Birthmarks are coloured marks that are visible on the skin. They're 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 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.
Some of the most common types of vascular birthmarks are described below.
Salmon patch (stork mark)
Salmon patches are red or pink flat patches that can appear on a baby's eyelids, neck or forehead at birth.
They're the most common type of vascular birthmark and occur in around half of all babies.
Most salmon patches will fade completely within a few months, but if they occur on the forehead they may take up to four years to disappear.
Patches on the back of the neck can last longer. They're often more noticeable when a baby cries.
Infantile haemangiomas are raised marks on the skin that are usually red. They can appear anywhere on the body. They're also known as strawberry marks.
Sometimes infantile haemangiomas occur deeper in the skin, in which case the skin can look blue or purple.
Haemangiomas are common, particularly in girls, and affect around 5% of babies soon after birth. They rapidly increase in size for the first six months before eventually shrinking and disappearing by around seven years of age.
Haemangiomas that get bigger rapidly or those that get in the way of vision or feeding may need to be treated.
Port wine stain
Port wine stains are flat red or purple marks that affect a very small number of newborn babies. They can vary in size, from a few millimetres to several centimetres in diameter.
Port wine stains often affect one side of the body and usually occur on the face, chest and back (although they can occur anywhere).
Some of the most common types of pigmented birthmarks are described below.
Café-au-lait spots are coffee-coloured skin patches. Many children have one or two, but if more than six have developed by the time the child is five, you should see your GP. This could be a sign of neurofibromatosis (a number of genetic conditions that cause tumours to grow along your nerves).
Mongolian spots are blue-grey or bruised-looking birthmarks that are present from birth.
They're more commonly seen in darker-skinned people and usually occur over the lower back or buttocks. However, they can also appear elsewhere on the body or limbs.
Mongolian spots may last for months or years, but they usually disappear by the time a child reaches four years of age. They're completely harmless and don't need treatment. They may sometimes be mistaken for a bruise.
Congenital melanocytic naevi
Congenital melanocytic naevi are also known as congenital moles. They are relatively large brown or black moles that are present from birth.
They're fairly common and are caused by an overgrowth of pigment cells in the skin. Most congenital melanocytic naevi 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 (about 0.6 inches) to more than 20cm (about 7.9 inches) in diameter. The risk of a naevi developing into skin cancer is low, but the risk increases the larger it is.
What causes birthmarks
It's not fully understood why birthmarks occur, but they're not usually inherited. Vascular birthmarks are caused by abnormal blood vessels in or under the skin, and pigmented birthmarks are caused by clusters of pigment cells.
It's thought that port wine stains occur because the nerves that control the widening or narrowing of the capillaries (tiny blood vessels) don't function properly, or there aren't 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.
Most birthmarks are harmless and don't need to be treated. Some types of birthmarks will fade over time, whereas other types such as port wine stains will be permanent if they're 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.
Some types of birthmark may need to be treated for medical reasons, while some people may choose to have them treated for cosmetic reasons.
Some haemangiomas will disappear without treatment, but they often don't change until your child is two years old.
Haemangiomas will sometimes disappear by the time a child reaches five years of age. In other cases, they may last until a child is 12.
Plastic surgery may be an option if a haemangioma has left the skin deformed or stretched. The aim of surgery will be 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.
Read more information about the complications of birthmarks.
Large or complicated haemangiomas
Some haemangiomas may cause complications that will need treatment.
A haemangioma near your child's eye, nose or mouth may cause vision, breathing or feeding problems.
Haemangiomas on the lip or around the nappy area are more likely to form ulcers that can sometimes bleed and be painful.
The exact treatment will depend on where and how severe the haemangioma is. Most haemangiomas can be effectively treated with medicine, such as oral propranolol in liquid form. This will shrink the birthmark.
If propranolol doesn't work, other medicines can be used, such as steroids or vincristine. Surgery is rarely necessary.
If your child has breathing difficulties caused by a haemangioma in their airway, they may need laser treatment.
This will usually be carried out during an examination of their airway using a small telescope called an endoscope. The procedure is known as microlaryngoscopy and bronchoscopy. They may also be given propranolol.
Occasionally, a child with an airway haemangioma may need to have a temporary tracheostomy (an artificial opening in the windpipe) to improve their breathing.
Medication may be recommended if the haemangioma is complicated or large. This is usually a beta-blocker called propranolol. The full side effects of using propranolol 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're stimulated. The noradrenaline passes messages to other parts of the body, such as the muscles, blood vessels and heart.
It's thought that propranolol helps narrow the blood vessels, reducing the amount of blood flowing through them. This reduces the colour of the haemangioma and makes it softer. The cells that cause the haemangioma to grow are also affected so that the haemangioma gets smaller.
Haemangiomas often leave a patch of stretched and thinned skin, with a small amount of swelling of the tissues under the skin. This is barely noticeable in most areas.
However, in some areas, such as the nose, lips, ears and cheek, these small changes can be unsightly. In these areas, treatment with propranalol may be considered in the first few weeks of life, immediately after the haemangioma has been diagnosed, so that the long-term appearance can be improved.
Monitoring internal haemangiomas
If your child has a haemangioma in an internal organ, they may need an ultrasound scan or magnetic resonance imaging (MRI) scan to confirm its location and size. MRI scans use a 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 fade the mark, making it less noticeable. You can also disguise it using cosmetics.
Laser treatment is the only treatment for a port wine stain. It lightens the affected area of skin. Laser treatment often works better in younger children because in adults a port wine stain may become bumpy and raised after a number of years.
The most common type of laser treatment is known as pulsed dye laser treatment. The laser passes through a fibreoptic cable. On the end of the cable is a device that looks like a pen. This is gently held 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's absorbed by the blood vessel just beneath the surface, causing it to heat up. The heat damages the blood vessel, which creates a bruise that will fade within a week or two.
During or after treatment, your child's skin will be cooled to reduce discomfort, or a jet of cold air might be blown onto the skin during treatment.
Some of the possible side effects of laser treatment are described below.
Between 3 and 30 treatment sessions may be needed at intervals of six to eight weeks.
How effective the treatment is depends on how prominent and dark the affected area is. The best results are often seen in marks that are already smaller and lighter.
You can get a prescription for a special type of camouflage make-up that covers up the birthmark.
Congenital melanocytic naevi (CMN)
As congenital melanocytic naevi (CMN) can affect a person's appearance, surgery may be considered. However, surgery will leave scarring and may not be possible if the affected area is very large.
Surgery involves removing the birthmark and stitching together the edges of the skin. If the area is large, a skin graft may be needed. This involves taking skin from another part of the body and using it to cover the wound.
Read more about how skin grafts are performed.