Two of the most commonly used chemical peels for acne treatment produced similar results in a small clinical study, but one led to more durable improvement and caused fewer side effects than the other.
Both salicylic acid and glycolic acid produced similar statistically significant (P<0.05) improvement after two treatments, Dee Anna Glaser, M.D., of St. Louis University, and colleagues reported in the February issue of Dermatologic Surgery.
But at two months of follow-up, there was more sustained improvement with the salicylic acid peel. Also, patients reported more adverse effects after the first treatment with glycolic acid.
“We expected to see a significant difference in effectiveness between the two peels owing to their different lipophilic properties, but out study did not prove this supposition,” the authors said. “Efficacy of chemical peels beyond a few weeks post-treatment is not well documented in the literature, but our study found that patients demonstrated significant sustained clinical improvement on the salicylic acid peel-treated side [of the face] at two months post-treatment.”
Inducing partial-thickness skin injury, superficial chemical peels are frequent adjuncts to treatment of facial acne vulgaris. Glycolic acid, a hydrophilic a-hydroxy acid, causes desquamation that reduces corneocyte cohesion and keratinocyte plugging, enabling extrusion of inflammatory contents. Salicylic acid, a lipophilic ß-hydroxy acid, also reduces corneocyte cohesion and works well on sebaceous areas of the face, the authors said.
To address a lack of comparative data, Dr. Glaser and colleagues studied 20 patients ages 13 to 38. The patients had mild or moderately severe facial acne, averaging 27 lesions at enrollment.
In accordance with the split-face, double-blind, randomized design, one half of each patient’s face was treated with glycolic acid and the contralateral side was treated with salicylic acid. The agents were applied every two weeks for a total of six treatments.
By the second treatment visit, both chemical peels had demonstrated similar and statistically significant decreases in acne lesions. The reduction in acne lesions continued through the first month of follow-up, averaging 43% with glycolic acid and 47% with salicylic acid (P<0.05). Blinded assessment revealed good or fair improvement on both sides of the face in 19 of 20 patients.
At the two-month follow-up, blinded evaluation demonstrated 75% improvement on the glycolic acid-treated side of the face and 81% on the side treated with salicylic acid. However, patients had developed more new acne lesions on the side of the face treated with glycolic acid. In contrast, the lesion number continued to decrease on the side of the face treated with salicylic acid (P<0.01 versus baseline).
Patient self-assessment showed that 41% of the study group thought the glycolic acid peel had led to more improvement compared with 35% of the salicylic acid side of the face. The remaining patients thought both peels worked equally well or that neither side of the face had improved (12% each). Additionally, 53% of the patients though the glycolic acid side “looked the best,” compared with 47% for salicylic acid peel.
The two types of chemical peels were associated with a similar number of adverse events, occurring most frequently during the first two treatments and then declining thereafter. The most commonly reported adverse events were peeling, redness, and scaling. Patients reported more adverse events on the glycolic acid side of the face after the first treatment but the difference was not significant from treatment with salicylic acid.
“The different lipophilic properties of the peels did not appear to impact their clinical effectiveness,” the authors concluded. “Our findings suggest that either a- or ß-hydroxy acid peel may be effectively used to treat mild or moderately severe facial acne vulgaris.”