A 54-year-old woman presented with a painful pruritic rash on the hands and feet of 7 years’ duration. She reported intermittent joint pain but denied muscle weakness. Physical examination revealed fissured fingertips and heavy scaling of the palms and lateral fingers (Figure 1). Violaceous scaly papules were seen on the distal and proximal interphalangeal joints (Figure 2). A severe plantar keratoderma also was noted (Figure 3). Pink scaly plaques were present on the bilateral elbows and postauricular skin. Diffuse mat telangiectases covered the malar skin. Extensive poikilodermatous skin changes covered approximately 20% of the total body surface area. Salt-and-pepper patches and papules were noted over the bilateral thighs. She reported an uncertain history of recent radiographs of one or both hands, which showed no joint degeneration characteristic of psoriatic arthritis. She previously had been given a diagnosis of psoriasis by an outside dermatologist but was not responding to topical therapy.
Several skin biopsies showed histologic evidence of dermatomyositis (DM)(Figure 4). Prominent basement thickening also was seen on periodic acid–Schiff staining (not shown). Laboratory workup showed negative antinuclear antibodies and anti–Jo-1, anti-Ku, and anti-Mi2 antibodies. Muscle enzymes including creatinine kinase and aldolase were within reference range. Pelvic ultrasonography and mammography were negative. Pulmonary function tests were unremarkable. High-resolution chest computed tomography (CT) was ordered because of a history of chronic cough; however, no evidence of malignancy or interstitial lung disease was seen. The patient was diagnosed with amyopathic dermatomyositis (ADM). Rheumatology was consulted and initiated oral hydroxychloroquine therapy. After 3 months, the patient’s cutaneous disease did not respond and she reported having headaches associated with this medication; therefore, methotrexate was started. Within 2 months of treatment, full resolution of the plantar keratoderma (Figure 5) and clearance of the scaling/fissuring of the hands as well as the psoriatic-appearing plaques on the elbows was noted.