Of Photoaging

Photoaging and photodamage are serious medical problems, not just cosmetic or aesthetic concerns, because prevention of photoaging and photodamage may prevent the progression of changes toward skin cancer. 

Drug treatment of photoaged skin can be categorized as antioxidants, a-hydroxy acids and topical retinoids. Of these three approaches only topical retinoids, particularly retinaldehyde and alWrans-retinoic acid, have a well documented ability to restorethe repair... 

Kligman D, Kligman AM (1998) Salicylic acid peels for the treatment of photoaging. Dermatol Surg 24 ... 

A new combination formulation containing hydroquinone 4%, tretinoin. 05% and fluocino-lone. 01% was approved in the United States for treatment of melasma. This combination has been approved for use in South America, Singapore, Korea, and Mexico. The formulation was based on the KligmanAVillis formula [44]. In addition, other new hydroquinone formulations contain 4% hydroquinone plus retinol in concentrations of 0.15 or 0.3%. These formulations also improve the dyschromia of photoaging. 

Spencer JM (2004) Premalignant manifestations of photoaging actinic keratoses and atypical nevi. In Goldberg DJ (ed) Photodamaged skin. Marcel Dekker, Inc., New York, pp 1-16... 

Griffiths CE, Kang S, Ellis CN, Kim KJ, Finkel LJ, Ortiz-Ferrer LC, White GM, Hamilton TA,Voorhees JJ (1995) IVvo concentrations of topical tretinoin (retinoic acid) cause similar improvement of photoaging but different degrees of irritation. A double-blind, vehicle-controlled comparison of 0.1% and 0.025% tretinoin creams. Arch Dermatol 131 1037-1044... 

Newman N, Newman A, Moy LS, Babapour R, Harris AG, Moy RL (1996) Clinical improvement of photoaged skin with 50% glycolic acid. A douhle-blind vehicle-controlled study. Dermatol Surg 22 455-460... 

Stefanaki C, Stratigos A, Katsambas A. (2005) Topical retinoids in the treatment of photoaging. J Cosmet Dermatol 4 130-134. 

Figure 10.12 Chain scission in polyethylene oxide) matrix, (a) Carbonyl region of photoaged PEO samples irradiated at lOOmWcnr2 and 75°C for various times (0, 1,2 and 4 minutes). The main band at 1725cm-1 is attributed to formate functions, whereas the shoulder at 1 750cm"1 is assigned to esters, (b) Evolution of the storage modulus (G ), the loss modulus (G"), and the tangent of the phase angle tan(8) versus time (temperature 90°C). The increase in tan(8) is evidence of chain scission, (c) Endotherms of the fusion of PEOs samples recorded at...

Bergfeld, W. et al., Improving the cosmetic appearance of photoaged skin with glycolic acid, J. Am. Acad. Dermatol., 36, 1011, 1997. 

Lundin, A., Berne, B., and Michaeelsson, G., Topical retinoic acid treatment of photoaged skin its effects on hyaluronan distribution in epidermis and on hyaluronan and retinoic acid in suction blister fluid, Acta Derm. Venere., 72, 423, 1992. 

Additionally there has been an increasing interest in the role of vitamins, especially the antioxidant vitamins, vitamins C and E, and the carotenoids in protection from ultraviolet (UV)- or chemically-induced oxidative stress as well as in the prevention and treatment of photoaged skin. UVB radiation (280 to 320 nm) is mostly absorbed in the epidermis, can directly damage DNA, and... 

There are various accelerated light stability test methods available and/or exposure in harsher climates (Florida, Arizona) to test the weathering performance. The prediction of photoageing stability based on accelerated laboratory testing is very difficult, but some attempts have been made for PVC-P (445). The most relevant point is to use as reference a formulation known to have good outdoor weathering performance. 

People who use tretinoin often report that their skin is more sensitive to the sun and burns more easily. This photosensitization is better explained by the thinning of the stratum corneum rather than by a photochemical reaction between the tretinoin and the sun s rays. It is therefore essential to recommend the use of a sunscreen (SPF 25-50 UVA + UVB + HSP induction) to patients being treated with tretinoin. It should also be borne in mind that there is a potential risk of skin cancers developing as a result of the stratum corneum thinning and the enhanced penetration of the sun s rays. Nevertheless, it appears that patients on longterm tretinoin treatment do not have a higher incidence of skin cancers. Tretinoin has in fact proved to be effective in the treatment of photoaging and actinic keratoses. 

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