Diffuse hyperkeratosis in a deaf and blind 48-year-old woman-diagnosis.

An 83-year-old man with a history of diabetes and chronic obstructive pulmonary disorder (COPD) (taking prednisone, 5 mg/d) was admitted to our facility with a monthlong history of persistent right arm swelling, erythema, and pain. He had multiple prior admissions for this issue and was treated with oral and intravenous antibiotics for a suspected “cellulitis.” His skin symptoms worsened despite treatment, and he developed an extensive superimposed pustular eruption with sinus tracts involving the entire forearm and a portion of the upper arm (Figure 1). Workup included ultrasonography, which showed no fluid collection, and magnetic resonance imaging, which showed soft-tissue swelling without evidence of any underlying myositis or osteomyelitis. A Tzanck smear failed to show multinucleated giant cells. Punch biopsy specimens for culture and histopathologic analysis were obtained (Figure 2 and Figure 3). What is your diagnosis?