Birthmarks are coloured marks that are visible on the skin. They are often present at birth or develop soon afterwards.

There are several different types of birthmark and some of them are very common.

The two main types of birthmark are:

• vascular birthmarks (often red, pink or purple) caused by abnormal blood vessels in or under the skin
• pigmented birthmarks (usually brown) caused by clusters of pigment cells

Vascular birthmarks usually occur in the head and neck area, mainly on the face. However, both types of birthmark can appear anywhere, including inside the body.

If surface blood vessels are affected, a vascular birthmark will appear red, purple or pink. If the affected vessels are deep, the birthmark will appear blue.

Pigmented birthmarks are tan or brown coloured skin marks.

Vascular birthmarks

Some of the most common types of vascular birthmarks are described below.

• Salmon patch (stork mark) - red or pink flat patches that can appear on a baby's eyelids, neck or forehead at birth. They are the most common type of vascular birthmark and occur in around half of all babies. Most will fade away within a few months but salmon patches on the forehead may take up to four years to disappear. Patches on the back of the neck often last. They are often more noticeable when a baby cries.
• Infantile haemangioma - a raised mark on the skin that is usually red and can appear anywhere on the body. These are also known as strawberry marks. Sometimes, they are deeper in the skin, in which case the skin can look blue or purple. Haemangiomas are also common, especially in girls, and affect around 5% of babies soon after birth. They increase in size rapidly for the first six months but will eventually shrink and disappear by around seven years of age. Very bulky haemangiomas, those that rapidly increase in size and those that get in the way of vision or feeding may need treatment. 
• Port wine stain - red or purple flat marks that affect around 0.3% of newborn babies. They can vary in size, from a few millimetres to several centimetres in diameter. Port wine stains often occur on one side of the body and usually appear on the face, chest and back, although they can appear anywhere. Port wine stains tend to be sensitive to hormones and may become more noticeable around puberty, pregnancy and the menopause. Most are permanent and may deepen in colour over time.

Pigmented birthmarks

Some of the most common types of pigmented birthmarks are described below.

• Café-au-lait spots - coffee-coloured skin patches. Many children have one or two of these, but if more than six have developed by the time the child is five, see your GP as it could be a sign of neurofibromatosis.
• Mongolian spots - blue-grey or bruised-looking birthmarks which are present at birth. They are more commonly seen in darker-skinned people and usually appear over the lower back or buttocks, but can also appear elsewhere on the body or limbs. They may last for months or years, but usually disappear by the age of four. They are completely harmless and do not need treatment. They may be mistaken for a bruise.
• Congenital melanocytic naevi (CMN) - also known as congenital moles. These are relatively large brown or black moles that are present at birth. They are fairly common and are caused by an overgrowth of pigment cells in the skin. Most CMN become proportionally smaller and less obvious with time, although they may darken during puberty or become bumpy or hairy. They can range in size from less than 1.5cm to more than 20cm in diameter. The risk of CMN developing into skin cancer is low, but this risk increases with the size of the CMN.

What causes birthmarks?

It is not understood exactly why birthmarks occur, but they are not usually inherited. Vascular birthmarks are caused by abnormal blood vessels in or under the skin, while pigmented birthmarks are caused by clusters of pigment cells.

It is thought that port wine stains occur because the nerves that control the widening or narrowing of the capillaries (tiny blood vessels) do not function properly, or there are not enough of them. This means that blood is constantly supplied to the skin in that area, which makes it permanently red or purple in colour.

Port wine stains are sometimes related to other conditions, such as Sturge-Weber syndrome and Klippel-Trenaunay syndrome. Read more about the complications associated with birthmarks.

Is treatment needed for birthmarks?

Most birthmarks are harmless and do not need to be treated. Some types of birthmark will fade over time whereas other types, such as port wine stains, are permanent if they are not treated. In some cases, a birthmark will need to be treated for medical reasons, for example if a haemangioma blocks the airways, affects vision or becomes ulcerated. Some people may seek treatment for cosmetic reasons.

Read more about treating birthmarks.

Most birthmarks are harmless and some disappear without treatment. However, some types of birthmark may need treatment for medical reasons and some people may choose to have them treated for cosmetic reasons.

Haemangiomas

Some haemangiomas will disappear without treatment but they often don't change until your child is two years old. Around half will have gone by the age of five, and some haemangiomas may last until your child is 12 years old.

In cases where a haemangioma has left the skin deformed or stretched, plastic surgery may be an option to improve the appearance of the distorted skin.

If the haemangioma has formed an ulcer, you may need to take extra measures to prevent infection, and surgery or laser treatment may be offered (see below). Read more information about the complications of birthmarks.

Complicated or large haemangiomas

Some haemangiomas may cause complications that will need treatment.

A haemangioma near your child's eye, nose or mouth may cause problems with vision, breathing and feeding. Haemangiomas on the lip or around the nappy area are more likely to form ulcers, which sometimes bleed and can be painful.

The exact treatment will depend on where and how severe the haemangioma is. Most haemangiomas can be effectively treated with medicine, for example oral propranolol (see below) in liquid form. This will shrink the birthmark. If propranolol is not working, other medicines can occasionally be used, such as steroids or vincristine. Surgery is rarely necessary.

If your child has breathing difficulties because of a haemangioma in the airway, they may need laser treatment during an examination of their airway using a small telescope, known as an endoscope. This is known as microlaryngoscopy and bronchoscopy or MLB. They may also be given propranolol.

Occasionally, a child with an airway haemangioma may need to have a temporary tracheostomy (artificial opening into the windpipe) to improve their breathing.

Propranolol

If the haemangioma is complicated or large, your child may be offered medication. This is usually a beta-blocker called propranolol. The full side effects of using this medicine to treat a haemangioma are still being monitored.

Beta-blockers work by blocking the release of noradrenaline in certain parts of the body. Noradrenaline is a chemical released by nerves when they are stimulated. The noradrenaline passes messages to other parts of the body, such as the muscles, blood vessels and heart.

It is thought that propranolol helps narrow the blood vessels, reducing the amount of blood running through them. This reduces the colour and makes them softer. The cells that cause the growth of the haemangioma are also affected so the haemangioma gets smaller.

Monitoring internal haemangiomas

If a haemangioma is present in your child's internal organs, they may need an ultrasound scan or magnetic resonance imaging (MRI) scan to confirm its location and size. An MRI scan uses a strong magnetic field and radio waves to produce detailed pictures of the inside of the body.

Port wine stains

Port wine stains are permanent. However, some treatments help the mark to fade, making it less noticeable, or you can disguise it with cosmetics.

Laser treatment

Laser treatment lightens the affected area of skin, and it is the only treatment for a port wine stain. Laser treatment often works better in younger children as a port wine stain may have become bumpy and raised after an adult has had one for a number of years.

The most common laser treatment is known as pulsed dye laser treatment. The laser passes through a fibre optic cable. On the end of the cable is a device that looks like a pen. This is held gently against the surface of your child's skin, and a button is pressed, which sends a beam of light to the skin.

The light goes less than 1mm into the skin. It is absorbed by the blood vessel just beneath the surface, which causes it to heat up. The heat damages the blood vessel, which creates a bruise, but this will fade within a week or two.

During or after treatment, your child's skin is cooled to reduce discomfort, or a jet of cold air might be blown onto the skin during treatment.

Some possible side effects of laser treatment include:

• Bruising - after some types of laser treatment, it is normal for the mark on the skin to look worse because of bruising. The bruising will fade over the next one to two weeks.
• Pain - the laser stings so most children have laser treatment under general anaesthetic (where they are put to sleep). Some children can tolerate treatment with the help of a local anaesthetic cream that numbs the skin. Children having laser treatment using only the numbing cream will sometimes have a cold gel pad put on the area before treatment to help with discomfort.
• Increased sensitivity to sunlight - your child's skin is very prone to sunburn for up to six months after laser treatment.

Between 3 and 30 treatment sessions may be needed at intervals of six to eight weeks.

How effective the treatment is will depend on how prominent and dark the affected area is. The best results are often seen in marks that are already smaller and lighter.

Camouflage make-up

You can get a prescription for a special type of camouflage make-up, which will cover up the birthmark.

The charity Changing Faces now runs the skin camouflage service previously run by the Red Cross. You can book an appointment with a trained volunteer who can teach you to apply the make-up.

You can read more information about skin camouflage from the British Association of Skin Camouflage and the Skin Camouflage Network.

Congenital melanocytic naevi (CMN)

As CMN can affect a person's appearance, surgery may be considered. However, this will leave scarring and may not be possible if the affected area is very large.

Surgery involves removing the affected birthmark and stitching together the edges of the skin. If the area is large, a skin graft may be required. A skin graft involves taking skin from another place and using it to cover the wound. Read more information about how a skin graft is performed.

Most birthmarks are harmless. However, in rare cases there can be complications which need to be treated.

Haemangiomas

Although it is rare, some haemangiomas can cause severe problems or can even be life threatening. They may interfere with eating, breathing or eyesight, so they need to be treated. Read more information about treating birthmarks .

If your child has a haemangioma near their eye, nose, mouth or nappy area, they may need to be referred to a specialist.

Some haemangiomas may bleed or become infected. If the birthmark bleeds, apply pressure to it until the bleeding stops.

See your GP if your child's haemangioma forms an ulcer, because it can become infected and may be very painful. Keep the wound clean and covered with a dressing. It should heal within two weeks. Infected haemangiomas need urgent treatment with antibiotics because they are very painful, and the infected ulcer may leave an unsightly scar.

If your child has more than five haemangiomas, it may be a sign that they have internal haemangiomas. It is very unusual for these to cause any problems, but an ultrasound scan or magnetic resonance imaging (MRI) scan may be carried out to see if any internal haemangiomas are present.

Most internal haemangiomas cause no symptoms. Very rarely, they might cause:

• coughing and difficulty breathing, which may indicate airway haemangiomas
• blood in the stools, which may indicate haemangiomas in the bowel

Port wine stains

Port wine stains can lead to the following complications: 

• Glaucoma (raised pressure within the eye, which affects vision) - you may have this condition if the birthmark affects both the upper and lower eyelids on the same side.
• Sturge-Weber syndrome - a rare disorder that affects the eyes and brain. It is usually associated with a large port wine stain, which extends across the forehead or scalp. See the National Institute of Neurological Disorders and Stroke (NINDS) website for more information about Sturge-Weber syndrome.
• Soft tissue hypertrophy (the tissue beneath the birthmark enlarging) - this may occur on a lip, for example.
• Klippel-Trenaunay syndrome - a rare disorder present at birth, where the blood vessels fail to form properly. If your child has a port wine stain on their limb and this is enlarged, they may have Klippel-Trenaunay syndrome. See the NINDS website for more information about Klippel-Trenaunay syndrome.

Any of these conditions will need to be treated by a specialist.

Congenital melanocytic naevi (CMN)

If your CMN increases in size or changes shape or colour, your doctor may suggest a biopsy (where a tissue sample is taken for closer examination). See your doctor if you notice any of the following changes in your congenital melanocytic naevi (CMN):

• bleeding
• colour change
• inflammation (swelling)
• itching
• open sore
• pain
• size change
• texture change

Although it is very rare, some CMN can develop into skin cancer. This risk increases with the size of the CMN. Read more information about moles.