There are several different types of birthmarks.
The most common birthmark is the so-called "stork bite" which occurs on the back of the neck. The lesion is flat, reddish and of variable shape. It is caused by dilated blood vessels, which may fade after about a year or most often becomes covered by the child’s hair and is then no longer visible.
A birthmark is a skin blemish which is present at birth and which has usually developed before the baby is born. Birthmarks enlarge in proportion to the growth of the child.
The different types of vascular birthmarks
Vascular birthmarks are composed of blood vessels.
Port wine stain
Port wine stains are always present at birth. These are pinkish, red or purple lesions. They result from dilated capillaries (tiny blood vessels) in the dermis of the skin and are permanent. The dermis is the layer of skin immediately below the skin surface.
The head and neck are the most common sites affected. The blemish is usually only present on one side.
As the child gets older, the port wine stain may get darker. Occasional raised areas which bleed spontaneously may develop.
Very rarely, a port wine stain is a sign of an underlying medical problem such as Sturge-Weber syndrome.
Treatment with laser is successful, after which the texture of the skin is generally normal, with no scarring. Treatment can begin when the child is very young.
Laser treatment is not universally successful and the procedure is expensive.
Strawberry naevus – capillary haemangioma
A strawberry naevus is a bright red, protuberant, sharply-demarcated lesion, which can occur on any area of the body.
They are sometimes present at birth. More often, however, they appear within the first two months. They start as an area of redness or even an area which is paler then the surrounding skin. These lesions then develop fine surface blood vessels before starting to grow in size. Girls are affected more than boys. The most common sites are the face, the scalp and the back and front of the chest. Lesions are usually solitary. Most expand rapidly at first, stabilise and then slowly disappear without treatment.
The course of a particular lesion is unpredictable. However, around 60% disappear by the age of five years. By the age of nine, around 90-95% disappear.
Complications include ulceration, secondary infection, and rarely, bleeding.
Sometimes the lesion can occur over a vital part of the body, such as the eye or the urethra (opening from the bladder), in which case treatment is indicated. Systematic corticosteroids or laser treatment should be considered.
Since most capillary haemangiomas disappear by themselves, no treatment is needed and attempts at surgical removal may be harmful. After the lesions have disappeared, about 10% of children will be left with some puckering or skin discolouration. This can usually be dealt with by plastic surgery if required.
Cavernous haemangiomas are located deeper in the skin than strawberry haemangiomas. This means they appear to be more diffuse and less well-defined. The overlying skin is normal or slightly bluish in colour. Like strawberry haemangiomas, cavernous haemangiomas grow, stabilise and spontaneously regress.
Rarely, these lesions press against vital structures underneath or around them. They can also interfere with sight, feeding and breathing if they are present around the eye, the oesophagus (swallowing tube) and the airways.
If treatment is required, a four-week course of prednisone is effective in some infants. Cortisone injected into the lesion can also produce rapid regression.
This is also called a vascular spider. It consists of a bright red, faintly pulsating lesion which has a central small blood vessel (arteriole) with slender projections radiating out from it, which can be likened to spider legs. The lesions vary from a few millimetres to several centimetres in diameter.
Spider angiomas are associated with conditions in which there are high levels of the circulating hormone oestrogen, such as cirrhosis of the liver and pregnancy. However, they are also found in up to 15% of normal pre-school children and in 45% of those of school age. Vascular spiders are uncommon at birth.
The most common sites in children are the back of the hand, the forearm, the face and the ears. These lesions can regress without treatment. If necessary they can be treated with laser, liquid nitrogen or sometimes cautery, in which the blood vessels are closed off using a low electric current.
Birthmarks may also occur in the form of brown spots, whitish spots, or areas of increased hairiness.
When to see your doctor
If your child has an unusual skin lesion of any type you should consult your doctor.
If your newborn baby has a skin blemish or develops one later in life, see your doctor for an explanation and diagnosis and if necessary treatment of the problem.
Previously reviewed by Prof H.F. Jordaan
Reviewed by Prof Eugene Weinberg, Paediatrician, February 2011