Causes for aging wrinkles Development of facial wrinkles is a kind of
fibrosis of the skin. Misrepair-accumulation aging theory suggests that wrinkles develop from incorrect repairs of injured elastic fibers and collagen fibers. Repeated extensions and compressions of the skin cause repeated injuries of extracellular fibers in derma. During the repairing process, some of the broken elastic fibers and collagen fibers are not regenerated and restored but replaced by altered fibers. When an elastic fiber is broken in an extended state, it may be replaced by a "long" collagen fiber. Accumulation of "long" collagen fibers makes part of the skin looser and stiffer, and as a consequence, a big fold of skin appears. When a "long" collagen is broken in a compressed state, it may be replaced by a "short" collagen fiber. The "shorter" collagen fibers will restrict the extension of "longer" fibers, and make the "long" fibers in a folding state permanently. A small fold, namely a permanent wrinkle, then appears.
Sleep wrinkles Sleep wrinkles, also known as
sleep lines or
sleep creases, are facial wrinkles that form primarily from repeated mechanical compression, shear forces, and distortion of facial skin during sleep, especially in side or stomach sleeping positions. Unlike dynamic wrinkles caused by repeated facial muscle contractions (e.g., frown lines or crow's feet), sleep wrinkles result from external forces such as sustained pressure against a pillow surface and positional shifts that create lateral drag or folding of the skin. These forces can lead to temporary creases that become more permanent over time due to cumulative mechanical stress, reduced skin elasticity with aging, and potential disruption of collagen and elastic fibers in the dermis. Dermatologists note that reducing friction does not reverse existing wrinkles but may help mitigate an environmental contributor. Customization options include tailored fits for sleep positions, such as curved designs for side sleepers to reduce fabric movement or standard shapes for back sleepers to ensure stability. Independent lab testing on some low-friction textiles (e.g., ASTM D1894) reports very low coefficients of friction, supporting reduced shear potential, though direct clinical evidence for wrinkle prevention remains limited and observational.
Water-immersion wrinkling The wrinkles that occur in skin over prolonged exposure to water are sometimes referred to as
pruney fingers or water aging. This is a temporary
skin condition where the skin on the palms of the hand or feet becomes wrinkly. This wrinkling response may have imparted an evolutionary benefit by providing improved traction in wet conditions, and a better grasp of wet objects. These results were called into question by a 2014 study that failed to reproduce any improvement of handling wet objects with wrinkled fingertips. However, a 2021 study of gripping efficiency found that wrinkles decreased the force required to grip wet objects by 20%, supporting the traction hypothesis. Prior to a 1935 study, the common explanation was based on water absorption in the
keratin-laden
epithelial skin when immersed in water, causing the skin to expand and resulting in a larger surface area, forcing it to wrinkle. Usually the tips of the fingers and toes are the first to wrinkle because of a thicker layer of keratin and an absence of hairs which secrete the protective oil called
sebum. In the 1935 study, however, Lewis and Pickering were studying patients with
palsy of the
median nerve when they discovered that skin wrinkling did not occur in the areas of the patients' skin normally innervated by the damaged nerve. This suggested that the nervous system plays an essential role in wrinkling, so the phenomenon could not be entirely explained simply by water absorption. Recent research shows that wrinkling is related to
vasoconstriction. Water probably initiates the wrinkling process by altering the balance of
electrolytes in the skin as it diffuses into the hands and soles via their many sweat ducts. This could alter the stability of the membranes of the many neurons that synapse on the many blood vessels underneath skin, causing them to fire more rapidly. Increased neuronal firing causes blood vessels to constrict, decreasing the amount of fluid underneath the skin. This decrease in fluid would cause a decrease in tension, causing the skin to become wrinkly. This insight resulted in bedside tests for nerve damage and vasoconstriction. Wrinkling is often scored with immersion of the hands for 30 minutes in water or
EMLA cream with measurements steps of 5 minutes, and counting the number of visible wrinkles in time. Not all healthy persons have finger wrinkling after immersion, so it would be safe to say that sympathetic function is preserved if finger wrinkling after immersion in water is observed, but if the fingers emerge smooth it cannot be assumed that there is a lesion to the autonomic supply or to the peripheral nerves of the hand.
Other animals with wrinkles Examples of wrinkles can be found in various animal species that grow loose, excess skin, particularly when they are young. Several breeds of
dog, such as the
Pug and the
Shar Pei, have been bred to exaggerate this trait. In dogs bred for
fighting, this is the result of selection for loose skin, which confers a protective advantage.
Techniques for reducing the appearance of aging wrinkles Retinoids Retinoids, a class of natural and synthetic
vitamin A analogues, are widely utilized for their anti-aging effects, specifically in the reduction of facial wrinkles and fine lines.
Tretinoin (Retin-A) and
tazarotene (Tazorac) are the only topical retinoids approved as medical agents for the treatment of wrinkles and fine lines from photodamage. Other retinoids, such as
retinol,
retinaldehyde, and
retinyl palmitate, are commonly found in over-the-counter
cosmeceuticals and have some evidence for reducing wrinkles and fine lines but are regulated as cosmetics rather than medicines. Dysport, manufactured by Ipsen, received
FDA approval and is now used to treat cervical dystonia as well as glabellar lines in adults. In 2010, another form of botulinum toxin, one free of complexing proteins, became available to Americans. Xeomin received FDA approval for medical indications in 2010 and cosmetic indications in 2011.
Photorejuvenation Laser resurfacing is an FDA-cleared skin resurfacing procedure in which lasers are used to improve the condition of the skin. Two types of lasers are used to reduce the appearance of fine lines and wrinkles on the face;
laser ablation, which removes thin layers of skin, and nonablative lasers that stimulate
collagen production. Nonablative lasers are less effective than ablative ones, but they are less invasive, and recovery time is short. After the procedure people experience temporary redness, itching and swelling. == See also ==