Itchy violaceous papules

Over a six-week period, a 43-year-old man developed widespread itchy papules. These initially appeared over the flexor aspect of his wrists – the individual lesions were elevated and had white keratin plugs (Figure 1). Similar lesions were present over the trunk. Examination of his mucous membranes revealed a patchy, white, lace-like appearance. On skin biopsy, one of the papules showed marked lymphocytic infiltration of the upper dermis associated with damaged basal keratinocytes and vacuolar degeneration at the epidermal junction (Figure 2).