Re-examining mechanic's hands as a characteristic skin finding in dermatomyositis

Mechanic's hands is a poorly defined clinical finding that has been reported in a variety of rheumatologic diseases. Morphologic descriptions include hyperkeratosis on the sides of the digits that sometimes extends to the distal tips, diffuse palmar scale, and (more recently observed) linear discrete scaly papules in a similar lateral distribution. The association of mechanic's hands with dermatomyositis, although recognized, is still debatable. In this review, most studies have shown that mechanic's hands is commonly associated with dermatomyositis and displays histopathologic findings of interface dermatitis, colloid bodies, and interstitial mucin, which are consistent with a cutaneous connective tissue disease. A more specific definition of this entity would help to determine its usefulness in classifying and clinically identifying patients with dermatomyositis, with implications related to subsequent screening for associated comorbidities in this setting.