Clinicopathological analysis of mechanic's hand associated with dermatomyositis.

Mechanic's hand is often seen in the fingers of patients with dermatomyositis and is frequently associated with anti-aminoacyl-transfer RNA synthetase autoantibodies and interstitial lung disease. We analysed the clinical symptoms of 50 patients with dermatomyositis who had visited our department, 26 of whom also had mechanic's hand. A histological examination was carried out in 16 of the 26 cases, which revealed hyperkeratosis in all cases and colloid bodies in the epidermis in 15 cases. The number of cases of interstitial lung disease in patients with mechanic's hand (22/26, 85%) was significantly higher than that in those without mechanic's hand (12/24, 50%) (P < 0.05). Mechanic's hand is an important skin lesion of dermatomyositis, and increases the likelihood of interstitial lung disease.