Sun Protection

• Dermatologists recommend that you apply a sunscreen daily with an SPF of at least 15.
• Additionally, it is important to be certain that the sunscreen you are using blocks both the ultraviolet A and ultraviolet B rays. Ultraviolet A rays are the rays that tan the skin and ultraviolet B are the rays that burn the skin. Both UVA and UVB rays contribute to skin cancer while UVA rays are primarily responsible for skin aging.
• It is important to remember that sunscreens lose their effectiveness when you are sweating or swimming, so you need to reapply sunscreen every two hours while engaging in outdoor activities.
• Use at least one ounce of sunscreen per application. This is the amount that fills a shot glass.
• As part of a comprehensive sun protection program, you need to also wear sun protective clothing like hats and long sleeve shirts
• Make sure to schedule outdoor activities either early in the day or late in the afternoon to avoid the peak hours of the sun (between 10 a.m. and 4 p.m.).

This prevention strategy helps keep skin looking young and healthy.

How Sunburns and Sun Tans Work

by Marshall Brain

How Sunlight Works

Sunlight arrives on earth in three forms: infrared (heat), visible light and ultraviolet. Ultraviolet light is classified into three categories:

• UVA (315 to 400 nm), also known as black light, which causes tanning
• UVB (280 to 315 nm), which causes damage in the form of sunburn
• UVC (100 to 280 nm), which is filtered out by the atmosphere and never reaches us

99% of the sun's UV radiation at sea level is UVA. It is the UVB that causes most of the problems related to sun exposure: things like aging, wrinkles, cancer and so on, although research is increasingly implicating UVA as well.

One of the interesting things about UV radiation is that it is reflected by different surfaces. These reflections can amplify the effects of UV exposure. For example, snow reflects 90% of UV light. That is why you can get snow blindness and severe sunburns from skiing on a sunny day. Sand can reflect up to 20% of UVB that hits it, meaning that you can get extra UV exposure at the beach.

On the other hand, certain things absorb almost all UV radiation partially or completely. Glass is one of these substances - many glasses are very good absorbers of UV (which is why you may have heard that you cannot get sunburn in a greenhouse - just make sure it is glass and not plastic covering the greenhouse!). Most sunscreens use chemicals that have the same UV-absorbing properties.
Howstuffworks.com

The SPF Debate

To figure out how much protection a sunscreen provides, most consumers turn to a simple number: the SPF, or sun protection factor, listed on the label. Studies show that most consumers understand that the higher the number, the more the product protects the skin.

Unfortunately, studies also show that people often have the mistaken notion that the higher the SPF number of the sunscreen they use, the longer they can stay--and will stay--in the sun. In August 1999, the Journal of the National Cancer Institute published a study showing that use of higher-SPF sunscreens led to increased sun exposure. Two groups of French and Swiss volunteers used unlabeled sunscreen during their vacations. One group used SPF 10 and the other group used SPF 30. The group using the higher-SPF sunscreen spent 20 percent more time in the sun (72.6 hours vs. 58.2 hours) than the group using the lower-SPF sunscreen.

"Because of variations between individuals, products, exposures, and conditions of use, there is no really easy way to explain SPF in a few words," says FDA's Lipnicki. "In the past, it was explained in terms of the amount of time you could stay in the sun longer with sunscreen than without it before getting 'burned'. We have gotten away from that. Sunscreen should not be used to prolong time spent in the sun. Even with a sunscreen, you are not going to prevent all the possible damage from the sun. Some of the newer research in the last several years shows that the sub-erythemal doses [exposure to the sun that does not cause reddening of the skin], as little as one-tenth the energy needed to get a sunburn, start the process of skin damage of one sort or another."

In the final monograph completed last year, FDA proposed limiting SPF values on a sunscreen label to 30. Products with higher SPFs would be labeled "30+" (or "30 plus"). The agency took this action for two reasons: inadequacies in the testing methodologies for higher-level SPF formulations, and concern that the high SPF labeling may lead consumers to spend more time in the sun than they should.

The SPF portion of FDA's monograph immediately produced opposition from both industry groups and consumer organizations. The National Coalition for Sun Safety, an organization supported by the American Academy of Dermatology, advocated "a floor rather than a cap on SPF," wrote coalition co-chairmen Rex Arnonette, M.D., and Roger Ceilley, M.D. The organization wants a minimum level of SPF to ensure that all products provide some protection.

Industry, primarily represented by the Cosmetic, Toiletry and Fragrance Association (CTFA), opposed the 30-plus cap for several reasons, including consumer confusion, fear that manufacturers would remove effective sunscreen protection in their products to avoid misbranding, and unresolved scientific issues about UVA. With the deferral of the monograph's implementation, the industry, along with the agency, will have additional time to resolve the issues.

Table of Contents
FDA Consumer magazine
July-August 2000

UVA vs UVB Rays

The complexities of light quickly overwhelm freshmen physics students, but some basic principles can be readily understood. In one model of how light works, the electromagnetic radiation can be thought of as a series of waves, like ocean waves at the beach, steadily marching toward shore. At the beach, the wind makes the waves by transferring kinetic or mechanical energy into the water. The harder the wind blows, the more energy in the water and the higher and closer together the ocean waves. On a calm summer day, widely spaced waves lap mildly against the shore. During a hurricane, the wave action intensifies, pounding the sand with closely packed wave after wave of crashing white foam strong enough to wipe away the beach.

The electromagnetic energy in sunlight works much the same way: The higher the energy of the light, the closer together its waves. Some types of light have waves that are far apart--like ocean waves on a calm day. Other types of light have waves that are packed closely together, like ocean waves on a windy day.

This difference in closeness of a light's waves, its wavelength, gives different parts of the electromagnetic spectrum its characteristics, such as the colors of visible light and the destructive capabilities of x-rays and ultraviolet light.

Physicists classify ultraviolet light into three types, by its wavelengths: UVA, UVB and UVC. The dimensions of their wavelengths are roughly 400 to 320 nanometers (nm) for UVA, 320 to 290 nm for UVB, and 290 to 200 nm for UVC. Although it may seem backwards, the shorter the wavelength and the lower the number, the greater the energy level of the light and the more damage it can do. For example, direct exposure to UVC for a length of time would destroy the skin. Fortunately, UVC is completely absorbed by gases in the atmosphere before it reaches the ground.

The longer wavelengths of UVB and UVA, however, pass right through the atmosphere, even on a cloudy day. That's why you can still get sunburned on a cloudy or hazy day. The molecules in sunscreens absorb most UVB and prevent it from reaching the skin just as the molecules of the atmosphere absorb UVC and prevent it from reaching the ground.

UVA, however, is another story

According to a 1998 review article, most sunscreens do not protect the skin from the longer UVA wavelengths. And that may be critical to the creation of skin cancer. Approximately 65 percent of melanomas and 90 percent of basal and squamous cell skin cancers are attributed to UV exposure.

The precise wavelengths of ultraviolet that contribute to the formation of skin cancer still need to be sorted out. And scientists must still figure out how best to formulate sunscreens to provide effective protection against these wavelengths.

Scientists use a number of techniques to measure the UV-blocking ability of a sunscreen. Some rely on electronic laboratory equipment, some on living tissue or live animals. Some testing procedures even use human volunteers.

"We have a good way of measuring UVB protection with a sunburn or erythema test in humans," says Sharon Miller, an optical engineer in FDA's Center for Devices and Radiological Health. But scientists lack a simple measure of UVA's impact on the skin, she says. That makes it difficult to determine how much UVA protection a sunscreen provides.

That leaves FDA with an unresolved technical dilemma that it is trying to resolve through additional research. "We are trying to determine a testing method that will demonstrate that a sunscreen is providing UVA protection," Lipnicki says. A claim such as "broad spectrum" on a sunscreen label needs to be supported by evidence that the product provides significant and meaningful protection across the entire UVB/UVA spectrum.

To Australia's Robin Marks, however, the issue is not UVA vs. UVB or even UVA combined with UVB. "The most common skin cancers seen in humans are related to sunlight, not to a limited band of the solar spectrum," Marks says. "It is the whole of all light coming from the sun. Don't concentrate on one band, but the entire spectrum. Keep it off the skin."

Skin Cancer and You

Nanette J. Liegeiois, M.D., PhD.
Assistant Professor
Johns Hopkins University

The purpose of this session is to provide an overview of skin cancer with respect to the occurrences, causes and prevention of this type of cancer. The specific objectives are to enable the attendees to understand:
1. that the rate of skin cancer is increasing
2. how to tell if something is suspicious
3. how protect oneself from skin cancer

The rate of skin cancer is increasing

• In the U.S., the incidence of skin cancer is greater than that of all other cancers combined
• One in five children will experience skin cancer during their adult lifetime
• In 2001, 1.3 million new cases of skin cancer were diagnosed
• From 1950 to 2000, there was a six times increase in the annual diagnosis of cutaneous melanoma and a 165% increase in annual mortality
• Melanoma is increasing more rapidly than any other type of cancer
• High risk groups, such as patients with familial melanoma syndrome, chronically immunosuppressed, and those who have had high sun exposure and have fair skin, should be monitored closely for cutaneous malignancy
  Early diagnosis can be life-saving because while skin cancers have a much lower rate of mortality compared with other cancers, late stage skin cancer is extremely devastating
• Risk of recurrence or metastasis depends on whether a tumor is low or high risk
• Prognosis for less invasive lesions is far better than those with greater invasion
• Skin cancer has a tremendous impact on our society. Although it is not one of the more deadly cancers, it has become one of the most costly. The total cost of Medicare expenditure on cancer management was $13 billion per year. Skin cancer is one of the top 5 most costly cancers (including lung/bronchus, prostate, colon/rectum and breast)

How can you tell if something is suspicious?

Your physician will look at your skin during a complete physical examination but it is important for you to point out things that are new or have changed. A "freckle" that has been present for a long time and "suddenly changes" is of much more concern than a darkly pigmented congenital mole that has been present since birth and has not changed. Although some skin cancers bleed, the vast majority do not. If someone in your family has had skin cancer or if you have had a significant amount of sun in your life, your physician should know. Also, people on certain medications need to know about their risk factor for skin cancer. An abundance of moles is also an independent risk factor for the development of melanoma. It is advisable to have a dermatologist perform an examination on any high risk patient.

Basic Skin Examination

In performing a skin self examination, it is important to be systematic. Start with the face: carefully examine the entire skin surface, including the scalp, ears, neck. Skin cancer occurs with high frequency on the scalp and ears for men. A thorough skin examination includes the genital and mouth surfaces
1. Actinic keratosis is a pre-malignant lesion which can often be mistaken for dry flaky skin. Patients with many of these have a higher tendency to develop non-melanoma skin cancer
2. Basal cell carcinoma occurs in many forms and types. Typically, it is a pearly lesion that occurs on sun exposed skin. The majority have very faint blood vessels on the skin surface
3. Squamous cell carcinoma can be flaky, like the actinic keratosis, but usually has more substance to the tumor

Benign Pigmented Lesions

1. Freckles tend to occur on lightly pigmented individuals and are an indication of significant sun exposure. They tend to be very bland and small in size. Any freckle that is unusual in shape, size, or varied in pigment color should be closely evaluated
2. Benign moles (nevi) are extremely common and include lesions that have non-variegated color and border. Any benign nevus can change to become a more serious malignant nevus or melanoma, so careful examination by your doctor is necessary

Pigmented Lesions

1. An atypical mole is a possible concern and should be followed by a dermatologist
2. There are many forms of melanoma. A safe guideline for primary care physicians is to use the ABCD criteria:

A: Asymmetry
B: Borders- are they irregular?
C: Color-is it strange or multicolored?
D: Diameter- is the diameter increasing or large in size?
If a lesion meets any of the ABCD criteria, further evaluation is warranted

How can I prevent Skin Cancer?

1. Sun Avoidance: It is important to educate patients regarding the harm the sun can cause. Generally, it is best to avoid direct sunlight from the hours of 10 a.m. to 2 p.m.
2. Sun Protective Clothing: There are several lines of clothing that are effective at blocking the damaging rays of the sun. This is particularly advisable for those who enjoy several hours of outdoor activities daily. Many clothing lines offer lightweight and breathable fabrics that have SPF up to 50.
Some examples found online are:

www.solumbra.com
www.sunstoppers.com
www.sundayafternoons.com
www.tilley.com
www.coolibar.com
www.sunsolutionsclothing.com
www.radicool.msp-direct.com
www.traseusa.com

3. Sunscreen: There are several types of sunscreen. The most effective sunscreens block both the A and B types of ultraviolet light.
4. Physical blockers: Titanium dioxide and Zinc oxide are two physical blockers used in sunscreens. Look for these agents in sunscreen to block all harmful wavelengths of light. For people at high risk, this is the most advisable form of sunscreen.

Sunscreen Review

What are sunscreens and how do they work?
Sunscreens are chemical agents that prevent the sun's ultraviolet radiation from reaching the skin. Two types of ultraviolet radiation, UVA and UVB, cause damage to the skin. Until recently, most sunscreens have only blocked UVB, however a number of UVA blocking products are now available. When applied regularly, and skin cancers. They work by either absorbing or reflecting ultraviolet radiation, thereby preventing damage to the skin.

What is SPF?

SPF, or sun protection factor, is a measure of a sunscreens' ability to prevent UVB from reaching the skin. In practical terms, one SPF is the amount of time a person can spend in the sun before developing a sunburn. Each increased SPF level increases the time that an individual can spend in the sun by one SPF. As an example, by applying an SPF 15 sunscreen, an individual who would get a sunburn in 10 minutes without any sunscreen, can spend 150 minutes in the sun without getting burned. Newer sunscreens, usually labeled "broad spectrum" or "UVA/UVB" contain chemicals that block UVA radiation as well.

Who should use sunscreens?

We recommend daily use of sunscreen, applied to all exposed areas of skin, for anyone over the age of 6 months, regardless of their skin type and likely sun exposure. Even those who work inside are exposed to ultraviolet radiation for brief times throughout the day. Also, UVA is not blocked by most windows. For children under 6 months of age, most doctors advise clothing and shade as the primary means of protection from the sun. For children in the age group, sunscreens should only be applied in cases of prolonged exposure and should be applied sparingly only to exposed areas of skin.

What sunscreen should I use?

The answer depends on how much sun exposure one is anticipating. In all cases we recommend a broad spectrum sunscreen, which means it blocks both UVA and UVB. Most sunscreen agents block either UVA or UVB and therefore must be combined in order to get broad spectrum protection. In the United States there are a large number of sunscreens available as spray-on products and lotions. The only single broad spectrum agents available in the U.S. are titanium oxide and zinc oxide. Both products, depending on the formulation, tend to leave a white film residue on the skin, which limits their popularity. Newer sunscreen agents such as Mexoryl and Tinosorb are available internationally in a variety of sunscreens. These are single agents (though often combined with other sunscreen agents) with broad spectrum protection, and excellent cosmetic appeal, but neither has been approved in the United States. Many make-up products and moisturizers have a sunscreen (usually SPF 15 or greater) already in them, and this is sufficient for people that spend little time in the direct sun. For people that work outside or spend significant time outdoors, we recommend a sunscreen that is broad spectrum, at least a SPF 15, and "water-resistant" or waterproof." The "water-resistant" and "waterproof" products are also less likely to drip into the eyes,which makes them ideal for people wearing a sunscreen on hot days or while they are perspiring. Sunscreens used regularly on the face should be non-comedogenic (which means they will not clog the pores) because products not designed for the face can actually cause or worsen acne.

What else can I use to protect myself from sun damage?

People who will be sweating heavily or spending time immersed in water should use "water-resistant" or "waterproof" sunscreens, but even these must be reapplied (see directions on bottle for specific time suggestions). Sunscreens are only one part of protecting yourself from the sun; consistent use of sunglasses, wide-brimmed hats, long-sleeves and pants, umbrellas, and other sources of shade are critical behaviors to obtain more complete sun protection.

How much sunscreen should I use and how often should I put it on?

The tests done to determine a sunscreen's SPF require 1 oz to be applied over the entire body. Most studies show that people apply only half to a quarter of that amount, which means the actual SPF they have on their body is lower than expected. During a long day at the beach one person should use essentially 1/2 to 1/4 of a standard 8oz bottle. Sunscreens should be applied 15 to 30 minutes before sun exposure. Because some sunscreens are actually broken down by the sun and/or washed off by sweat/water, the SPF of sunscreens decreases with time and reapplication of a sunscreen is critical. There are no studies that show the best schedule but every 2 to 3 hours is probably adequate if one is not immersed in water or sweating profusely.

Common Myths

1. Wearing sunscreen can cause vitamin D deficiency. Fortunately this is not true. For patients that are still concerned about vitamin D deficiency there are excellent dietary supplements available.
2. If it's cold or cloudy outside, I don't need sunscreen. This also is not true. Up to 40% of the sun's ultraviolet radiation reaches sea level even on a completely cloudy day. This misconception often leads to the most serious sunburns, because people spend all day outdoors with no protection from the sun.
3. 80% of your sun exposure comes as a child so it's too late to do anything now. There are many studies that challenge this idea. In fact, the best studies to date on the effectiveness of sunscreens are done in adults, and they show that sunscreens prevent the development of precancerous skin conditions. Because adult Americans are living longer and spending more leisure time outdoors, preventing on-going skin damage is very important.
4. Using a sunscreen higher than SPF 30 does not block out any more sun. Actually, every increase in SPF prevents more sun from reaching the skin. SPF 30 sunscreens block more than 97% of the sun's rays from reaching the skin. If sunscreens are used correctly, the added protection from higher SPF sunscreens is very small, but is real. Very effective sun protection can be found by other chemicals, including Aminobenzoates, Cinnamates and Salicylates. All of these block UVB light, which contains the harmful ultraviolet rays that damage the DNA and cause skin cancer. When these chemicals are combined with UVA blocking chemicals, such as Benzophenones, Oxybenzone, Methyl Anthranilate, Avobenzone (Parsol 1789), (Butylmethoxydibenzoly methane), a complete block is formed.