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

Abstract

Background: 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. Methods & Findings: 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. Conclusions: 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.

Patients with Interstitial Lung Disease Secondary to Autoimmune Diseases: How to Recognize Them?

“…In this case, the hyperkeratosis is associated with cracking and dryness and involves the plantar surface, including the toes, reminiscent of the feet of long-distance walkers. The term "hiker's feet" was chosen to identify this cutaneous sign, observed in DM and ASS and associated in 90% of cases with MH [51].…”

Idiopathic inflammatory myopathies: state of the art on clinical practice guidelines

“…IIMs are generally characterised by the occurrence of muscle weakness and inflammation, but in ASSD, arthritis and interstitial lung disease (ILD) are more frequently observed and frequently represent the first manifestation of the disease 5. Skin can also be frequently affected by IIMs, with occurrence of lesions such as heliotrope rash, Gottron’s sign/papules, skin ulcers, V-sign, Shawl sign, Hiker’s feet and mechanic’s hands, with these two latter considered as typical ASSD findings 6 7. Additionally, IIMs are associated with cancer,8 the risk of which is increased up to 5.3-fold with respect to general population in males with dermatomyositis (DM) 9.…”

Patients with pure dermatomyositis/polymyositis and anti-PM/Scl autoantibody resembling anti-synthetase syndrome

“…5,7,11,13,[17][18][19] Cox et al 31 showed that, out of 9 patients with plantar hyperkeratosis, 8 had "mechanic hands" and 7 anti-synthetase syndrome. Therefore, it is possible that this plantar manifestation has the same underlying basis as "mechanic hand".…”

“…A number of studies investigating several systemic autoimmune diseases or overlap syndromes have shown that the presence of the anti-PM/Scl autoantibody is associated with pulmonary conditions, 11,15,[17][18][19]25,[28][29][30] joint conditions, 5,11,15,18,30 Raynaud's phenomenon, 11,15,18,30,31 "mechanic hands" 17,18,25,[28][29][30] and/or plantar hyperkeratosis. 5,7,11,13,[17][18][19] In this respect, the phenotypic manifestation of this autoantibody resembles that of antisynthetase syndrome.…”