Clinical Study Of UVA,UVB And Blue Light Induced Erythema And Pigmentation On Healthy Females With Skin Phototype Ⅲ-Ⅳ In Yunnan Area

Objective:This study aims to investigate the effect of UVA,UVB and blue light induced erythema and pigmentation on healthy females with skin phototype Ⅲ-Ⅳ in Yunnan area,which would provide a theoretical basis for sun protection.Methods:Thirty-two healthy female subjects with skin phototype Ⅲ-Ⅳ were enrolled in the study.All subjects were irradiated on their inner forearm and back using three light sources:UVA,UVB and blue light of different doses.Evaluations were performed at 24 h after irradiation.The Investigator’s Global Assessment Score for erythema and pigmentation was evaluated,and a*value,L*value were measured for all sites and control site at all visits,△ a*value,and △L*value was measured for all test sites.The t test,ANOVA test and rank sum test were performed and all analyses were down by using SPSS23.0 software.Results:1.The a*value and L*value between the inner forearm and the back have no significant difference in all subjects.2.The IGA scores for pigmentation and a*value increased,L*value decreased after UVA irradiation.The IGA scores for erythema and a*value increased,L*value decreased on the UVB irradiation side.However,the IGA scores for pigmentation and erythema,a*value increased,L*value decreased after blue light irradition.And the erythema and pigmentation intensity of skin were greater with minimal dose of blue light than with UVA and UVB.Conclusions:Our study demonstrates erythema and pigmentation are observed after UVA,UVB,and blue light irradiation,while the erythema and pigmentation intensity induced by minimal dose of blue light greater than minimal dose of UVA and UVB.These findings suggest blue light may be an environmental important factor in inducing hyperpigment diseases and emphasize the importance of blue light protection when using sunscreen to against UV.