When we speak of vital organs, we usually think of heart, lungs, and brain. When any stops functioning, we can’t survive. Another vital organ, often overlooked, is our skin. We can’t live without its protection.
Skin is the largest organ of the body, containing glands, blood vessels and nerves. Its first function is to serve as a barrier between our inner selves and atmospheric contaminants circulating in the outside world. When skin is cut, wounded, or even chapped, we are susceptible to invasion by bacteria, resulting in infection. No better case can be made for regular and appropriate cleansing of the skin. Cleansing in the morning rids the skin of the body waste materials that have accumulated during sleep. Cleansing again at night removes the collection of impurities from the atmosphere. The complexion should always be cleansed by emolliency, never soap, to guard against defatting and depletion of the barrier properties.
Skin is not impenetrable. It must allow for respirations, keeping the body temperature even. One square inch of skin may contain hundreds of sweat glands, thousands of nerve endings and receptors for perception of heat, cold, pain and tactile sensations. For these, among other reasons, skin creams must be non-comedogenic (non-pore clogging) to avoid a ‘hot house’ effect. Studies show that comedogenic products will cause unnecessary exertion of the body from obstruction of the respiratory process.
Even when it is totally unmarred, the skin is not a perfect barrier. For example, the drug scopolamine, used to fight motion sickness, can be introduced through a thin, plastic-like patch, placed behind the ear. This transdermal method of delivery can also be used for nitroglycerin given to heart patients. You don’t get efficient absorption through the skin, but you get slow, constant absorption. This steady delivery means that the drug reaches a plateau in the body and stays there; unlike the highs and lows experienced when a drug is taken orally. Transdermal absorption is the only system of delivery available for topical skin care.
Resiliency and pliancy in the skin come from the stratum corneum; the top layer of skin. When skin is hydrated, it can move and stretch. When it’s dry, it will crack. Despite the common advice to drink eight glasses of water a day, an excessive intake of fluids doesn’t seem to help hydrate the skin or combat dryness.
SKIN ANATOMY, FUNCTION, PROTECTION
A. STRUCTURE OF SKIN
The skin is divided into three layers: the epidermis, the dermis, and the subcutaneous tissue.
Epidermis: contains five strata or layers. New cells are formed in the deepest of the five layers and are continually replaced. Replacement slows with aging and sun damage. Cells migrate upward to the most superficial layer (stratum corneum) where they are shed.
Dermis: Is divided into two layers. The thin papillary dermis (thin superficial layer) and the reticular dermis (deeper, thicker layer). The dermis contains three types of tissue: Collagen, elastin, and reticular fibers; blood vessels, which supply skin nutrition; and all nerve endings, which detect sensation and temperature.
Subcutaneous tissue: The fat tissue located deep to the dermis and superficial to underlying muscle.
B. FUNCTION OF THE SKIN
Skin is a barrier between our body and harsh foreign materials in our surroundings. It protects against bacteria and infection. Skin is responsible for regulating body temperature. Skin respiration and sweating maintain body temperature within acceptable limits. Skin contains most of our sensation receptors for heat, cold, pain, and tactile (touch) sensation. One square inch of skin contains thousands of nerve endings and receptors as well as hundreds of sweat glands.
C. DAMAGE TO THE SKIN
Ultraviolet Light Exposure
Types: There are three types of ultraviolet rays, UVA, UVB, and UVC. Only UVA and UVB penetrate the atmosphere. UVC is insignificant for sun exposure.
UVA: Intensifies the effects of UVB exposure, damages the collagen and elastin in the dermis, contributing to premature wrinkling and aging (photo aging.) UVA is the primary UV wavelength used in tanning booths. There is strong evidence that UVA exposure in the tanning industry is harmful to your health.
UVB: Causes genetic cell damage, which can lead to development of skin cancer. It also causes sunburns.
The idea that ‘building a tan’ prior to summer or vacation provides protection is a myth. Effects of sunlight exposure are cumulative and the more exposure, the more damage. That damage may not be evident for 10-20 years. Ultraviolet light can activate up to 40 different diseases, and has an adverse effect on the body’s immune system. Photosensitivity reactions can occur with UV exposure. If you are taking any medications, check carefully about photosensitivity reactions that can occur with UV exposure.
Wind, Humidity, Temperature
Geographic Location: The nearer the equator (further south in the U.S.) the greater the intensity of UV exposure. At higher altitudes, UV exposure is also significantly greater.
Daily Activities: Activities outdoors increase UV exposure. Many recreational activities involve markedly increased exposure to UV, for example water sports or snow sports where reflection magnifies the exposure.
Examine your activities carefully. Even routine commuting outdoors involves sun exposure, the effects of which are cumulative over your lifetime. The relentless, cumulative every day exposure to ultraviolet radiation is much more dangerous than the occasional sunburn!
D. AGING OF THE SKIN (PHOTO AGING)
Many dermatologic experts feel that 90% of skin aging and wrinkling is due to ultraviolet radiation exposure. 80% of that exposure usually occurs before 20 years of age. UVA breaks down collagen and elastin in the dermis. This breakdown renders the skin more brittle and inelastic, contributing to dryness, cracking and disruption of skin integrity.
Generation of new cells in the deep layers of the dermis for cell replacement is slowed by UV exposure. Epidermal cell replacement also slows down with aging.
UV retards rate of cell production and blood vessel production.
- Loss of Lubrication
As dermal and epidermal sebaceous glands decrease production, the skin surface becomes drier, more brittle, and tends to crack and shed more cells. - Loss of Elasticity (Development of Elastosis)
As the skin loses elasticity, normal movements of the skin with facial or body movement produce more direct stresses resulting in breakdown in the dermis rather than the normal response of stretching and rebounding. - Stretching and Shape Distortion
If the skin does not ‘give’ with stretching and subsequently ‘rebound’, the stretching can result in breakdown of skin structures, and permanent shape or surface distortions. ‘Stretch marks’ and permanent skin laxity or looseness are examples of permanent shape distortion.
E. SKIN CANCER
Causes of Skin Cancer
- Ultraviolet Exposure
The most significant controllable factor in the development of skin cancer appears to be sun exposure.
Ultraviolet B (UVB) rays are most likely to cause genetic damage to cells, leading to skin cancer, but UVA may intensify UVB effects and therefore are also damaging. - Inherited Predisposition
People who inherit the characteristics of fair skin and light colored eyes (e.g. people of Celtic origin) are most susceptible to damaging effects of UV radiation.
Costs of Skin Cancer
- The Defect
Skin cancers can result in loss of entire facial structures such as the nose, eyelid, ear or cheeks. The cancers usually develop later in life (after age 40), but can occur much earlier. - Prices of Reconstruction
Although reconstructive techniques are available in modern plastic surgery, the procedures are expensive both monetarily, in time off work and emotionally - Permanent Compromises.
Reconstructive surgery can never restore structures to their normal state.
When it is necessary to ‘borrow’ tissue from an area to reconstruct another area, donor site defects and scars result. Where the defect is reconstructed, scars and some contour irregularities usually persist. In severe cases, loss of body function can occur in addition to the cosmetic defect.
F. PRESERVING AND CARING FOR THE SKIN
Basic Skin Care
- Cleanse/Protect/Moisturize/Rejuvenate (i.e. Exfoliate, Improve Dermis, Control Pigment).
- Nutrition, regular exercise, vitamins supplements and holistic health principles are important concepts in maintaining general health as well as skin health. Healthy skin is beautiful skin.
- Sunscreens and Sunblockers
The most effective treatment for sun damage is prevention. Chemical absorbing sun screens as well as physical sunblockers must protect against UVA and UVB rays of the sun. They must give broad spectrum protection, and be well tolerated and compatible with various skin types. Shading and avoiding the most intense mid day sun complete the triad of sun protection that is so important in maintaining good skin health.