Chemical peels with glycolic acid, trichloroacetic acid, Jessner’s solution, kojic acid, salicylic acid, and tretinoin are used in the treatment of melasma. Peels are usually done as adjunctive therapy or when faster results are desired. Glycolic acid peels in concentrations ranging from 10% to 70% can produce excellent results in dark skinned patients, as well as in Asians and Latinos. In one study involving 25 non-pregnant women with melasma who were treated with 50% glycolic acid once a month for three consecutive months, a 91% improvement was seen (32).
Serial glycolic acid peels have been shown to provide additional benefit when added to triple-combination therapy (5% hydroquinone, 0.05% tretinoin, and 1% hydrocortisone acetate) in epidermal melasma. In a study done in 40 dark skinned Indian patients, 20 were given triple combination therapy plus serial glycolic acid peels and 20 received triple therapy alone. Both groups showed statistically significant improvement from baseline. However, there was a trend toward more rapid and greater improvement in the group receiving serial peels (33,34). Further success has been achieved through the combination of glycolic acid peels and hydroquinone with kojic acid (20).
In dark skinned patients, 1% tretinoin peels have shown similar efficacy and tolerance to 70% glycolic acid peels. In a study of Asian women, clinical, and histological improvement was achieved with twice-weekly topical 1% tretinoin peels for two-and-a – half weeks. Minimal skin reactions were noted (35).
The combination of glycolic acid peels with hydroquinone has proven no more effective than hydroquinone alone. However, the combination subjectively improves melasma. In one study, 10 Asian women were treated with a 10% glycolic acid and 2% hydroquinone combination product applied to the entire face twice daily. The patients also received a 20-70% glycolic acid peel every three weeks to one side of the face (eight peels total). All participants were evaluated by an independent dermatologist. Munsell color chart and photographs showed improvement in pigmentation and fine wrinkling on both sides of face. The side receiving glycolic acid peel showed slightly better improvement, but it did not reach statistical significance (25).
Another study of combination therapy involving hydroquinone and glycolic acid peels produced no difference in 21 Latin women with epidermal and mixed melasma. In this split-faced study lasting eight weeks, patients applied 4% hydroquinone to the entire face twice daily and 20%-30% glycolic acid peels hemifacially every two weeks (four peels total). Objective evaluation showed that both treatments significantly reduced skin pigmentation, although no significant difference between the combination therapy and hydroquinone alone were seen (37).
Superficial peels have been shown to hasten the effect of topical treatments. Sixteen women with Fitzpatrick skin types II-VI received pre-treatment peels with 0.05% tretinoin for one to two weeks. They were then given three peels one month apart in which half the face was treated with 70% glycolic acid and half with Jessner’s solution. Post-treatment was done with 4% hydroquinone and 0.05% tretinoin. Objective evaluation showed average lightening on both sides of the face (38). Similar improvement was seen in a similar study where topical tretinoin alone was used for 10 months (24).
Topical therapies can also enhance the results of resurfacing techniques. Hevia showed that 0.1% tretinoin accelerates healing after 35% trichloroacetic acid peels in a split-face, placebo-controlled study of 16 male patients. In this cohort, 75% of tretinoin- pretreated hemifaces were completely healed at day 7, as compared with 31% of the placebo-treated hemifaces (39).
Alpha-hydroxy acid peels have been shown to increase efficacy when combined with topical treatments containing bleaching agents on patients with melasma. They have also shown efficacy in patients with pigmentation due to photodamage. Alpha-hydroxy acid peels have proven safe and effective on all skin phototypes (40).