Alpha-hydroxy acids and photodamaged skin – adapted from the Arch Dermatol 1996;132;631-6 – Tips from Other Journals
Public interest in the use of alpha-hydroxy acids to reduce the effects of photodamage on the skin has resulted in a marketing effort that approaches $300 million in prescription and nonprescription sales per year, despite lack of placebo-controlled trials. Use of alpha-hydroxy acids has been advocated for acne, seborrheic and actinic keratosis and extrinsically aged skin. A recent study has demonstrated that use of alpha-hydroxy acids at high concentrations induces the synthesis of mucopolysaccharides and collagen in photodamaged skin. Stiller and associates performed a 22-week double-blind, vehicle-controlled study to assess the safety and efficacy of these topical agents.
Sixty-seven evaluable women participated in the trial. Two widely used topical alpha-hydroxy acids, 8 percent glycolic acid and 8 percent L-lactic acid creams, were applied twice daily to the face and outer aspect of the forearms. A vehicle-only cream was applied as the control agent. All test creams were oil-in-water emulsions using the same vehicle as Pond’s Age Defying Complex. Only one study subject withdrew because of cutaneous irritation on the face from the L-lactic acid cream.
A significantly higher number of subjects who used either of the two active drug agents showed improvement of photodamage, compared with those using only the vehicle. More than 70 percent of the subjects using either of the active agents had a reduction of photodamage on the face by week 22, compared with only 41 percent of the vehicle-treated subjects. Both of the active agents reduced photodamage on the forearms. No differences were observed between the two active agents at either site.
Of the clinical signs of photodamage, hyperpigmentation was the most significantly improved on the forearm with use of either alpha-hydroxy acid after 10 weeks of treatment. However, this difference narrowed among the three treatment groups after week 14. At the end of the study, only the 8 percent L-lactic acid cream continued to show a significant advantage over the vehicle. A similar non-significant trend was noted with regard to hyperpigmentation on the face. Similar trends were noted in assessing improvement in sallowness of the forearms and face. Tactile roughness showed the greatest mean reduction from baseline after treatment with both alpha-hydroxy acids and the vehicle cream.
Subjects who used the active drugs on the face reported improvement more often on self-assessment scores. Only subjects who used either of the alpha-hydroxy agents noticed a significant improvement from baseline in numbers of fine wrinkles, age spots or evenness of color. However, overall improvement was noted with the vehicle. Of the three parameters (erythema, scaling and dryness) used to assess adverse reactions, only erythema differed significantly among the three agents. Thirty percent of subjects had some degree of erythema at one or more treatment sites at any one time.
The authors conclude that both 8 percent glycolic acid and L-lactic acid are well tolerated and have a modest beneficial effect on mild to moderately photoaged skin, compared with the control vehicle. (Stiller MJ, et al. Topical 8% glycolic acid and 8% L-lactic acid creams for the treatment of photodamaged skin. Arch Dermatol 1996;132:631-6.)
COPYRIGHT 1996 American Academy of Family Physicians
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