|
Sun Damage
This information is not meant to replace your physician and is simply provided as
a free educational service to our visitors. If you feel that you have a skin
problem, please consult with your physician.
Sunlight permanently damages skin. Ordinary sun exposure during tanning and
outdoor sports causes permanent skin changes. These changes build up over the
years so that even moderate repeated sun exposure causes visible skin damage.
Most of the wrinkling, roughening, and freckling that appears on the face,
hands, and arms of white adults comes from sun damage, not age. You can see
this if you compare less sun-exposed areas, such as your abdomen or the
undersides of your arms, with sunexposed areas such as your face, neck or upper
surfaces of your arms. The natural coloration of your skin, pigment, protects
you from the damaging effects of sunlight. Persons with fair skin who have
little pigmentation are more prone to sun damage than dark-skinned individuals.
The skin-damaging effects of sunlight gradually lead to roughening, freckling,
and wrinkling. Many people in their 30's and 40's are unhappy because their
wrinkled, roughened, sun-damaged skin makes them appear 10 to 15 years older.
Unfortunately, there's no way to undo these changes. Young people should
realize that they'll ultimately pay a very steep price for the temporary
glamour of a deep suntan.
A more serious effect of sun damage is skin cancer. Sun damage is the chief
cause of skin cancer. Here again, fair-skinned individuals are much more
susceptible. Skin cancer rarely occurs in blacks. As you might expect, skin
cancer tends to occur on sun-exposed areas such as the face, neck, shoulders,
and arms. Skin cancers can usually be removed by minor surgery.
Ultraviolet rays - the invisible enemy
Sunlight contains both ordinary, harmless, visible light and shorter, invisible
light rays called ultraviolet light. Tanning, burning, and skin damage from
sunlight are caused by ultraviolet rays. Since ultraviolet rays produce both
tanning and skin damage, it's impossible to tan "safely" and avoid permanent
skin damage. Discussions on sunbathing that describe "safe" tanning refer to
avoidance of sunburn. By proper timing, most persons can get a deep tan without
sunburn. However, no one can get a tan without some skin damage.
Blocking out all light with clothing is most effective. Certain sun protectives
depend on the same principle. They coat the skin with a paint-like pigment that
mechanically blocks light. They work well, but they're messy and rather
unsightly.
There are also many clear sunscreens that absorb ultraviolet light. These
"clean" sunscreens contain either PABA (para-aminobenzoic acid) or a
benzophenone compound. Some of the PABA-containing sunscreens are taken up by
the skin and will provide some protection in the water provided they're applied
one or two hours before swimming. An occasional person is allergic to PABA or
its derivatives, so please try PABA-type sunscreens on a small area of skin
before spreading it all over your body. The other chemical class of sun
protectives, the benzophenones, rarely cause skin allergy. Benzophenones wash
off, however, and therefore do not protect swimmers. Some benzophenones have a
bitter taste that can be annoying when applied near the mouth.
There are many sun protectives on the market. The better ones are labeled with
a number called the sun-protective factor (SPF). The higher the SPF number, the
better the protection. The best sunscreens have an SPF of 15, and are what you
should use.
Water removes most sunscreens. Remember to put on another coat of sunscreen
after swimming or bathing. If you're sweating heavily, use some more sunscreen
every hour or two. If you're in very bright sunlight, it's wise to protect your
skin as much as possible with clothing (long sleeves, gloves, wide-brimmed
hats) and use one of the "clean" chemical sunscreens on the parts of your skin
exposed to the sun.
Protect your lips from sun damage. The darker lipstick shades are effective for
women. Men, and women who don't wear lipstick, should use an
ultraviolet-absorbing lip pomade. Women can use makeup with a sun protective.
The sun protective should be applied first, then the makeup. The makeup itself,
especially if heavily colored, provides some sun protection.
93 million miles away, there is a luminous celestial body called the sun. The
sun, which is a source of energy, without which this earth cannot function, is
a blessing to most, but a curse to others. You should aim to minimize sun
exposure, not avoid it.
Each year with the arrival of the summer solstice, June 21st to be exact, our
mixed blessing is increased with the onset of the most intense period of
sunlight to which we are all exposed.
Humans have worshiped the sun since primitive times. Little wonder was raised
to the status of the gods, for its light and warmth would bring comfort,
dispelling fear as it chased away the cold dark night.
But in modern times, sun worship has taken on a different form, that of an
uncontrolled exposure to sunlight in order to achieve a "tan".
As recently as the Victorian era, however, the opposite was a rule. Alabaster
white skin was prized and protected by long garments, broad hats, and parasols.
This was true even in the early cultures that paralleled the religious worship
of the sun. The aristrocats of Crete preserved white skin by remaining indoors
in contrast to the nut brown skin of field workers.
But the colonial British in Africa and India did not have the good sense to
avoid the sunlight-prompting the fame tune by Noel Coward, "mad dogs and
Englishmen go out in the noon day sun".
It was only recently that medical science began to recognize the harmful
effects of sunlight. It was in 1870 that dermatologists first began to
speculate about the connection between sun and skin tumors. By the turn of the
century, the famed German Jewish dermatologist, Gersham Unna, demonstrated the
length between the generation of the elastic tissue of the skin called solar
elastosis, and the development of abnormal thickenings of the skin that we call
solar or actinic keratoses, and skin cancers in sailors and farmers.
Sunscreens
The food and drug administration presently classifies sunscreens as "drugs"
intended to protect the skin against actinic or solar damage.
Solar protective preparations that can be applied to the skin are chemicals in
the form of solutions, gels, creams, or ointments that we hope will attenuate
the bad effect of sunlight due to both UVA and UVB. Protection is afforded by
the sunscreen through active ingredients that absorb, reflect, or scatter the
solar radiation that strikes the skin.
Topical sunscreens can either be chemical sunscreens or physical sunscreens.
Chemical sunscreens contain one or more ultraviolet absorbing agents that, when
applied in a thin and usually invisible film, act as a filter to diminish the
penetration of the ultraviolet to the living portion of the epidermis. The most
widely used of the sunscreens in this category contain paraaminobenzoic acid or
poppa or a derivative of poppa, centamades, benzyphanone, salicylate, and
antyelates.
Physical sunscreens on the other hand are usually opaque formulations that
contain materials that are particulate in nature. These do not selectively
absorb the ultraviolet, but rather, when applied in a thin film, primarily
reflect and scatter the ultraviolet because of the particles they contain.
These agents are titanium dioxide, talc, zinc oxide, kaolin, ichthamnol, or
pharachloride. These are usually very messy and not very cosmetically elegant.
In contrast to the chemical sunscreens, they are not easily washed off and have
the important property of sticking to the skin that is referred to as
substantiveness.
Several years ago, professor Phrons Griter of Austria proposed a concept that
is now well known in this country. He proposed a means of grading sun
protective materials that is referred to as sun protection factors.
The SPF is defined as the ratio of the least amount of ultraviolet B energy
required to produce a minimal redness reaction in skin through a sunscreen
product film to the amount of energy required to produce the same redness on
skin without any sunscreen application. As a standard for comparison, a
solution of 8% homomenthol salicylate is given the SPF of 3.5 to 4.5.
As a biological system being measured in one individual for use in another
individual, it is apparent that the values are only at ball park approximation.
Indeed there are so many factors that influence the actual performance of a
sunscreen with the same SPF that it is remarkable there is any uniformity at
all.
For more on Sun Concerns,
click here.
For more topics, click here.
|