[Objective evaluation of sclerodermic skin using the slip-test. Results and validation with 30 patients and 60...

The slip test is a non-invasive way to objectively evaluate the extent of scleroderma by measuring the "slipping" of the skin over an underlying bone. The results obtained in 30 scleroderma patients and 60 controls (178 tests due to multiple measurements) were analyzed to determine which test sites show a significant difference between patients and controls (Student's t-test) and which sites are the most discriminating for the diagnosis of the disease (multivariate analysis). Patient values were clearly distinct from those of controls. The best sites (defined by p < 0.05) were: the mandible, the second and first phalanges of the middle finger, the hands, the forearms, the epicondyles, the sternum, the iliac crests, the patellae, the tibias (the upper and lower fourths) and the feet; in all, 23 sites to which can be added the opening of the mouth (measurement of the maximal interlabial distance), which proved to be a reliable parameter. Multiple regression analysis yielded an equation that identified patients with scleroderma based on 4 variables (right forearm, right iliac crest, sternum and right rib). The slip test is thus the first reproducible quantitative test able to confirm and quantify clinical impressions in scleroderma. It is entirely able to objectively monitor the evolution of the disease under treatment. Nevertheless, complementary studies are needed to verify whether the slip test, which can be performed in 20 minutes during an office visit, can be used advantageously in the routine clinical evaluation of scleroderma.