Skin extensibility and consistency in patients with Ehlers-Danlos syndrome and benign joint hypermobility syndrome

Objectives: The reproducibility of clinical tests for skin extensibility and consistency, essential for differentiating between types of Ehlers-Danlos syndrome (EDS) and benign joint hypermobility syndrome (BJHS), is unknown. Paraclinical methods may provide objective differential diagnostic methods. Methods: Six EDS, 11 BJHS, and 19 controls completed the trial. We analysed the overall inter-examiner agreement on clinical tests for skin extensibility and consistency, in addition to analyses on suction cup (SC) and soft tissue stiffness meter (STSM) methods. Results: Overall agreement on tests for skin extensibility and consistency varied between 0.44 and 0.72. Extensibility evaluated by SC showed an insignificant difference between EDS patients and controls (p=0.056). Consistency evaluated by STSM showed significant differences (p=0.001). Conclusions: Overall inter-examiner agreement on clinical tests for skin extensibility and consistency was below 0.80, which was required a priori to conduct a reproducibility study. Further refinement of tests and a training phase are necessary. The SC and STSM results are encouraging but must be reproduced in a larger study population.