SKIN CARE: BIRTHMARKS
One of the first, quite natural thoughts which go through the mind of a mother as she awaits the birth of her baby is the possibility of it being born with some defect. Minor defects in the skin are not uncommon, major ones very rare.
The study of genetics concerns heredity. One has only to observe the colour and texture of one’s own skin and that of one’s children or one’s parents, to note the general similarity between them; they are, in fact, genetically alike in most respects. Such characteristics, and others, are transmitted from one generation to another by chromosomes. Chromosomes are rod-like structures, or threads, which carry a definite number of genes. The gene is composed of molecules of deoxyribonucleic acid (DNA), and the hereditary information which any one gene carries is dependent on the arrangement of the DNA molecules. The information is carried by a messenger substance to the cytoplasm by a complicated sequence of manoeuvres.
The skin defects which may be found on a baby are called developmental. Small defects are common. They are generally considered to have environmental or genetic causes. Environmental causes involve injuries to the embryo, or to the gene cells before fertilization occurs, and genetic causes are transmitted from parents.
One of the commonest defects in the skin involves the underlying blood vessels, or the pigment cells. Such small defects are called naevi or, more colloquially, birthmarks. There is no known cause for them, and usually no genetic reason. In former days they were incorrectly attributed to some shock the mother sustained during her pregnancy, or a mild illness, and some of them are still called ‘mother’s marks’ in country districts.
Birthmarks or naevi are found in over 95 per cent of white people of either sex, and to confuse the issue it must be stated that most of them are not present at birth at all.
Naevi may arise from all of the various tissues which make up the skin. The more obvious ones are those arising from the blood vessels. The most common of these is the ‘salmon paten or ‘stork bite”, which is present in about 60 per cent of infants. This type of naevus usually appears about the head and neck and usually fades completely within one year. The excessive blood vessels are very superficially situated.
With the ‘port-wine stain’, the excessive vessels are more deeply situated. These naevi also frequently appear on the head and neck, but unfortunately, usually persist. There is no effective treatment, although good masking cosmetics are available to camouflage them.
The ‘strawberry mark’ is composed of numerous capillary vessels. Such naevi are frequently multiple, and are more common on the head and neck. Most are small, but some can be very large. About 10 per cent of all infants have them, and they usually appear within the first month of life. Frequently, they enlarge quite rapidly for the first few months before stabilizing. Parents are naturally alarmed by these naevi. However they usually disappear on their own, without any treatment, by the time the child is 7 or 8 and frequently much earlier. No treatment is required unless the naevus is situated in a place where it interfere with vision or sucking, of if ulceration or haemor-rhaging occurs. Then either medical or surgical intervention may be required.
The first indication of a strawberry mark’s regression is usually a deepening of the colour, with tiny white or grey flecks appearing. These flecks then enlarge, and pale depressed areas form. Eventually the naevus shrinks and disappears, occasionally leaving a small white patch where it had been.
Those naeyi arising from pigment cells are commonly known as ‘moles’. In fact very few moles are present at birth. Most of them appear during childhood or adolescence, and are discussed elsewhere.
Various other types of naevi exist, including the so-called verrucous or ‘warty’ birthmark. These usually appear at or soon after birth, and have a linear appearance, often along one of the limbs. They normally only grow in proportion to overall growth, and invariably persist. The most opportune time to have these naevi surgically removed would seem to be either before a child commences school (about age 4) or about age 14, when the patient could have some say in the decision.
It must be remembered that all these abnormalities of the skin, although developmental In origin, may first appear at any age. They are made up of normal skin components, the proportions of which are abnormal. Therefore they are best termed naevi rather than birthmarks.
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