Wrinkle
A fold or crease in skin from aging or water immersion.
A wrinkle, or rhytid, is a fold, ridge, or crease that appears on a normally smooth surface, like skin or fabric. On skin, wrinkles often develop due to aging processes such as glycation, sleeping positions, loss of body mass, and sun damage, or they can occur temporarily after long exposure to water. Factors that encourage age-related wrinkling include habitual facial expressions, aging itself, sun exposure, smoking, poor hydration, and other influences. Some prevention is possible by limiting sun exposure and through diet, including carotenoids, tocopherols, flavonoids, vitamins A, C, D, and E, essential omega-3 fatty acids, certain proteins, and lactobacilli.
Facial wrinkles form through a type of skin fibrosis. According to the misrepair-accumulation theory, wrinkles arise from incorrect repairs of injured elastic and collagen fibers. Repeated stretching and compressing of the skin damages extracellular fibers in the dermis. During repair, some broken elastic and collagen fibers are not restored but replaced by altered fibers. If an elastic fiber breaks while extended, it may be replaced by a "long" collagen fiber. The buildup of these long fibers makes skin looser and stiffer, leading to a large fold. If a long collagen fiber breaks while compressed, it may be replaced by a "short" collagen fiber. These short fibers restrict the extension of longer ones, keeping them permanently folded, which creates a small, lasting wrinkle.
Wrinkling from water immersion, sometimes called pruney fingers or water immersion wrinkling, and in an old Wiltshire dialect, quobbled, is a temporary condition affecting the palms and soles. This response may have evolved to improve traction in wet conditions and grip on wet objects, though a 2014 study failed to replicate this benefit. However, a 2021 study found that wrinkles reduced the force needed to grip wet objects by 20%, supporting the traction idea. Before 1935, the common explanation was that water absorbed into the keratin-rich epithelial skin caused expansion and wrinkling, with fingertips and toes wrinkling first due to thicker keratin and lack of hair to secrete protective sebum. In 1935, Lewis and Pickering studied patients with median nerve palsy and found that skin wrinkling did not occur in areas innervated by the damaged nerve, indicating the nervous system’s essential role.
- Field
- Dermatology, Gerontology
- Known for
- Age-related skin folds, water-immersion wrinkling, and cosmetic treatments
- Causes
- Aging, sun damage, smoking, poor hydration, habitual expressions
- Treatments
- Retinoids (tretinoin is FDA-approved for photodamage wrinkles), glycosaminoglycans, injectable fillers, neuromodulators, laser resurfacing
Lore & Background
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.
Reader's Guide
Wrinkles are significant as a universal sign of human aging and as a subject of both medical and cosmetic study. The source article details two primary types: age-related wrinkles, caused by cumulative damage and misrepair of collagen and elastic fibers, and temporary water-immersion wrinkles, which involve the nervous system and vasoconstriction. A 1935 study by Lewis and Pickering showed that nerve damage prevents wrinkling, leading to bedside tests for nerve function. Treatments range from topical retinoids and glycosaminoglycans to injectable fillers, neuromodulators like Botox, and laser resurfacing. The article notes that not all healthy individuals wrinkle after water immersion, so absence of wrinkling does not necessarily indicate nerve damage. Wrinkles also appear in other animals, such as dogs bred for loose skin like the Pug and Shar Pei, where loose skin provided a protective advantage in fighting. The legacy of wrinkle research includes improved understanding of skin biology, nerve function testing, and a multi-billion-dollar cosmetic industry focused on reducing their appearance.
Did You Know?
- The Wiltshire dialect term for water-immersion wrinkling is 'quobbled'.
- A 2021 study found that water-induced wrinkles decreased the force required to grip wet objects by 20%.
- Retinoids like tretinoin and tazarotene are the only topical retinoids approved as medical agents for treating wrinkles from photodamage.
- In dogs bred for fighting, loose skin that wrinkles was selected for its protective advantage.
Frequently Asked Questions
What exactly is a wrinkle (rhytid)?
A wrinkle is a fold, ridge, or crease that appears on skin that would otherwise be smooth. It can be a permanent feature of the aging process or a temporary one triggered by prolonged water immersion.
What causes wrinkles to develop?
Wrinkles form through a mix of natural aging, repeated sun damage, smoking, poor hydration, and habitual facial expressions. Biochemical processes such as glycation further break down the structural proteins that keep skin supple.
Why do fingers and toes wrinkle after soaking in water?
Extended immersion causes the outermost skin layer to absorb water and swell, producing visible folds. This is a short-lived, fully reversible response that is mechanistically distinct from age-related wrinkling.
What medical treatments exist for wrinkles?
Dermatologists offer options including topical retinoids (tretinoin is FDA-approved for photodamage-related wrinkles), injectable fillers, neuromodulators, and laser resurfacing. Glycosaminoglycans are also used in some regimens to support the skin's structural matrix.
Can you slow down or prevent wrinkles from forming?
Limiting UV exposure and eating a diet rich in carotenoids, tocopherols, flavonoids, and vitamins A, C, and D can reduce the rate at which wrinkles appear. Staying well-hydrated and avoiding tobacco also help preserve skin elasticity over time.
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