Overview of Skin Aging and Photoaging

Yolanda Rosi Helfrich, MD; Dana L. Sachs, MD; John J. Voorhees, MD

Disclosures

Dermatology Nursing. 2008;20(3):177-183. 

In This Article

Treatment of Aging Skin

Treatment of aging skin includes (a) measures to prevent against UV damage and (b) medications and procedures to reverse existing damage.

Photoprotection refers to measures that can be taken to protect the skin from UV damage and is achieved by sunscreens, sun-protective clothing, and sun avoidance. Sunscreens are broadly de fined as agents that protect against UV damage and protect against sunburn, wrinkles, and pigmentary changes (Gilchrest, 1996). Sun-protection factor (SPF) refers to the degree of protection from ultraviolet B and does not account for protection against ultraviolet A. Patients should be advised to choose a sunscreen with an SPF of 15 or higher and to apply liberally and frequently to all exposed body sites, especially the face and neck. Sunscreens should be applied every 2 to 3 hours, especially if patients are engaged in outdoor activities. Because the SPF rating only confers protection against ultraviolet B, patients should be educated to look for ultraviolet A protection features in a sunscreen. Chemical blockers of UVA include oxybenzone and avobenzone (Parsol 1789). Some newer UVA blockers have become available in the United States including ecamsule, which is the most photostable UVA blocker available and sold under the trade name Mexoryl[99] (Anthelios, La Roche Posay/L'Oreal), and Helioplex,[99] a stabilized form of avobenzone (Neutrogena). Sun screens that contain physical blockers such as titanium dioxide and zinc oxide confer protection against both UVB and UVA. Newer technologies such as micronization have been developed over recent years to make these physical blockers more cosmetically acceptable. A complete list of sunscreens with the Skin Cancer Foundation's Seal of Recommendation can be found at www.skincancer.org.

Sun-protective clothing lines exist and are widely available in sporting goods stores and on the Internet. These clothing lines provide hats, long-sleeved clothing, etc. and are geared towards patients who work outdoors and are avid outdoor enthusiasts for whom sunscreens might be less practical to use. The fabrics used in these lines are highly engineered and sophisticated materials that confer high levels of sun protection and protect against both UVA and UVB. Solumbra, manufactured by Sun Precautions, offers an SPF 30+ and reportedly blocks 97% of UVA and UVB. Coolibar is another brand of sun-protective clothing and hats and offers an ultraviolet protection factor (UPF) of 50+ and reportedly blocks 98% of ultraviolet A and B. UPFs are similar to SPFs but are typically used for devices such as clothing and fabrics rather than for sunscreen. Clothing lines and other sun-protective devices endorsed by the Skin Cancer Foundation are listed on their Web site.

Finally, sun-protective behavior is achieved through patient education. Patients should be discouraged from using suntanning beds, which accelerate photoaging. Patients should be educated to avoid midday sun exposure when ultraviolet radiation is most intense, to participate in outdoor activities early or late in the day, to avoid sunbathing (even with sunscreens), and to seek shady, covered areas rather than direct sunlight.

Available topical retinoids include prescription tretinoin (Retin-A®), adapalene (Differ en®), and tazarotene (Tazorac®) and over-the-counter Retinol® and Ret in ol-A®. These drugs are derivatives of vitamin A which have anti-aging properties. Topical tretinoin was first observed to ameliorate the clinical signs of photoaging by Cordero (1983) and Kligman, Grove, Hirose, and Leyden (1986). The first double-blinded, randomized, vehicle-controlled clinical trials investigating the use of tretinoin for photoaged skin were performed in the late 1980s. In these studies, investigators found that surface roughness, dyspigmentation, and fine wrinkles demonstrated the most improvement with topical tretinoin therapy in the first 4 to 10 months of therapy (Weiss et al., 1988). Because epidermal changes seen early in therapy reverted to baseline, the wrinkle-improving effect of tretinoin was presumed to be due to effects on the dermis. In studies, topical tretinoin increased collagen type I in photoaged skin (Griffiths et al., 1993; Talwar, Griffiths, Fisher, Hamilton, & Voorhees, 1995). It is common and predictable for patients to develop a retinoid dermatitis characterized by erythema and scaling after starting a retinoid. With time and continued use, this dermatitis improves. A patient may use topical tretinoin as part of a daily and ongoing program to reverse the signs of clinical photoaging. Topical tretinoin is typically prescribed as a 0.05% or 0.1% cream, and for patients more sensitive to the effects, lower strengths can be used (0.02%, 0.025%). Tretinoin can be used indefinitely. There are no true contraindications to its use, though some patients are not able to tolerate the accompanying retinoid dermatitis.

Cosmeceuticals are agents that are marketed as cosmetic products, contain biologically active ingredients, and are available without a prescription. Drugs exert a biologic effect, are dispensed by prescription, and are regulated by the U.S. Food and Drug Administration. Cosmeceuticals do not undergo the rigorous testing required for drug approval, and there are few clinical controlled trials of these products. In fact, most of the work supporting their use is in vitro or small, open-label, industry-sponsored trials. The cosmeceutical industry is huge and future projections estimate that it will exceed $16 billion by 2010 (Choi & Berson, 2006). Cosmetic products containing peptides, antioxidants, and botanicals are examples of cosmeceuticals. A complete review of cosmeceuticals is beyond the scope of this article, so only select ones will be mentioned.

Peptides are amino acid chains that are fragments of large proteins such as collagen. Pal-KTTS is a collagen peptide fragment, and there is evidence in wound healing that it may penetrate into the dermis and stimulate collagen production (Katayama, Armendariz-Borunda, Raghow, Kang, & Seyer, 1993). Pal-KTTS is marketed as Matrixyl[99] (Sederna, France) and is an ingredient in a number of cosmeceuticals. A tripeptide-copper complex can increase collagen in wounds and is an ingredient in a number of cosmeceuticals such as Procyte GHK-copper peptide (Maquart et al., 1993).

Antioxidants are molecules that work in the skin to reduce ROS, which are generated by UV damage and lead to breakdown of collagen. There is much interest in the use of antioxidants both orally and topically to combat aging skin, but there are few published studies on the efficacy of these agents. There is reason to be optimistic, as preliminary studies demonstrate that certain antioxidants may exert an anti-aging effect by preventing and even reversing sun damage. Idebenone is a synthetic analog of Coenzyme Q 10 with potent antioxidant activity; it reduces skin roughness, increases skin hydration, reduces fine lines, and was associated with an improvement in overall global assessment of photoaged skin (McDaniel, Neudecker, DiNardo, Lewis, & Maibach, 2005). Topical vitamin C 5% cream applied for 6 months led to clinical improvement in the appearance of photoaged skin with regard to firmness, smoothness, and dryness compared to vehicle (Humbert et al., 2003). Topical vitamin C stimulates the collagen-producing activity of the dermis (Nusgens, Humbert, Rougier, Richard, & LapiE8re, 2002).

Botulinum toxin and soft tissue fillers. Purified botulinum toxin type A (Botox®, Allergan Inc., Irvine, CA) is a neurotoxin used to paralyze various muscle groups of the face for cosmetic improvement of wrinkles. Injection of Botox® is easily one of the most popular procedures for aesthetic enhancement. Botox® is most commonly used to treat wrinkles of the glabella, forehead, and periocular regions. Paralysis of these small muscle groups of the face results in a more youthful appearance. With time and repeated injections, many patients will note softening or disappearance of particular facial lines. Botox® works by neuromuscular inhibition of acetylcholine and the effects last from 3 to 6 months. Side effects of Botox® injections include pain, bruising, and paralysis of the nerves that control eyelid function.

Of the 9.7 million nonsurgical procedures performed in the United States in 2004, nearly 10% were soft tissue augmentation procedures, as reported by the American Society for Aesthetic Plastic Surgery (Matarasso, Carruthers, Jewell, & The Restylane Consensus Group, 2006). First approved in 1981, bovine collagen was the gold standard for soft tissue augmentation, but in recent years, non-animal stabilized hyaluronic acid gel marketed as Restylane® (Medicis Pharmaceuticals, Scottsdale, AZ ) has gained tremendous popularity among patients and physicians, and is currently the most widely used filler in the United States and Canada (Coleman & Carruthers, 2006). Other available fillers include calcium hydoxylapatite (Radiesse®, BioForm Medical, Inc., San Mateo, CA), poly-L-lactic acid (Sculptra,[99] Dermik Laboratories, Bridgewater, NJ), and human-based collagen (Cosmoderm® and Cosmoplast®, both made by Allergan Inc., Irvine, CA). Soft tissue fillers are most commonly used to improve the appearance of the nasolabial folds, which become more pronounced as a result of photoaging and chronological aging. They are also injected into cheeks, periocular areas, and glabellar lines, and are often used in combination with Botox® for maximal effect, since they address different aspects of aging skin (Coleman & Carruthers, 2006). Soft tissue fillers have been thought to exert their effect by volume expansion, but recent work investigating the mechanism of action of Restylane® suggests the filler stretches fibroblasts, leading to new collagen formation (Wang et al., 2007).

Laser procedures for the aging face are numerous and emerging rapidly. A complete discussion of these is outside the realm of this article.

Ablative laser resurfacing is considered to be the gold standard to improve clinical features of the aging face and generally refers to treatment with a carbon dioxide laser (10,600 nm). It improves fine and some coarse wrinkles and overall dyspigmentation, lightens dark under-eye circles, and generally improves the texture of skin; it can also be used to ameliorate old acne scarring. This procedure works by vaporizing the epidermis and portions of the papillary dermis so that neocollagenesis can occur (Railan & Kilmer, 2005).

The biochemical changes associated with the carbon dioxide laser have been studied; a well-organized wound healing response occurs, resulting in quantitatively significant increases in production of types I and III procollagen (Orringer et al., 2004). Due to the depth of penetration of this laser, anesthesia is required and can be achieved by IV sedation, endotracheal sedation, or a combination of oral anxiolytics, topical EMLA, and regional nerve blocks. Carbon dioxide laser resurfacing is performed as a single treatment, and it takes 2 weeks for the skin to re-epithelialize following the procedure. Antiviral prophylaxis is started 1 day prior to the procedure and continued for 14 days, and anti-staphylococcal antibiotics are started 1 day prior and continued for 7 days. During this time, wound care is frequent and time consuming, and patients must be monitored closely for viral and bacterial skin infections. Patients with Fitzpatrick skin types I and II are the ideal candidates, as the procedure is associated with skin lightening. Additionally, patients may retain a pink or erythematous tone to their skin that may last for weeks to months following the procedure.

At our institution, an occlusive protective dressing is left in place for 48 hours. Once the dressing is removed, the skin is cleansed with a diluted vinegar solution and a copious layer of Aquaphor® Healing Ointment or Vaseline® is used to cover the resurfaced skin. Patients need to perform dilute vinegar soaks for 7 to 14 days every 2 to 3 hours during the day and through the night followed by Aquaphor or Vaseline application until the skin is completely re-epithelialized.

Non-ablative laser resurfacing procedures are much less invasive than ablative lasers. There is much interest in these techniques because of the intense wound care, high cost, and recovery time immediately associated with ablative laser resurfacing. Select non-ablative lasers include the long-pulsed neodymium YAG (1064 nm), 1320 nm (CoolTouch®, Roseville, CA), radiofrequency (Therm age®, Thermage, Inc, Hayward, CA), and Fraxel® (Reliant Technologies, Mountainview, CA). Each of these treatments is performed on multiple occasions, usually several weeks apart. It is important to bear in mind that none of the non-ablative lasers can replace the ablative procedures.

Intense pulsed light is another light-based treatment but is not a true laser as it is composed of several different wavelengths. It is popular for facial rejuvenation and is used to lighten lentigines and reduce telangiectases to achieve an overall blending effect. When used with a photosensitizer (photodynamic therapy), intense pulsed light and other light-based therapies may have a greater effect than the light source alone (Dover, Bhatia, Stewart, & Arndt, 2005). Q-switched lasers are lasers that target pigment in skin and are useful for removing benign pigmented lesions seen in photoaged and aged skin. Careful clinical assessment is required prior to proceeding with treatment to avoid laser treatment of potentially malignant skin lesions such as lentigo maligna or melanoma. Pulsed-dye lasers and KTP lasers are used in photoaging to target the dilated blood vessels which produce a ruddy and uneven appearance. Treatment with either of these vascular lasers usually requires several treatments. Side effects include increased erythema immediately following the treatment, slight discomfort, swelling, and potential bruising.

Pre-treatment clinical assessment and consultation are critical before prescribing or performing the previously described treatments and procedures to review the risks and complications. Patient expectations must be gauged so that optimal improvement is achieved. It is of utmost importance that patients follow wound care instructions after ablative resurfacing in order to achieve optimal healing. It is also crucial that patients understand that textural irregularities and dyspigmentation of skin can be improved, and that there will be a tightening effect, but that the results will not simulate a surgical facelift.

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