title: In vivo study of skin mechanical properties in Raynaud's phenomenon.
abstract: OBJECTIVE
  Raynaud's phenomenon (RP) is usually the first symptom in patients with systemic sclerosis (SS) and may precede skin changes by several months or years. Non-invasive measurements of skin elasticity are very sensitive and appropriate for objective and quantitative evaluation of sclerodermatous skin. The aim of this study was to investigate and compare the mechanical properties of the skin in patients with primary, secondary, and suspected secondary RP.
  
  
  METHODS
  A total of 63 patients were studied. They were classified as having scleroderma-type nailfold capillary abnormalities--17 with indurative phase of scleroderma (group 1), nine with edematous phase of scleroderma (group 2), 18 with suspected secondary RP (group 3) and as having RP-type nailfold capillary abnormalities, 19 with primary RP (group 4). Thirty-nine sex- and age-matched healthy individuals with normal nailfold capillaroscopy pattern were also studied as controls. Mechanical properties of the skin were evaluated using a non-invasive suction device (Cutometer) equipped with a 2 mm probe. Measurements were performed over five anatomic regions: cheeks, volar forearms, wrists, hands, and proximal phalanx of the fingers. The skin mechanical parameters analyzed were distensibility (Uf), elasticity (Ua/Uf) and viscoelasticity (Uv/Ue).
  
  
  RESULTS
  Most demonstrative changes were observed over volar forearms. Patients included in groups 1-3 were characterized by significantly lower Uf and higher Uv/Ue compared with patient group 4 and controls. Patient groups 1 and 2 showed significantly lower Ua/Uf, as well. There were no significant differences in skin mechanical parameters between patient group 4 and control group.
  
  
  CONCLUSIONS
  Mechanical properties of the skin in patients with suspected secondary RP significantly differ from these in patients with primary RP and resemble those in patients with edematous phase of scleroderma. Our findings suggest that the non-invasive measurements of skin elasticity could be helpful in identifying patients with RP at risk of developing SS.
authors.affiliation: Department of Dermatology and Venereology, Medical University, Plovdiv, Bulgaria. hristo_dobrev@hotmail.com
authors.forename: Hristo
authors.initials: H
authors.lastname: Dobrev
mesh_terms: D001696:Biomechanical Phenomena / Q000379:methods; D004548:Elasticity; D005260:Female; D006244:Hardness; D006245:Hardness Tests; D006801:Humans; D008297:Male; D011928:Raynaud Disease / Q000150:complications / Q000503:physiopathology*; D012595:Scleroderma, Systemic / Q000150:complications / Q000503:physiopathology*; D012867:Skin / Q000503:physiopathology*; D013314:Stress, Mechanical; D014783:Viscosity