The effects of skin pigment and thickness on skin photosensitivity

Objective To investigate the effects of skin pigment and thickness and the association of skin photosensitivity.Methods 31 subjects were exposed to two different Ultraviolet rays,before what Mexameter MX 16,Chromameter CR400 and skin B-ultrasonic were used to assess the text sites,then minimal erythema dose(MED)and minimal persistent pigment darkening dose(MPPD)were obtained.Results MPPD was negatively correlated with b*,MI,Depth,though MED was positively correlated with the three,and all of the correlation coefficients were statistically significant.Different skin photoreaction with the same UVA energy was affected by b*,Depth,and different skin photoreaction with the same UVB energy was affected by MI,EI,b*,Depth,and the correlation coefficients were statistically significant.Conclusion Skin UV sensitivity can be influenced by skin color,melanin and skin thickness.The tanning and erythematous degree after UV irradiation can be influenced by skin color,melanin,haemoglobin and skin thickness.