[en] Administration, Topical ; Adult ; Ascorbic Acid/analogs & derivatives/therapeutic use ; Densitometry/methods ; Dermatologic Agents/therapeutic use ; Dicarboxylic Acids/therapeutic use ; Double Bind Interaction ; Drug Combinations ; Female ; Forearm ; Glucosamine/analogs & derivatives/therapeutic use ; Hand ; Humans ; Image Processing, Computer-Assisted ; Lentigo/drug therapy/etiology/metabolism ; Melanins/metabolism ; Melanocytes/drug effects ; Middle Aged ; Pilot Projects ; Plant Extracts/chemistry/therapeutic use ; Pyrones/therapeutic use ; Soybeans/chemistry ; Sunlight/adverse effects
[en] BACKGROUND: So-called darkened age spots encompass distinct pathological processes. The efficacy of topical depigmenting agents is difficult to objectivate. OBJECTIVE: To assess the hypopigmenting effect of three cosmetic formulations using objective biometrological methods. METHODS: 50 women of South-East Asian ancestry were enrolled in this pilot study. They had solar lentigines according to dermoscopic criteria. The lesions were treated by topical hypopigmenting formulations. Products were applied twice daily for 2 or 3 months. Assessments at 1-month intervals were made using narrow-band reflectance spectrophotometry, image analysis of video-recorded ultraviolet light reflection and photodensitometry- and image-analysis-assisted corneomelametry. RESULTS: A 20% azelaic acid formulation and another one containing 5% ascorbyl glucosamine, 1% kojic acid and alpha-hydroxyacid esters appeared inefficacious on solar lentigines. A stabilized soy extract showed a better although modest lightening effect when assessed by corneomelametry. The subclinical or faint mottled skin revealed by ultraviolet light examination better responded (p < 0.05) to treatments. CONCLUSION: Focal epidermal hyperpigmentation is better controlled by topical whitening agents when the increase in melanin content reflects a modest functional hyperactivity of melanocytes.