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Skin
Wrinkles
As a person ages, the
skin undergoes significant changes:
- The cells divide
more slowly, and the inner layer of skin (the dermis) starts to thin.
Fat cells beneath the dermis begin to atrophy (diminish). In addition,
the ability of the skin to repair itself diminishes with age, so
wounds are slower to heal. The thinning skin becomes vulnerable to
injuries and damage.
- The underlying
network of elastin and collagen fibers, which provides scaffolding for
the surface skin layers, loosens and unravels. Skin then loses its
elasticity. When pressed, it no longer springs back to its initial
position but instead sags and forms furrows.
- The sweat- and
oil-secreting glands atrophy, depriving the skin of their protective
water-lipid emulsions. The skin's ability to retain moisture then
diminishes and it becomes dry and scaly.
- Frown lines
(those between the eyebrows) and crow's feet (lines that radiate from
the corners of the eyes) appear to develop because of permanent small
muscle contractions. Habitual facial expressions also form
characteristic lines.
- Gravity
exacerbates the situation, contributing to the formation of jowls and
drooping eyelids. (Eyebrows, surprisingly, move up as a person ages,
possibly because of forehead wrinkles.)
- Wrinkles can have
a profound impact on self-esteem. Indeed, the stigma attached to
looking old is evidenced by the fact that Americans spend more than
$12 billion each year on cosmetics to camouflage the signs of aging.
Our current society places a premium on youthfulness, and age
discrimination in the workplace, although illegal, has stalled many a
person’s career. Indeed, the emotional ramifications of aging
explain in large part why the cosmetics industry and plastic surgeons
thrive.
Aging
Process and Wrinkles: As a person ages, skin undergoes
significant changes:
- The cells divide
more slowly, and the inner layer of skin (the dermis) starts to
thin.
- Fat cells beneath
the dermis begin to atrophy (diminish).
- The underlying
network of elastin and collagen fibers, which provides scaffolding for
the surface layers, loosens and unravels.
- Skin loses its
elasticity. When pressed, it no longer springs back to its initial
position but instead sags and forms furrows.
- The sweat- and
oil-secreting glands atrophy, depriving the skin of their protective
water-lipid emulsions. The skin's ability to retain moisture then
diminishes and it becomes dry and scaly.
- Frown lines
(those between the eyebrows) and crow's feet (lines that radiate from
the corners of the eyes) appear to develop because of permanent small
muscle contractions. Habitual facial expressions also form
characteristic lines.
- Gravity
exacerbates the situation, contributing to the formation of jowls and
drooping eyelids. (Eyebrows, surprisingly, move up as a person ages,
possibly because of forehead wrinkles.)
- In addition, the
ability of the skin to repair itself diminishes with age, so wounds
are slower to heal.
Sun Damage (Photoaging)
and Wrinkles:
The role of the sun
cannot be overestimated as the most important cause of prematurely aging
skin (called photoaging) and skin cancers. Overall, exposure to
ultraviolet (referred to as UVA or UVB) radiation emanating from sunlight
accounts for about 90% of the symptoms of premature skin aging, and most
of these effects occur by age 20.
Processes Leading
to Wrinkles. Even small amounts of UV radiation trigger the
following process that negatively effects skin:
- Sunlight damages collagen
fibers (the major structural protein in the skin) and causes
accumulation of abnormal elastin (the protein that causes
tissue to stretch).
- In response to
this sun-induced elastin accumulation, large amounts of enzymes called
metalloproteinases are produced. (One study indicated that when
people with light to moderate skin color are exposed to sunlight for
just five to 15 minutes, metalloproteinases remain elevated for about
a week.)
- The normal
function of these metalloproteinases is generally positive, to
remodel the sun-injured tissue by manufacturing and reforming
collagen. (They may even have factors that protect against melanoma,
although this is not clear.)
- This is an
imperfect process, however, and some of these enzymes actually degrade
collagen. The result is an uneven formation ( matrix) of
disorganized collagen fibers called solar scars .
- Repetition of
this imperfect skin rebuilding over and over again causes wrinkles.
- UV radiation also
promotes oxidation, the release of damaging and unstable oxygen-free
radicals. Oxidation contributes to wrinkling, possibly by activating
the metalloproteinases that degrade connective tissue.
Other
Factors Responsible for Wrinkles
In addition to
sunlight, other factors may hasten the formation of wrinkles:
- Cigarette smoke
produces oxygen-free radicals and is known to accelerate wrinkles and
aging skin disorders. A 2001 study also found that smokers have
considerably higher levels of metalloproteinases than non-smokers,
which may help account for the skin-aging effects of smoking.
- Air pollution.
Ozone, a common air pollutant, may be a particular problem for the
skin. One study reported that it might deplete the amount of vitamin E
in the skin; this vitamin is an important anti oxidant.
- Rapid weight loss
can also cause wrinkles by reducing the volume of fat cells that
cushion the face. This not only makes a person look gaunt, but can
cause the skin to sag.
Skin Types:
Experts have devised a
classification system for skin phototypes (SPTs) based on the sensitivity
to sunlight. It ranges from SPT I (lightest skin plus other factors) to IV
(darkest skin). [ See Table ] People with skin types I and II are
at highest risk for photoaging skin diseases, including cancer. It should
be noted, however, that premature aging from sunlight can affect people of
all skin shades.
Eczema
What’s
the difference between eczema and atopic dermatitis?
Eczema is a general term encompassing various inflamed skin
conditions. One of the most common forms of eczema is atopic dermatitis (or
"atopic eczema"). Approximately 10 percent to 20 percent of the
world population is affected by this chronic, relapsing, and very itchy rash
at some point during childhood. Fortunately, many children with eczema find
that the disease clears and often disappears with age.
In
general, atopic dermatitis will come and go, often based on external
factors. Although its cause is unknown, the condition appears to be an
abnormal response of the body’s immune system. In people with eczema, the
inflammatory response to irritating substances overacts, causing itching and
scratching. Eczema is not contagious and, like many diseases, currently
cannot be cured. However, for most patients the condition may be managed
well with treatment and avoidance of triggers.
What
does eczema look and feel like?
Although eczema may look different from person to person, it
is most often characterized by dry, red, extremely itchy patches on the
skin. Eczema is sometimes referred to as "the itch that rashes,"
since the itch, when scratched, results in the appearance of the rash.
Eczema
can occur on just about any part of the body; however, in infants, eczema
typically occurs on the forehead, cheeks, forearms, legs, scalp, and neck.
In children and adults, eczema typically occurs on the face, neck, and the
insides of the elbows, knees, and ankles. In some people, eczema may
"bubble up" and ooze. In others, the condition may appear more
scaly, dry, and red. Chronic scratching causes the skin to take on a
leathery texture because the skin thickens (lichenification).
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