Effectiveness, safety, and effect on quality of life of topical salicylic acid peels for treatment of postinflammatory hyperpigmentation in dark skin.

Background: There are no randomized split-face model studies investigating treatments for postinflammatory hyperpigmentation (PIH) in dark skin.
Objective: To assess the efficacy, safety, and effect on quality of life of salicylic acid peels for PIH in dark skin.
Methods: Ten subjects with Fitzpatrick skin phototypes IV to VI were randomized to receive two 20% salicylic acid peels followed by three 30% salicylic acid peels to half of the face. The contralateral half remained untreated. Response was evaluated by photography reviewed by three blinded dermatologists. The Visual Analog Scale, Dermatology Life Quality Index (DLQI), and treatment quality questionnaire were administered.
Results: Improvement of PIH on the treatment side according to each rater (p=.81, p=.81, p=.42) and according to the raters combined (p=.11) approached but did not reach statistical significance. Subjects' Visual Analog Scale scores indicated significantly greater improvement of PIH on the treatment side than in the control (p=.004). Quality of life measured according to the DLQI improved after treatment but not statistically significantly so (p=.13). Treatment had no significant adverse effects.
Conclusions: Salicylic acid peels are safe in this population. Although patients rated them as clinically effective, blinded raters found a brief series of peels to have less efficacy. Measured quality of life improved nominally.