A cosmetic preparation for the prevention of pigmentation after laser treatment of solar lentigines

BACKGROUND: Post-inflammatory hyperpigmentation (PIH) after solar lentigo removal using a Q-switched (QS) 532-nm Nd:YAG laser is a cause for concern.This study aimed to evaluate the efficacy and safety of a new depigmenting cosmetic for the prevention of PIH after QS 532-nm Nd:YAG laser treatment of solar lentigines. METHODS: In total, 20 patients with solar lentigines on the face underwent QS 532-nm Nd:YAG laser treatment. Then, the cosmetic treatment was applied from the day 5 after the treatment for 3 weeks, in 10 patients and only sunscreen was applied in the other 10 patients; treatments were randomly assigned.Two blinded dermatologists evaluated photographs at baseline, and at week 4. RESULTS:The tolerability of the cosmetic treatment was excellent or good in all patients; the tolerability of the sunscreen was excellent or good in 80% of patients and moderate in 20%. PIH was observed only in one (10%) patient after the cosmetic treatment, but it was present in six (60%) of those receiving the sunscreen (P=0.022 vs. cosmetic treatment).The relative risk of developing PIH in patients treated with the cosmetic treatment versus sunscreen was 0.17 (95% CI: 0.02-1.14, P=0.068). CONCLUSIONS: The use of this cosmetic treatment after 532-nm QS Nd:YAG laser treatment of solar lentigines can reduce the risk of developing PIH after 4 weeks.