Novel Ideas: The Increased Skin Viscoelasticity - A Possible New Fifth Sign for the Very Early Diagnosis of Systemic Sclerosis.

INTRODUCTION: Diagnosis of systemic sclerosis (SSc) at very early stage could allow starting an appropriate therapy and improving the patient outcome. Skin involvement is often the first non-Raynaud's phenomenon (RP) symptom. Its uncovering may play an important role for the initial diagnosis.

OBJECTIVE: To introduce a simplified method for non-invasive evaluation of skin mechanical properties in patients with clinically evident or suspected SSc.

MATERIAL AND METHODS: A total of 94 patients and 162 healthy subjects were studied. According to clinical and nailfold videocapillaroscopy findings the patients were divided into four groups: 20 with edematous phase of SSc (group 1), 28 with indurative phase of SSc (group 2), 26 with suspected secondary RP (group 3), and 20 with primary RP (group 4). Mechanical properties of the volar forearm skin were evaluated using a non-invasive suction device (Cutometer) equipped with 2-mm diameter probe. The skin mechanical parameters analyzed were distensibility (Uf), elasticity (Ua/Uf) and viscoelasticity (Uv/Ue).

RESULTS: Skin distensibility was reduced and skin viscoelasticity increased in group 1-3 compared to age matched healthy controls. There were no significant changes in skin elasticity. Mechanical parameters in group 4 were normal. Comparison of individual patient's values with population 95% confidence intervals of the mean showed increased skin viscoelasticity in group 1 (100%), group 2 (93%), and group 3 (81%), whereas the incidence in group 4 was 10%.

CONCLUSIONS: Noninvasive method applied is appropriate for objective and quantitative evaluation of sclerodermatous skin. In combination with nailfold videocapillaroscopy it could be predictive in pre-scleroderma patients. The increased skin viscoelasticity parameter could be proposed as the possible new fifth sign for the very early diagnosis of SSc.