Topical glycolic acid enhances photodamage by ultraviolet light.
BACKGROUND
Alpha-hydroxy acids (AHAs) are widely used as ingredients in cosmetics. Several studies suggest that AHAs can increase the sensitivity of skin to ultraviolet (UV) light.


OBJECTIVE
This study was performed in order to determine whether short-term dermal treatment with glycolic acid, a representative AHA, can enhance the damaging effects of UV light. The duration of the effect of AHAs on the sensitivity of skin to UV light was also examined.


METHODS
The backs of 29 Caucasian subjects were treated, once daily, 6 days per week with either 10% glycolic acid (pH 3.5) or placebo in a randomized double-blinded study. At the end of 4 weeks, sites within each treated area were exposed to 1.5 MED of UV light, determined on previously untreated skin. Specimens were obtained for enumeration of sunburn cells (SBCs) in the first group of subjects (n = 16), whereas cyclobutyl pyrimidine dimers (CPDs) in DNA were determined in the second group (n = 13). The minimal erythema dose (MED) in each site was also determined in the first group of subjects. Sunburn cells and MEDs were re-evaluated in the first group 1 week after discontinuing AHA applications.


RESULTS
Glycolic acid caused enhanced sensitivity to UV light measured as increased SBC induction and lowered MEDs. Cyclobutyl pyrimidine dimers were elevated but not to a statistically significant level. No differences in SBCs or MEDs were evident after a week of discontinued treatments.


CONCLUSIONS
Short-term application of 10% glycolic acid sensitizes the skin to the damaging effects of UV light. This photosensitivity is reversed within a week of terminating treatments.
Kaidbey
Kays
K
Ivy Laboratories, Philadelphia, PA 19104-3355, USA.
Sutherland
Betsy
B
Bennett
Paula
P
Wamer
Wayne G
WG
Barton
Curtis
C
Dennis
Donna
D
Kornhauser
Andrija
A
D000279:Administration, Cutaneous; D000328:Adult; D003358:Cosmetics / Q000008:administration & dosage / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006880:Hydroxy Acids / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012880:Skin Pigmentation / Q000187:drug effects* / Q000528:radiation effects*; D013471:Sunburn / Q000209:etiology* / Q000473:pathology; D014466:Ultraviolet Rays; D044465:White People
D003358:Cosmetics; D006880:Hydroxy Acids