“Hiker’s feet”: a novel cutaneous finding in the inflammatory myopathies

Abstract

Mechanic’s hands is a well-characterized manifestation of select idiopathic inflammatory myopathy (IIM) syndromes. Less well characterized is the hyperkeratosis of the toes and plantar surface of the feet that can also accompany these disorders. We aim to describe common pedal signs in the context of IIM, and suggest that it may be another key feature in the presentation of these syndromes. A cohort of 2145 myositis patient charts gathered since 2003 were retrospectively reviewed using the key search terms “mechanic’s feet” and/or “mechanic’s foot.” Charts that included either phrase were further reviewed for clinical characteristics. Nine patients were identified with documentation describing “mechanic’s feet” or “mechanic’s foot.” All nine affected individuals carried a diagnosis of DM, seven of whom also met criteria for antisynthetase syndrome. In eight patients (89%), it presented in conjunction with mechanic’s hands. Six (67%) presented with anti-Jo-1 antibodies, and three (33%) were seronegative. Although the term “mechanic’s feet” has been used to describe this clinical finding in patients in our myositis cohort, we propose the term “hiker’s feet,” given that the presentation resembles a callousing pattern more typical of avid hikers or long-distance walkers. Prevalence data are not yet known but should be considered for further study. If the presenting signs of IIM are expanded to include hiker’s feet, it could aid in not only diagnosis and management but also provide insights into the pathophysiology of these diseases.