Skin surface topography grading is a valid measure of skin photoaging

The technique of grading the surface topography of sun-exposed skin using silicone impressions of the skin surface is a simple, non-invasive method for measuring skin damage because of sun exposure, but it has never been validated in a community setting. To investigate the repeatability and validity of using standardly-graded skin impressions as a means of assessing skin photoaging. A random sample of 195 adults aged 18-79 years and living in Nambour, Australia (latitude, 26 degrees South) had a silicone impression taken of the back of the left hand and a 2 mm punch biopsy of the skin at the same site. Silicone impressions were graded twice independently and histological photoaging was determined by two pathologists. Grading of silicone impressions of skin surface topography was highly repeatable (weighted kappa > 0.8). Compared with those with low skin impression grades (least degeneration), people with high grades were three times more likely to show a high degree of dermal elastosis on skin histology (odds ratio 3.1, 95% confidence interval 1.6, 5.7) after adjusting for age, sex, skin colour, tanning ability, occupational exposure, smoking and height-adjusted weight. Other photoaging changes in the stratum corneum and dermis were also strongly correlated with high grades of damage on skin impressions. Grading silicone impressions of skin surface topography is a highly reliable and a valid measure of photoaging and enables prediction of dermal elastosis in a population setting.