Plicometer skin test: a new technique for the evaluation of cutaneous involvement in systemic sclerosis

This study tries to establish a new method for the evaluation of skin lesion extension and progression in systemic sclerosis (SSc) patients. Plica thickness measurements of 200 healthy subjects and 19 SSc patients by plicometer were performed, and an arbitrary plicometer skin score was created. The plicometer skin score was compared to m-Rodnan's score on the same patients. The statistical association between the plicometer score and DLCO values in SSc patients was analysed. Plicometer plica thickness cut-off values of normality were established for nine skin areas. High specificity (95-99%) and a high negative predictive value (95.5-100%) were found. The sensitivity and the positive predictive value were 52.6-100% and 52.4-90.5%, respectively. The coefficient of variation of the plicometer score (0.05-0.14) was lower than that of the m-Rodnan score (0.22-0.33). A statistically significant association was found between skin score and DLCO. The study underlines the accuracy and reproducibility of the plicometer skin test, and suggests its utility in monitoring scleroderma progression.