Before we delve further into pigmentation problems, we need to understand the basic mechanics of pigment formation in our skin. Melanocytes are cells in the skin that produce melanin (pigment). Melanocytes have arms that transfer melanin from deep to superficial layers of skin. Melanin is found in our eyes, skin and hair.
Everyone has the same amount of melanocytes. But skin colour is determined by the amount and types of melanin produced. Dark-skinned individuals produce more melanin than those with pale skin. Melanocytes produce melanin in response to UV rays to protect the skin.
Accumulation of melanin darkens skin, giving a tan. If UV rays exceed what can be blocked by your melanin level, sunburn results. Therefore, fair-skinned individuals tend to get sunburn easily. When there is excessive melanin being produced or when melanocytes clump up in the skin, pigmentation disorders appear.
COMMON PIGMENTATION PROBLEMS
Melasma is very common in Asia. It is characterized by symmetrical brown patches on the forehead and cheeks with frequent involvement of the nose bridge, upper lip and chin. Age of onset is usually the thirties and it is much more common in women than men. Risk factors in acquiring this hard-to-treat disorder are UV exposure, heredity and hormonal changes (pregnancy, OCP and perimenopause).
Freckles – Commonly seen on the cheeks and chest in the fair-skinned. They are small, brown specks that occur due to increased amount of melanin in response to UV exposure. Freckles lighten with sun avoidance.
Solar lentigo or age spots are flat brown patches on sun-exposed parts of the body i.e cheeks, temples, shoulders. As opposed to freckles, the colour of solar lentigo is persistent.
Moles occur when there is an irregular accumulation of melanocytes in the skin. We pay more attention to moles as there is a tendency for a mole to evolve to become cancerous. A cancerous mole is termed melanoma.
Hori’s nevus are symmetrical spots on the cheeks. In Hori’s nevus, melanocytes are found deep in the skin (dermis, therefore giving it the characteristic bluish-grey appearance. It commonly occurs together with melasma and is equally difficult to treat.
Another often forgotten yet significant pigmentation problem in Asians is the post-inflammatory hyperpigmentation (PIH). It is the darkening of skin in and around a wound (i.e acne) that has healed and UV exposure is the cause. The darker the skin type, the more severe the resulting PIH, if ever the skin is injured.