Thursday, October 23, 2008

Skin Pigmentation: Pigmented vs. Non-Pigmented

Posted by Alison

The pigmented vs. non-pigmented scale measures the likelihood of developing unwanted dark spots on the face or chest. Although the test will also take into account skin color and ethnicity, that is not as important as determining the tendency toward unwanted spots. That’s why people of all ethnicities can score as any of the sixteen Skin Types. That being said, in some cases, the majority of those with a particular Skin Type may come from certain ethnic backgrounds, while people from a very different ethnicity might be in the minority for that particular type.

Why do I place such emphasis on unwanted dark spots? Twenty-one percent of visits to the dermatologist are for their treatment. Over eighty thousand people annually buy over-the-counter (nonprescription) skin care products to reduce their dark spots. Various kinds of dark spots cause cosmetic concern. Birthmarks, moles, and scaling patches called seborrheic keratoses are outside of that scope.

Dark spots

Melasma, also known as the “mask of pregnancy”, consists of light or dark brown or gray patches ranging form the size of a dime to large areas on the face or chest. Appearing in sun-exposed areas, it’s more common in pregnant women or those on estrogen therapy, whether birth control pills or hormone replacement. Melasma can be stressful, in severe cases, even disfiguring. More commonly seen in darker-skinned people, such as Asians, Latin-Americans, and African-Americans, melasma is difficult to cure but can be controlled with the right skin care products and procedures. Pigmented types with any combination of the other three factors can have mlasma.

Solar lentigos are caused by sun exposure and sunburns. They’re completely preventable with sun avoidance and sun protection. Popping up on factors, like excess sun, more than genes. They contribute to the appearance of aging as much or more than wrinkles, a view shared by Asians, who are often more concerned with dark spots than wrinkles.

Yet many people focus more on wrinkles, not recognizing how spots detract from skin’s youthfulness. On the first visit, a Wood’s light (black light) or a UVB camera is used to reveal facial dark spots before they are visible in ordinary light. Most people are shocked by what they see in the mirror. If you’re an Oily, Resistant, Pigmented, and Tight Skin Type (ORPT) with ample solar lentigos, follow the recommendations aimed at wrinkle prevention for Oily, Resistant, Pigmented, and Wrinkled (ORPW) as a preventive. The good news is that my recommendations for products and procedures can make a dramatic difference in the way your skin looks.

Freckles, also called ephelides, are associated with red hair and fair skin, while solar lentigos are not, although their appearance is similar. The gene believed to be responsible for freckles is the MC1R gene, which is closely associated with fair skin and red hair. While you can’t control your genes, you can control sun exposure. Freckles appear early in childhood, increase as a result of sunburn before the age of twenty, and partly disappear with age, while solar lentigos worsen with age. Because fair-skinned redheads, those most prone to freckles, frequently burn and cannot tan, they often end up avoiding the sun, resulting in less cumulative lifetime sun exposure than people with solar lentigos. However, these fair-skinned redheads are at a higher risk of melanoma, which increases with a history of frequent sunburns and sun exposure.

Unlike people with many solar lentigos, people with freckles can fall into the tight group if they’ve avoided sun exposure and followed good skin habits, such as eating an antioxidant-rich diet, not smoking, and using retinoids.

While people with a darker skin color are more likely to fall into the pigmented category, not all dark-skinned people are pigmented types, with pigment problems. Those with even skin tones and no spots will be Non-Pigmented Skin Types, even though they have darker-toned skin. On the other hand, light-skinned people who freckle and get melasma or solar lentigos may fall into the P category. The P/N scale measures the tendency to develop unwanted dark spots, not ethnicity.

Skin pigment-producing cells (called melanocytes) produce skin pigment (melanin), which creates skin color as well as all the forms of pigmentation. Skin pigment formation can be prevented by two main mechanisms. The first is to inhibit the enzyme tyrosinase, which prevents the formation of melanin. Many topical cosmetic ingredients such as hydroquinone, kojic acid, arbutin, and licorice extract are tyrosinase inhibitors. The second method of preventing the production of skin color is to forestall the transfer of the color into the skin cells. Studies show that niacinamide and soy prevent that transfer, which is why they are in skin lightening products.

Pigmentation and Skin Cancer Risk

Pigmentation contributes to your risks of getting the various types of skin cancer. Melanoma skin cancers result when the pigment cells that produce color become cancerous. Though curable if caught early, this form of cancer can metastasize very rapidly, making early detection essential. Non-melanoma skin cancers are cancers of the skin cells themselves. There are two varieties. Basal cell cancers occur at the basal skin level between the dermis and epidermis. These can be easily removed but may scars. Squamous cells grow on the top layer of skin, and although they can metastasize, they are less deadly than melanoma. All should be checked for regularly and treated promptly.

When UV light hits the skin, it stimulates an increased production of skin pigment, which is what we call tanning. This is the skin’s major defense against further UV damage. In addition to tanning skin, ultraviolet light worsens melasma and causes sun spots (solar lentigos). UVB rays cause an immediate sunburn: UVA rays cause long-term damage. Many sunscreens do not block both types of UV light. Even broad-spectrum sunscreens do not block 100 percent of the sun. Sun avoidance is the most important method of preventing skin pigmentation.

Light-skinned people with high P scores are likely to have freckles and may also be at a risk for melanoma. Latin-American, Asians, and Italians are often on the cusp of the P/N scale.

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