Image analysis of scaly skin using Dsquame(R) samplers: technical and physiological validation

An image analysis-based technique for evaluating skin scaliness using Dsquame(R) instant testers is presented, with four surface texture parameters characterizing this condition. Studies on the variability of the technique were carried out to determine the influence of instrumental and physiological factors. Parameters of texture, optical density, number and surface area of squames are calculated from images of obliquely lit Dsquame(R) samples. Repeated measurements were done on artificial and real samples to determine instrumental and sample variability, respectively. In addition, the technique was used in a volunteer study to assess anatomical differences and seasonal variation. For five consecutive measurement days, the artificial samples remained stable, with coefficients of variation for repeatability and reproducibility of less than 8% for all parameters. During the same period, the real samples showed decreases mainly in those parameters of texture and optical density. In the volunteer study, the calf showed significantly higher values (more scaly) in December than July, with no seasonal change in forearm or crow's foot area sites. Assessments of Dsquame(R) instant tester samples using image analysis-derived parameters provides information on the quantity and quality of skin scaliness or flakiness. As such, it is a useful tool for studying desquamation. The technique presented is repeatable and reproducible; however, samples need to be analysed the same day to avoid deterioration problems. Anatomical differences have been demonstrated, with, in addition, the calf showing marked winter/summer changes in comparison to the face and forearm.