We are all too familiar with the aging process. Young individuals with soft, smooth, and supple skin become aware, with the passage of time, of signs of aging: the development and deepening of wrinkles, the appearance of age spots, and loosening of the skin. These changes occur in all layers of the skin.
They can be classified as follows:
1. Changes due to the natural aging process: chronological aging. Skin aging is the natural expression of an individual’s age. Yet, people of identical chronological age may appear to have younger- or older-looking skin. Genetic factors have a great impact on determining skin quality over time. Genetics determines the rate at which the skin ages by controlling certain factors such as: _ skin durability, _ hormonal mechanisms, and _ skin thickness (thicker skin tends to wrinkle less).
2. Changes due to environmental factors: the leading factor here is solar radiation. These changes appear, of course, in areas of the body exposed to the sun. Prolonged exposure to cold, wind, and environmental pollutants such as smog may also cause cumulative damage to skin. The desire to preserve a youthful appearance has led to the development of a myriad of cosmetic products, marketed with labels such as “prevents skin aging” and “removes wrinkles.”
Not all of these products are based on biological reasoning that supports the advertising claims. Most “before and after” photographs reflect the photographer’s technical skill rather than the product’s effectiveness. This chapter reviews the skin-aging process, possible preventive measures, and corrective methods that have proven to be effective.
Chronological Aging
The following changes occur with the natural passage of time. They appear in all areas of the body, regardless of exposure to the sun. They include: degeneration of elastin fibers, degeneration of collagen fibers, and thinning of the skin.
Elastin Fibers
Thin, functioning elastin fibers of the skin undergo a degenerative process, gradually becoming lumps of fibers of poor quality. The changes in the elastin fibers are the major cause of the development of wrinkles and the loss of skin elasticity.
Collagen Fibers
In addition to the degeneration of elastin fibers, there is a gradual degeneration and reduction in the amount of collagen fibers. This causes a decline in skin strength, with subsequent loosening.
Thinning of the Skin
In general, starting at approximately 45 years of age, there is a gradual thinning of all skin layers, including the epidermis, dermis, and the subcutis. This process is more pronounced in women than in men. There is also a gradual flattening of the wavy attachment between the epidermis and dermis. The subcutaneous fatty layer becomes thinner. Loss of the fatty layer is more prominent in certain areas: face, hands, and calves. This process of degeneration and waning of tissue is called atrophy.
All of the above changes cause the appearance of wrinkles and loss of skin elasticity. The loss of strength and thickness in the skin, and the layers beneath it, causes it to become more vulnerable.With advancing age, there is a tendency to develop local hemorrhages as a result of minimal trauma: this is termed “easy bruisability.”
By Avi Shai, Howard I. Maibach, and Robert Baran from Handbook of Cosmetic Skin Care, 2009
