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

Summary 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 ≥ 10 solar lentigines on the dorsal forearms/hands and ≥ 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.