Abstract
A 30-year-old female with a history of interstitial lung disease presented with non-pruritic scaling and fissuring of her hands and feet. She denied muscle weakness. Examination revealed hyperpigmented lichenified plaques on all digits and no heliotrope rash was present. Laboratory workup revealed positive autoantibodies for anti-KU and anti-SSA and elevated levels of aldolase and creatine kinase. ANA and anti Jo-1 antibodies were negative. These clinical and laboratory findings were highly suspicious for dermatomyositis (DM). A biopsy of a brown macule on the first toe was performed. Histopathologic evaluation of the biopsy showed hyperkeratosis, focal parakeratosis, and psoriasiform acanthosis without any significant suprapapillary thinning. Of particular note, there were numerous apoptotic keratinocytes extending into the upper spinous layer that were out of proportion with the minimal interface inflammation present. Colloidal iron showed increased dermal mucin deposition. A diagnosis of mechanics hands (MH) / hikers feet (HF) was rendered. MH / HF was first reported in 1979 as non-pruritic, hyperkeratotic plaques distributed bilaterally and symmetrically on the hands and / or feet resembling the calloused hands of a mechanic or the calloused feet of a hiker. MH / HF is most often associated with antisynthetase syndrome, a rare inflammatory muscle disease related to DM, but it has also been reported in mixed connective tissue disease and systemic lupus erythematosus. In addition, DM associated with MH often shows positive anti-Jo-1 antibodies although not always and has a high association with interstitial lung disease as in our case.
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