A Clinical Trial of Topical Bleaching Treatment with Nanoscale Tretinoin Particles and Hydroquinone for Hyperpigmented Skin Lesions

BACKGROUND: Although combined use of tretinoin (all-trans-retinoic acid; atRA) and hydroquinone improves various hyperpigmented lesions, the pharmacologic instability of atRA and atRA-induced irritant dermatitis are difficult unsolved problems. OBJECTIVE: The objective was to evaluate the efficacy and adverse effects of a newly formulated gel containing inorganic-coated atRA nanoscale particles (nano-atRA gel). METHODS: Nano-atRA gel was used in our two-phased bleaching protocol: 5% hydroquinone and 7% lactic acid ointment were used along with nano-atRA gel in the bleaching phase (2-8 weeks), and 5% hydroquinone and 7% ascorbic acid ointment were used alone during the healing phase (4-8 weeks). Eighty-four patients with facial hyperpigmented lesions were enrolled in this study, and 77 of them (88 lesions) followed up for more than 10 weeks were analyzed. RESULTS: Hyperpigmentation was improved in 84 of 88 lesions (95.5%) after a mean treatment period of 14.3 weeks and was almost eliminated in 52 lesions (59.1%). Nano-atRA gel caused exfoliation and scaling similar to that seen with conventional atRA gel, whereas the erythema seen in the bleaching phase appeared to be weaker. CONCLUSION: Nano-atRA gel can improve hyperpigmentation to a similar extent as conventional atRA gel. It also induces irritant dermatitis, but with less erythema.