Topical Therapy of Benign Photodamaged Skin
Sunscreens, both physical (titanium dioxide, zinc oxide) and chemical (UVA and UVB absorbent sunscreens) prevent further photoaging and malignancies associated with photoaged skin (i.e., Bowen's Disease [Figure 6]). It is important to use sunscreen with an SPF of 15 or higher to decrease the risk of basal cell carcinoma and other cutaneous malignancies.
Botanical agents can be used to treat mild forms of sun-damaged skin and include anti-inflammatories (ginkgo biloba, green tea, allantoin, aloe vera, echinacea) and antioxidants (flavonoids, carotenoids, and polyphenols). These agents enhance fibroblast proliferation, improve cutaneous microcirculation, decrease erythema and edema, and enhance antioxidant reduction of oxygen free radicals.[3,4,5,6,7,8,9,10,11,12,13,14,15] Many of these agents have been studied extensively using human skin in vitro and in vivo, although several case reports support their use in preventing and reducing photoaging.[16,17,18] Two types of antioxidants are available: enzymatic and nonenzymatic. The nonenzymatic type (e.g., vitamin C, alpha-tocopherol, retinol, beta-carotene, and glutathione) reduce the potential for cellular oxidative damage by acting as free-radical scavengers. Enzymatic antioxidants (superoxide dismutase, catalase, G-6PD, glutathione peroxidase) protect the keratinocyte by enzymatically hastening biochemical reactions.[5,6,7,8,9,20,21,22,23]
Hydroxy acids are used as exfoliants in skin care of sun-damaged skin. Examples of hydroxy acids include glycolic acid peels and salicylic acid facial peels. Clinically there is improvement of skin colour, brightness, tone, and firmness of the skin. As well, these products can decrease fine wrinkles and dyspigmentation.[24,25,26,27,28,29,30,31,32]
Multiple vitamins have been used topically for treatment of aged skin. Vitamin A derivatives (tazarotene, tretinoin) act as humectants, improving epidermal water content as well as having antioxidant properties. Vitamin A derivatives can reduce the number and severity of solar lentigos and actinic keratosis, with improved immune function of the epidermis.[33,34,35,36]
Vitamin C is also used topically for antioxidant properties and enhanced collagen production in wound healing.[6,8,9,11,16,18,37] Although vitamin E is used extensively in topical preparations as an antioxidant, it offers no photoprotective effects and has potential side effects, including allergic contact dermatitis.
Nicotinamide may have beneficial antitumour effects with suppression of UVB photocarcinogenesis.[39,40,41] Other vitamins commonly in use for therapy of photoaged skin include essential fatty acids, coenzyme Q10 (ubiquinone), dimethylaminoethanol, aminopeptides, alpha-tocopherol, and alpha-lipoic acid.[34,42,43] Total soy lotion showed significant improvement in solar lentigines, mottled hyperpigmentation, fine wrinkling, surface roughness sallowness, and overall skin damage in several small studies.[44,45] Case reports support use of these agents in skin rejuvenation of photodamaged skin, although most studies have dealt with murine skin models and human keratinocytes in vitro.
Geriatrics and Aging. 2006;9(7):494-498. © 2006 1453987 Ontario, Ltd.
Cite this: Nonmalignant Photodamage - Medscape - Jul 01, 2006.