What Are Birthmarks, Why Do They Occur, and How Are They Treated?
A birthmark is a benign irregularity on the skin which is present at birth or appears shortly after birth, usually in the first month. They can occur anywhere on the skin. Birthmarks are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes.
Most birthmarks are harmless and do not require treatment. Pigmented marks can resolve on their own over time in some cases. Vascular birthmarks may require reduction or removal for cosmetic reasons. Treatments include administering oral or injected steroids, dermatological lasers to reduce size and/or color, or dermatologic surgery.
There are a number of common skin marks that are present at birth and are referred to collectively as “birthmarks”. They tend to involve overgrowth of structures that are normally present in the skin such as blood vessels (in which case they are called vascular marks or haemangiomas) or pigment cells (in which case they are called moles). The cause is unknown. For most babies they don’t create major problems and most birthmarks do not require any treatment.
Vascular Marks (haemangiomas): The most common vascular mark is the salmon patch or “stork bite” seen as a flat red mark at the back of the neck in up to 50% of children at birth. It can occasionally occur elsewhere on the head or neck. The majority on the face clear within five years but those on the back of the neck tend to remain.
A raised form of vascular mark is the true haemangioma, or strawberry naevus. It appears some months after birth, in contrast to the salmon patch which is present at birth. It grows rapidly over six months to form a red raised soft area which can vary in size from half a centimetre to several centimetres. Up to 10% of infants may develop these haemangiomas.
Most of them eventually shrink and disappear without treatment. Occasionally, a large one that is growing rapidly in a special area such as around the eyes, the nose, or the mouth may require treatment. This can be done with special laser treatment. Occasionally, a very short course of cortisone, prescribed by a doctor, taken by mouth will stop the growth of one of these large haemangiomas.
Pigment Marks: Pigment marks are due to an increase in the normal pigment cells (melanocytes) in the upper layers of the skin. The most common one is the Mongolian spot. This is a flat area of Gray-Brown or Blue-Gray pigmentation which occurs most commonly on the lower back.
These are present at birth and are not harmful. They are more common in babies with olive or darker skin (over 90% of Asian infants have them compared with 5% of Anglo-Saxon infants). Mongolian spots eventually fade over time.
A congenital melanocytic naevus (birth mole) is a harmless growth of the pigment cells which may be present at birth or appear within the first few months. These spots vary in size from millimetres to several centimetres and may be raised and able to be easily seen and felt compared with a Mongolian spot which is not raised.
Most moles which are present at birth do not have any increased risk of developing cancer and therefore do not require treatment. However, occasionally the very large ones, more than 20 cm wide may be a risk factor for skin cancer. The forms of treatment available for these large moles include surgical removal or occasionally laser therapy.
Freckles are not normally present at birth. They are an increase in the color produced by pigment cells (melanocytes). They occur in early childhood with exposure to moderate to large amounts of sunlight on the areas most exposed, e.g., the cheeks, the back of the hands or back of the forearms. Freckles may be able to be prevented by good sun protection. The majorities of moles is not present at birth and tend to appear during childhood and adolescence.