Analytic Quantifi cation of the Bleaching Effect of a 4-Hydroxyanisole-Tretinoin Combination on Actinic Lentigines

Background: Solar lentigines represent a common feature of photoaging, particularly on the back of the hands. Bleaching agents are usually proposed to lighten the shade of the lesions.
Methods: The study was randomized and designed to assess the effect of a bleaching solution containing 2% mequinol (4-hy- droxyanisole, 4HA) and 0.01% tretinoin (Solagé®). The formulation was applied twice daily for 3 months on solar lentigines present on the back of one hand. The lesions on the other hand were treated with the ethyl alcohol vehicle which served as a control. Clinical diagnosis was confirmed using dermoscopy. In addition, objective measurements of the hypermelanosis were performed at 1-month intervals during and after treatment. Clinical assessments were used as well as narrow-band reflectance spectropho- tometry, image analysis of video-recorded ultraviolet light-enhanced visualization (ULEV method) and photodensitometry of the corneomelametry test.
Results: The multipronged assessment of the lesional color demonstrated a significant lightening effect of the 4HA/tretinoin solu- tion. This was demonstrated after 2 months of treatment and was maintained at least 2 months after stopping treatment.
Conclusion: Both the visual ratings and the objective bioinstrumental methods indicate the rapid lightening effect of the 4HA/ tretinoin formulation. After stopping treatment, the rate of repigmentation appeared to have slowed compared to the depigmenta- tion phase.