A quantitative method for the assessment of the microtopography of human skin.

The skin relief influences the exterior aspect of the skin which is very sensitive to aging. It could also be related to the mechanical properties and structure of both dermis and stratum corneum. Consequently, quantitative measurement of the skin surface roughness would seem most useful, as it would permit a quantification of skin aging, an in vivo analysis of mechanical forces acting on the skin structure, and the detection of abnormalities otherwise not visible. The method described comprises three steps: (1) making a silicone rubber negative replica, (2) making an Araldite positive cast, (3) roughness measurement of the cast with a device commonly used in engineering, which provides quantitative parameters: Ra, Rp, Rt, Rmax and others. The reliability of each of these steps was checked, and also the absolute need to locate precisely the site of sampling and to know the angle of the scanning direction with the main axis of the limb or the body. The method seems useful for studying aging, either normal or affected by UV rays and other physiopathological events influencing the skin surface.