any other organs.
Do birthmarks get darker in the sun?
Vascular birthmarks eg salmon patches, strawberry birthmarks and port-wine stains do not get darker in the sun. However, pigmented birthmarks eg café au lait marks, congenital melanocytic naevi (congenital moles) and Mongolian spots can darken in the sun.
Do birthmarks change?
Yes, birthmarks can fade and disappear over time but can also get bigger, darker or lumpier. If you notice rapid changes in the size, colour or texture of your birthmark it is important to see your GP. While most birthmarks are harmless some can be a sign of an underlying health condition and large congenital moles carry a risk of developing skin cancer.
How do you lighten a birthmark?
Birthmarks can fade and disappear on their own over time. Treatment to lighten birthmarks depends on what type of birthmark you have. Laser therapy can lighten or remove port-wine stains and involves pulsing beams of light at the birthmark over several sessions. This is most effective in young children but can also be carried out on older children and adults.
Some birthmarks can’t be lightened. However, if you don’t like the look of your birthmark, you can see your doctor about your treatment options for removal, which include medication and surgery.