Birthmarks are distinguishing marks that babies are either born with or develop shortly after birth.

By Wallace Health I Medically reviewed by Adrian Roberts.
Page last reviewed: October 2018 I Next review due: October 2021

What are birthmarks?

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.

How to tell if you have birthmarks

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.

Vascular

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:

  • Salmon patch (telangiectatic nevus) — a very common birthmark that doesn't usually need treatment and appears on light and dark skin as thin, flat, pink or red areas, which are caused by the expansion of the tiny blood vessels on your eyelids, back of your neck (stork bites) or face (angel kisses); these patches are more obvious in babies when they cry and usually disappear by age two if they are on the eyelids or forehead but can take longer if they are on the back of the head or neck
  • Strawberry birthmark (infantile haemangioma) — blood vessels that form raised red marks on dark and light skin, appearing shortly after birth on any part of your body, which may need treatment if it affects breathing, feeding or vision; strawberry birthmarks: 
    • Are more common in girls, low birth weight babies, multiple births (eg twins) and premature babies (babies born before 37 weeks)
    • Are most often found on the feet, hands, head or neck
    • Can also occur internally — babies with multiple strawberry birthmarks on their skin should be examined for internal ones
    • Can appear blue  or purple if they occur deeper under the skin
    • Increase in size for the first six to 12 months after birth and usually shrink and disappear by age seven but may leave a pale mark
  • Port-wine stain (capillary malformation) — distinctive flat, dark, purple or red marks present from birth and caused by an abnormal collection of small blood vessels under the skin, which can vary in size and are often on one side of your face, back, chest or neck; port-wine stains: 
    • Can be a sign of an underlying medical condition, such as Klippel-Trenaunay syndrome, macrocephaly-capillary malformation or Sturge-Weber syndrome — these are rare 
    • Can be turned lighter using laser treatment — this is most effective in young children
    • Do not fade or disappear over time and can become darker, lumpier and thicker without treatment 
    • Look very dark on dark skin
    • On eyelids may need treatment 

Pigmented

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:

  • Café au lait mark — a light or dark brown, flat, often oval-shaped patch that is present at birth or appears soon after on any part of your body and doesn’t fade; café au lait marks: 
    • Are common — many children have one or two 
    • Are named because of their colour — café au lait is French for coffee with milk
    • Can be different sizes and shapes 
    • Look darker on dark skin
    • May be a sign of neurofibromatosis type 1 if you have six or more marks
    • May increase in size but often fade
  • Congenital melanocytic naevus — a large, usually round, flat or raised, black or brown mole caused by too many pigment cells in the affected patch of skin, these moles:
    • Can appear on any part of your body and vary in size
    • Can become darker, hairy and raised — this is common during puberty
    • Can fade or last a lifetime
    • Do not usually need treatment unless there is a risk of skin cancer
    • Look darker on dark skin
    • May develop into skin cancer if they are large — the larger the mole, the greater the risk
  • Mongolian spots — blue-grey, bruise-like marks present from birth, which are usually flat and often over the arms, buttocks, legs and lower back; Mongolian spots: 
    • Are also called blue-grey spots
    • Are most common in babies with darker skin
    • Are not a sign of any underlying medical condition
    • Do not need treatment
    • Should be recorded on the baby's medical records
    • Usually fade by age four

Talk to your doctor if you’re concerned about symptoms

You can book an appointment with a Spire private GP today.

Diagnosis and tests for birthmarks

You should see your GP if:

  • You are worried about a birthmark
  • You or your child has a large congenital mole (congenital melanocytic naevus)
  • Your child has six or more cafe-au-lait marks

You should also see your GP if you or your child has a birthmark that: 

  • Has become bigger, darker or lumpier
  • Is close to the eyes, mouth or nose
  • Is painful or sore

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:

  • A mole has recently grown, changed in appearance or is bleeding or itching 
  • Your child’s birthmark is located in a position that may interfere with their breathing, feeding or vision
  • Your child has multiple birthmarks — this may indicate an underlying health condition

Causes of birthmarks

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.

Common treatments for birthmarks

Fortunately, most birthmarks don’t need treatment. This is only necessary if:

  • A birthmark on your face is likely to interfere with breathing, feeding or vision
  • A haemangioma (strawberry birthmark) develops an ulcer or causes internal problems
  • A mole develops skin cancer or shows signs of increased risk of skin cancer

You may also want a birthmark treated because you don’t like the look of it. Birthmark removal options include:

  • Beta-blockers — this includes: 
    • Oral medication that is commonly used to treat high blood pressure but can also help shrink haemangiomas by reducing blood flow and shrinking blood vessels eg propranolol
    • Topical medication to help shrink haemangiomas eg timolol
  • Camouflage make-up — available on prescription, it’s a special type of make-up that can cover birthmarks
  • Corticosteroids — anti-inflammatory tablets or injections that target blood vessels and help shrink haemangiomas
  • Laser therapy — a treatment carried out by a dermatologist or surgeon that involves pulsing beams of light that can lighten or remove port-wine stains over several sessions; treatment can:
    • Be carried out on older children and adults but is usually most effective in young children
    • Be uncomfortable and need a local anaesthetic
    • Cause temporary bruising or swelling
    • Produce permanent results
  • Surgery — recommended for large moles that may be a cancer risk or deep, internal haemangiomas that are causing problems or may damage healthy surrounding tissue; this can involve:
    • surgery carried out under local anaesthetic to cut out the birthmark — if the birthmark is large this may need several surgeries over time to remove sections of it
    • tissue expansion — a surgical procedure to reduce scarring caused by birthmark removal surgery, which involves inserting a balloon under the healthy skin next to the birthmark to encourage new, healthy skin to grow as a flap; when the balloon is removed, the flap of skin can cover the area where the birthmark was

Monitoring birthmarks

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:

  • Becoming more raised or lumpier
  • Darkening in colour
  • Developing irregular borders
  • Increasing in size

Some congenital moles can develop skin cancer. This is rare in children but more common in adults and needs prompt treatment.

Frequently asked questions

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.