The combination of 2% 4‐hydroxyanisole (mequinol) and 0.01% tretinoin effectively improves the appearance of solar lentigines in ethnic groups

While the efficacy and safety of topical 4-hydroxyanisole (mequinol) 2%/tretinoin 0.01% therapy has been established in Caucasian populations, those with skin types I-II, little research has focused on individuals with darker skin types. The purpose of this open-label study was to evaluate the efficacy and safety of mequinol 2%/tretinoin 0.01% solution in the treatment of solar lentigines in Asian, Latin/Hispanic, and African American ethnic groups with skin types II-V. Subjects were required to have >or= 10 solar lentigines on the dorsal forearms/hands and >or= 3 on the face. One lesion was designated the target lesion, however, all lesions were treated. Patients were treated with topical mequinol 2%/tretinoin 0.01% and clinically evaluated at 4, 8, 12, 16, 20, and 24 weeks as well as 4 weeks following treatment cessation. At each visit, lesions were evaluated using Target and Overall Lesion Pigmentation Index scores ranging from 0 (lightest) to 8 (darkest), where 4 indicated equal pigment with surrounding skin. Efficacy was determined based on pigmentation index scores, and safety was assessed using laboratory monitoring and adverse event (AE) reporting. Over 80% of the 259 subjects completing this study responded to mequinol 2%/tretinoin 0.01% therapy, with a majority of subjects maintaining clinical benefit at 4 weeks post-treatment. Most AEs reported were tolerable and overall mequinol 2%/tretinoin 0.01% therapy had a favorable benefit-to-risk ratio. This study therefore supports the theory that topical mequinol 2%/tretinoin 0.01% is an effective and safe treatment of solar lentigines in ethnic populations, and in those with dark skin types.