Sun Damage Prevention & Correction

Sun Damage Correction

Finally there are skin care products and treatments from Obagi Medical Systems that are scientifically proven to change the health and structure of your skin on a cellular level. This means you can achieve the changes you want such as smooth, radiant skin with a significant reduction of fine lines, pore size, surface blemishes, wrinkles and pigmentation.

Sunlight and the Skin

The need for daily sunscreen use has become increasingly evident over the last several decades. As we spend more recreational time in the sun than ever before, there is a growing awareness of the harmful effects of sunlight exposure. Photoaging and photocarcinogenesis are the most important results of chronic sun exposure. Photoaging is defined as light-induced skin damage that results in a prematurely aged appearance. Photocarcinogenesis means light-induced skin cancer. Sunlight exposure has been shown to be an important factor in causing skin cancers. Since the 1970s, researchers, dermatologists, and cosmetic chemists have worked together to develop products to protect the skin from sun damage. This damage comes from Ultraviolet A (UVA) and Ultraviolet B (UVB) radiation from the sun.

Signs of Sun Damage

The earliest changes of sun damage in the skin are freckles and small, dilated blood vessels. More advanced sun damage leads to rough, scaly red spots called “keratoses", bumpy leathery texture of the skin, and an increase in wrinkles giving a prematurely aged appearance. Later, skin cancers appear as either growths that continued to bleed and scab without healing, or moles or freckles that develop a dark black color. For most of us, the damage from the sun is done in our teens and twenties but skin cancers and signs of chronic sun damage can show up 20 to 30 years later - long after the damage has been done!

The Solar Spectrum

The regions of the solar spectrum that are the most significant for us are the ultraviolet, visible, and infrared. Ultraviolet rays are responsible for most sun-induced damage in the skin. Ultraviolet radiation in sunlight is divided into three categories based on wavelength and biologic effects: UVA (320-400 nanometers), UVB (290-320 nm) and UVC (100-290 nm). UVA radiation mostly reaches the Earth’s surface unfiltered. UVB radiation is partially blocked by the ozone layer. UVC radiation is completely absorbed by the ozone layer before it reaches the Earth’s surface.

Ultraviolet A activates both an immediate pigment-darkening reaction in the skin and a delayed tanning reaction. The sunburn potential of UVA is weak, about 1000 times less than that of UVB. However, 10 to 15 times more UVA than UVB reaches the Earth's surface and remains relatively constant throughout the day. UVA is a longer wavelength of light energy that penetrates deeper into the skin. This penetration can reach the blood vessels in the skin, irradiating circulating cells in the bloodstream. UVA is the frequency of light that is used by tanning parlors and is falsely claimed to be the “safe rays” from the sun. UVA is known to cause melanoma (a dangerous form of skin cancer), premature aging of the skin, decreased immunosurveillance against skin cancer, and a permanent increase or decrease in pigmentation. UVA also passes unfiltered through window glass. Window glass does not transmit UVB.

Ultraviolet B is a shorter wavelength of light energy that is responsible for the typical sunburn. Skin cancers such as basal cell carcinoma or squamous cell carcinoma and pre-cancerous growths called actinic keratoses are caused by continuous UVB exposure, especially in the first 20 years of life. Melanoma has also been shown to be caused by repeat UVB sunburns. UVB is the most effective wavelength to stimulate erythema (inflammation) in the skin, thus it is known as the "sunburn" rays. Erythema is maximal approximately four hours after exposure. UVB irradiance is greatest between 10 a.m. and 2 p.m. Use of a UVB-only sunscreen will allow users to stay in the sun longer than ever before, leading to a higher amount of UVA being absorbed.

Sun Protective Factor (SPF) Measurement

Currently, the SPF refers to the level of UVB protection only and says nothing about UVA protection. An SPF of 30 or higher is recommended but the label should include the words Broad Spectrum or Blocks UVA/UVB. For fair-skinned individuals, a higher SPF is advisable. Surprisingly, a "base" tan will not effectively reduce the likelihood of sunburn in a sunny climate. Tanned skin has an SPF of only 2 to 4.

Mechanism of Sunscreen Action

When ultraviolet energy strikes the skin, some of the energy is reflected, some is absorbed, and some is transmitted inward to deeper layers until the total energy has dissipated. Sunscreens are used to both absorb and reflect damaging ultraviolet wavelengths. Energy is converted into harmless long-wave radiation which is then emitted by the production of mild heat which is not perceived.

Sunscreens/Sunblocks

Physical (Inorganic) Sunblocks are opaque formulations that reflect and scatter ultraviolet and visible radiation. The two major sunblocks titanium dioxide and zinc oxide are very effective because of their ability to scatter and absorb both UVA and UVB radiation. They are hypoallergenic and have a good safety profile. The major drawback in the past has been their physical appearance. Recently, micronized formulations (smaller particles) of these two ingredients have allowed for greater cosmetic acceptance. For a pure physical (chemical-free) sunblock, we recommend Dermatologic Cosmetic Laboratories UVA/UVB Chemfree Superblock SPF 30, SkinCeuticals Physical UV Defense SPF 30 (for normal to dry skin), and SkinCeuticals Sheer Physical UV Defense SPF 50 as a very lightweight  mattifying fluid sunblock with a transparent finish This product has a unique ‘shake then apply’ action which assures even distribution of the active ingredients in this silky sheer fluid that dries quickly and leaves no residue. We also recommend La Bella Donna Loose Mineral Foundation as an excellent mineral makeup that acts as a broad spectrum sunblock with an SPF of 20.

Chemical (Organic) Sunscreens absorb ultraviolet energy as it strikes the skin. Mexoryl is the most recently FDA-approved sunscreen that provides superior protection against UVA rays. Avobenzone (Parsol 1789) is another popular ingredient available for UVA protection. However, Avobenzone tends to be photo-unstable and cannot be combined with Octinoxate. One of these UVA sunscreens is typically combined with one or more UVB sunscreens such as Padimate O, Cinnamates, Salicylates, and Octocrylene for broad spectrum coverage.

Combination Sunscreens contain both physical sunblocks and chemical sunscreens. The most cosmetically acceptable ones contain micronized zinc and Octinoxate. Octinoxate is the most powerful UVB filter available in the United States, is water resistant, and has low skin irritancy potential. We recommend Dermatologic Cosmetic Laboratories Super Sheer Sunscreen SPF 50+; and Obagi Nu-Derm Sun Shield SPF 50;

Antioxidants can also be added to provide and extra level of sun protection. We recommend Journée Bio-restorative Day Cream SPF 30 by Neocutis which contains green tea extract, vitamins C + E, hyaluronic acid, and Human Growth Factors; Citrix Antioxidant Sunscreen SPF 30 which contains green tea, vitamins A, C, and E and Coenzyme Q10; Revaléskin Day Cream SPF 15 with CoffeeBerry®; and Heliocare by Biopelle which uses a natural fern extract as a potent oral antioxidant that is taken as a dietary supplement on a daily basis.

Conclusions

Sunscreens should be used all year long on a daily basis regardless of the weather. They are applied each morning after washing. Even on cloudy days, enough UVA and UVB radiation get through to cause a significant amount of damage. Avoid high intensity midday sunlight, wear sun-protective clothing including wide-brimmed hats and light weight long-sleeved shirts, and stay in shaded areas when possible. Use a UVA/UVB broad spectrum sunblock that has an SPF of at least 30 and reapply during the day, especially if you are swimming or sweating excessively.

Always remember slip, slap, and slop:
Slip on a shirt.
Slap on a hat.
Slop on the sunscreen.

All highlighted brands of sunscreens and sunblocks are available for purchase in our office.
They are also available at our web store www.TheWebDermatologist.com

Labor Day 2010 at a beach in Florida. Dr. Schwartz wearing a SunDay Afternoons hat, DCL UVA/UVB Chemfree Superblock SPF 30, Costco sunglasses and a long sleeve Nike shirt.