Mechanic hands: clinical and capillaroscopy manifestations of patients with connective tissue diseases presented with and without mechanic hands.

Mechanic hands can be a presenting sign of some systemic connective tissue diseases. Probably, finding this sign on examination, especially together with Raynaud's phenomenon or abnormal capillaroscopy, can be helpful in the early diagnosis of the connective tissue diseases and can be used as a predictive and prognostic tool in future studies.