Skin involvement is present in all SSc patients and has a centripetal course, affecting hands and face early and electively, with the potential involvement of all the other skin areas. In SSc, skin involvement evolves through oedematous, sclerotic and atrophic phases. Hand disability develops since oedematous phase, in which oedema reduces fingers movement and hands functionality. Oedema is prominently related to the microangiopathy of the lymphatic vessels, contemporary to the microangiopathy of the blood microvessels, causing leakage of fluid and macromolecules in the interstitial tissues (6). In the following sclerotic phase, the skin becomes fibrotic, increases its consistency and becomes inelastic, impossible to be lifted in folds, shiny, tight and adherent to the subcutaneous tissue. In the later atrophic stage, the skin is thinned, due to the reduction in thickness of the dermis. In the hands, the progressive skin sclerosis leads, firstly, to flexion deformity of the fingers and, then, to the typical disabling claw hands, characterised by ankylosis in flexion of the proximal and distal interphalangeal (IP) joints, loss of flexion of the metacarpophalangeal (MCP) joints, loss of mobility of the thumb, blocked in adduction and flexion. The reduction of flexion-extension of the wrist is concomitant. In the atrophic stage, hand movements are further reduced, especially with regard to pronation-supination of the radio-ulnar joint
Hand Function in Scleroderma / A. Del Rosso; S. Maddali Bongi; M. Matucci Cerinic. - STAMPA. - (2014), pp. 71-89.