Topical tretinoin (retinoic acid) treatment of hyperpigmented lesions associated with photoaging in Chinese and Japanese patients: a vehicle-controlled trial.

Background: Hyperpigmented lesions are a predominant component of photoaging in Chinese and Japanese persons. Topical 0.1% tretinoin cream improves the hyperpigmentation associated with photoaging in Caucasian persons.
Objective: Our purpose was to assess the efficacy of 0.1% tretinoin cream treatment of hyperpigmented lesions associated with photoaging in Chinese and Japanese patients.
Methods: Forty-five photoaged patients (23 Chinese, 22 Japanese) completed a double-blind, randomized study in which 21 applied 0.1% tretinoin cream and 24 applied vehicle cream once daily to face and/or hands for 40 weeks. Patients' hyperpigmented lesions were evaluated clinically and by colorimetry throughout the study and by histologic analysis of skin biopsy specimens taken before therapy and at the end of treatment.
Results: At the end of treatment, hyperpigmented lesions of the face and hands were lighter or much lighter in 90% of patients receiving tretinoin compared with 33% receiving vehicle (p < 0.0001). Colorimetry demonstrated significant lightening of lesions after tretinoin compared with vehicle (p < 0.05). Histologic analysis of hyperpigmented lesions demonstrated a statistically significant 41% decrease in epidermal pigmentation with tretinoin therapy as compared with a 37% increase in the vehicle group (p = 0.0004). No patient withdrew for adverse effects.
Conclusion: By clinical, colorimetric, and histologic evaluation, 0.1% tretinoin cream significantly lightens the hyperpigmentation of photoaging in Chinese and Japanese patients.