sun

Doc Talk
This column is by:
By Jerome Z. Litt, M.D.

"Doc Talk" is a column dedicated to providing relevant information relating to skin care and women’s health. If you have suggestions for topics that are of interest to you, or that you believe would be of interest to other members of the Marlene Klein community, please e-mail them to us. This resource is intended only to inform, not to provide medical advice. For personal health concerns, please consult your physician. Thank you for reading. We hope that you will find this page to be of use.

July 28, 1999

SUN

SUN-RELATED SKIN CONDITIONS

The suntan conjures up images of the bronzed lifeguard and golden, tawny bodies on the beach. It is the envy of friends and relatives. However, the sad truth is that sun tanning is a dangerous habit with no demonstrable health benefits. Exposure to the sun is directly and ultimately responsible for the leathery look of prematurely aged skin, wrinkles, and skin cancer - all of which are irreversible. Excess sun exposure can also cause sun poisoning.

The serious problems potentially caused by the sun's rays are enhanced because of the recent thinning of the ozone layer in the earth's atmosphere. The ozone layer provides us with some protection from the sun's radiation. However because of our use of aerosols and propellants, the release of nitrogen oxides from nuclear explosions and supersonic transports, and the discharge of chlorine from space shuttles, this protective layer is being depleted.

The following sections describe the biological processes underlying the development of a suntan, proper tanning techniques, and the best ways to treat and prevent sun poisoning.

SUN TANNING

In contrast to the positive connotations it now confers, suntanned skin was at one time negatively associated with those who were forced to work outdoors, i.e., peasants, farmers, and serfs. People of means took pains to stay out of the sun to preserve their natural skin color. Medieval beauties were admired for their indoor pallor.

Tanning is nothing more than an efficient, protective mechanism of the skin in response to injury from sunlight. It is the body's way of protecting us from additional injury. The "healthy-looking" tan that we usually associate with good health and an attractive appearance, in reality represents damaged skin.

The tanning mechanism is not completely effective at protecting us from the harmful effects of the sun's rays. Consequently, repeated sun exposure allows certain wavelengths of light to penetrate this defense barrier, causing the various sun-related skin conditions. The more subtle skin changes caused by sun exposure may not be apparent for decades. However, they do and will occur in every person who is foolish enough to expose himself or herself to excess. Therefore, the only good suntan is no suntan at all.

Compare, for example, the sun-exposed regions of your body - your face, hands, and forearms - with those parts of your anatomy, such as your buttocks, that are almost never exposed to sunlight. Note the difference in the smoothness and texture of the skin covering these areas. The skin on buttocks appears youthful, while that covering your hands and face looks aged.

For fair-haired, fair-skinned, blue-eyed people, tanning, if it does occur, is a slow process. Light complected individuals have much smaller pigment cells than do their dark-haired, brown-eyed, darker-skinned neighbors. Therefore, they burn more easily, and require significantly more sun exposure to produce even a modest tan. By contrast, those who are dark-skinned often require only a brief exposure to the sun to obtain a lasting tan.

For light-skinned people who, despite all admonitions against doing so, still choose to tan, here are a few rules:

Acquire your tan gradually. If you head for the beaches, the backyards, or the lakes in order to soak up that first Sunday sun in June, avoid a severe and painful sunburn by limiting your first sun exposure to fifteen or twenty minutes. Increase your time in the sun gradually by twenty or thirty minutes a day for four or five more days. The first pigment cells will then begin to show up to darken and protect the skin. From then on, you will be able to tolerate almost any length of exposure.
If you are a redhead or a blond, you have fewer pigment cells than individuals with darker complexions. Therefore, you must be more careful, and should cut in half the early exposure time periods recommended above.
The previous recommendations are subject to individual variation. Only you, through trial and error, will know how much sun you can tolerate on your first and subsequent sun exposures, without having the sun cause a painful burn.
Keep in mind that the most intense rays of the sun occur between 10 A.M. and 2 P.M. (standard time), the overhead sun giving you the greatest ultraviolet exposure. You cannot get sunburned before 9 A.M. and after 5 P.M., at which times the sharply angulated "burn" rays have been filtered out by the atmosphere.
Don't let overcast skies fool you. You can get a sunburn on hazy and foggy days. Furthermore, reflected rays from sand, cement, and water can also cause severe sunburns. Beach umbrellas do not offer absolute protection from sunburns, and you can even get sunburned while swimming under water!
Use suntan creams and lotions. Many commercial suntan preparations contain chemicals that selectively absorb the shorter (higher energy) wavelengths of sunlight that are responsible for burning, while permitting some of the longer (lower energy) wavelengths of light - the tanning rays - to penetrate the skin.

People are classified into various skin types depending on the relative amounts of the skin pigment melanin they contain. The simplest classification is as follows:

Skin Type I: People with fair hair and fair skin or freckles. These individuals are most susceptible to the rays of the sun, and can develop a severe sunburn in a matter of minutes. They also have a higher risk of developing skin cancers and wrinkles. If you are Skin Type I, you will not tan no matter how long you bake in the sun. Persistent sunbathing is not only futile, but downright dangerous.
Skin Type II: These people are also fair-skinned but not as sensitive to the sun's rays as Type I individuals. They usually burn when exposed to the sun, and only occasionally develop a "weak" tan.
Skin Type III: This type includes people with darker skin who usually tan, but sometimes do develop sunburns.
Skin Type IV: These people always tan well, and almost never develop sunburns.

Depending upon the type of skin you have, there is a wide range of sunscreen products that are rated according to the degree of protection they can give against ultraviolet radiation. This rating method is known as the Sun Protection Factor (SPF) system. A product rated SPF 15 will provide 15 times the user's natural skin protection. If a person is susceptible to developing a mild sunburn after being out in the sun for one hour and applies an SPF-15 sunscreen before sunbathing, he or she should be able to lie out in the sun for 15 hours before developing his or her mild burn. SPF numbers range from 2 to 50!

I believe everyone - every skin type - should use an SPF 15 sunscreen. As far as I am concerned, the numbers higher than 15 are meaningless. An SPF-15 sunscreen will filter out 93 percent of the harmful UVB rays. This should be sufficient for most individuals. When you use any sun-tanning product, follow the directions given by the manufacturer, and reapply the product every two or three hours. Always reapply your sunscreen after swimming. The best approach to sun tanning is common sense. This large envelope that we call the skin has to last a lifetime, so give it the protection it deserves.

Tanning salons have sprung up all over the country in response to the suntanning craze. Although they are marketed as using only the "safer" long-wave ultraviolet rays (UVA), the lamps used in these salons are fraught with the same hazards as other forms of ultraviolet radiation. There are definite dangers associated with repeated exposure to UVA radiation. In addition to premature aging, wrinkles, and the potential for developing skin cancer, other harmful effects may include:

Damage to the eyes, resulting in cataracts.
Aggravation of existing skin damage caused by sun exposure.
Aggravation of "light-sensitive" skin disorders, such as cold sores and lupus erythematosus.
Damage to the thinner skin of older people.
Adverse reactions to certain soaps, toiletries, high blood pressure medications, tranquilizers, birth control pills, etc.
Changes in the immune system and in the blood vessels in the skin.

Do your skin - and yourself - a favor: stay away from those artificial tanning rays.

A note about children's skin: since children often spend many hours playing in the sun, protecting children's skin from the sun's harmful rays is one of the most important ways to pro-mote their long-term health. Always apply a sunscreen with an SPF of at least 15 to the skin of any child over the age of 6 months before the child is exposed to sunlight.

SUN POISONING

Sun poisoning is a nonscientific term that refers to a variety of sun-allergic responses. Light-skinned people, who have less protective skin pigment, are especially susceptible to sun-poisoning, but it can occur in anyone who is exposed to enough sunlight. It often occurs when sun exposure is combined with a variety of drugs, chemicals, cosmetics, and plants.

The classic example of sun poisoning is sunburn. We all know that redheads suffer more from the effects of the sun's rays than the rest of the population. This is because their skin contains less melanin pigment, which is one of the body's main defenses against sunburn. Black people rarely suffer from sunburn because the pigment in the upper layers of their skin prevents the penetration of the sunburn rays to the sensitive, deeper layers.

The use of certain common drugs can alter the skin's normal protective response to the sun in some susceptible people. Such individuals develop a severe rash with blisters from the slightest exposure to sunlight or even fluorescent light. Drugs most commonly implicated in this type of reaction are sulfa containing drugs, tetracycline and its relatives, various tranquilizers, high blood pressure medications, birth control pills, and oral medications used for diabetes and fungus infections such as ringworm.

Direct contact with certain chemicals, followed by sun exposure also can cause sun poisoning. The most common substances that cause these "sun-allergic" responses are found in deodorant bar soaps, detergents, certain suntan lotions, shampoos, "first-aid" creams, and various cosmetics and toiletries. Even chemicals found in a variety of vegetables and fruits can cause sun-sensitive reactions. Gardeners and farmers who spend time in the sun and handle foods such as carrots, celery, parsnips, figs, and limes are especially susceptible. Sun poisoning has also been reported as a result of using herbal shampoos prior to sun exposure.

The symptoms of sun allergy consist of severe itching and a rash. They typically occur a few days after the combination of the chemical substance and the light. This sensitivity can be so pronounced that a minute amount of the offending substance left on the skin, followed by exposure to even fluorescent light, may trigger a reaction.

The treatment for sun poisoning is essentially the same as for any allergic dermatitis, such as poison ivy dermatitis. If your case is mild, use wet compresses or soothing baths followed by calamine lotion to relieve your symptoms. If your itching is more persistent, take an antihistamine. For any severe reaction accompanied by intense itching and blisters that weep and ooze, see your dermatologist. You may need treatment for dehydration and possible infection.

PREVENTING SUN POISONING

Preventing sun-sensitive reactions may take a lot of trial and error to determine which drug, chemical, or plant is the culprit. Once you have discovered the causative agent, eliminate it from your routine. If the offender is a drug that is essential for your health (high blood pressure pills or antidiabetic medications for example), you will need to stay out of the sun at all times.

If you are fair-skinned, the best way to avoid a sun-sensitive reaction is to avoid the sun. If this is not possible, then tan slowly and cautiously. To prevent overexposure to the sun, use a good sunscreen. Sunscreens usually contain chemicals that selectively block out or absorb all the harmful "short" ultraviolet rays, permitting some of the longer, tanning rays to get through to the skin. A good, but cosmetically inelegant, sun-blocking preparation is zinc oxide paste. To protect the delicate areas of the lips, use a "lipstick" that contains a sun-blocking agent.

Dr Litt is an internationally known Dermatologist, who practices in Cleveland, Ohio

This article is the exclusive property of Dr. Jerome Z. Litt, M.D.
It may not be duplicated, copied, or otherwise reproduced
without his express, written permission.