Skin color is a manifestation of genetics and environmental factors. The cells that determine skin color are known as melanocytes. These cells are found throughout the upper layers of the skin and produce granules of melanin pigment. Melanin granules diffuse into the surrounding skin cells known as keratinocytes and protect the cells' DNA from damage caused by ultraviolet radiation. Contrary to popular belief, a suntan is actually sun damage and does not provide protection from the sun.
What is hyperpigmentation? Many factors can affect the normal function of the melanocyte and therefore cause a variety of pigmentation disorders. Normal, healthy skin is evenly colored and free of blemishes. This results from the synthesis of a normal amount of pigment from melanocytes and its transfer to the outer layers of the skin. Ultraviolet exposure, inflammation, hormonal changes, drugs, acne, skin diseases and a genetic predisposition can increase melanin production and cause dark pigmented patches to appear on the skin. This is called hyperpigmentation.
Hyperpigmentation can affect the skin color of people of all races. What are the different types of hyperpigmentation? Freckles are small brown spots that can appear anywhere on the body but are most commonly seen on the face and arms and other sun exposed areas. Freckles are more common in fair skinned individuals as a result of sun exposure. Therefore, they can occur even in children. Freckles are most prominent in the summer but will fade in the winter as old skin cells are shed and replaced by new ones.
Sunspots, age spots, or 'liver' spots are a very common form of hyperpigmentation. They are basically superficial collections of melanin which accumulate in the top layer of the skin. Sunspots occur as a result of cumulative sun damage over many years. They appear as small, dark patches that are commonly seen on the back of the hands, legs and face or other areas that are exposed to the sun. In contrast to freckles, they persist for long periods of time and do not fade in the winter months. It is very important to distinguish the harmless solar sunspot from early melanoma. If the spot is new, contains more than one color or has irregular borders or if in doubt, consult a dermatologist.
Melasma is more commonly seen in women but about 10% of patients are men. It is more frequent in persons with brown or black skin or from Asia, the Middle East, India and South America. Melasma looks similar to age spots but tends to involve larger areas. The lesions can be well-defined or have irregular, so-called, geographic borders and typically appear on the central part of the face i.e. the forehead, nose, upper lip and chin. Melasma is precipitated by hormonal changes as seen in pregnancy, sun exposure and with the use of certain drugs such as oral contraceptives, anti-seizure and anti-malarial medications. Post-inflammatory hyperpigmentation is usually a problem for individuals with darker skin.
It develops as a result of irritation or injury to the skin as seen with acne, psoriasis, eczema and trauma. The darkened areas on the skin are limited to the site of the inflammation and have more indistinct, feathered borders. In this condition, the pigment cells tend to deposit melanin in both the superficial and deeper layers of the skin. How is hyperpigmentation treated? The successful treatment of hyperpigmentation must include the daily use of a sunblock. Freckles, age spots, and other dark skin patches can become darker and more pronounced when skin is exposed to the sun. This happens because melanin absorbs the energy of the sun's harmful ultraviolet rays in order to protect the skin from overexposure. This process darkens the areas that are already hyperpigmented. Therefore, it is essential to use an opaque sunblock every morning that contains titanium dioxide and/or zinc oxide. Light in the visible spectrum can darken pigment. Even sunscreens with the highest SPF are not effective in blocking visible radiation. A single day of excess sun exposure can undo many months of treatment for pigment disorders.
Bleaches lighten and fade darkened skin patches by slowing the production of melanin. Prescription strength creams that lighten the skin contain hydroquinone. Skin bleaching can be a long and tedious process. Therefore, to achieve faster results, hydroquinone has been found to be more effective in combination with other agents. These products include alpha hydroxy acids such as glycolic and mandelic acid, vitamin A derivatives such as retin-A and Tazorac and Vitamin C. Even alone, these agents can help to eradicate blotchy discoloration as well as exfoliate the discolored skin. Pigmented lesions can be treated by mechanical agents that exfoliate the skin such as microdermabrasion and/or erbium lasers that vaporize the skin. Exfoliation and vaporization remove superficial pigmented skin cells and also facilitate the penetration of bleaching agents. Finally, pulsed light treatments can effectively and precisely treat pigmented lesions. Light is selectively used to target the pigment without damaging the normal surrounding skin.
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