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

OBJECTIVES: The condition known as 'Mechanic's Hands' is a thickened, hyperkeratotic eruption, which is bilaterally symmetric along the fingers, and often occurs in patients with some connective tissue diseases. Nail fold capillaroscopy is a non-invasive technique for evaluation of connective tissue diseases. We evaluated the prevalence of mechanic hands in patients with connective tissue diseases and compared the clinical manifestations and capillaroscopic changes in the patients with and without mechanic hands.

METHODS: The clinical manifestations and capillaroscopy of 576 patients with scleroderma, dermatomyositis, systemic lupus erythematosus, Sjogren's syndrome, undifferentiated and mixed connective tissue diseases were evaluated and compared in patients with and without mechanic hands.

RESULTS: A total of 576 patients were enrolled. Mechanic hands were observed in 17.2% of patients: 50% of mixed connective tissue disease, 35% of dermatomyositis, 15.4% of scleroderma, 14.9% of undifferentiated connective tissue disease, 14.3% of Sjogren's syndrome, and no patient with SLE. Among them, 80.8% had abnormal capillaroscopic findings. In dermatomyositis patients, Raynaud's phenomenon, anti-Jo-1 positivity, and some capillaroscopy findings were detected more frequently in patients with mechanic hand. In scleroderma, positive Scl70 and capillary loss were observed more frequently in patients without mechanic hands.

CONCLUSIONS: 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.