Test your diagnostic skills in our regular dermatology quiz. What is the cause of this progressive skin discolouration on a man’s lower legs?
A 64-year-old man presents with a four-year history of progressive bilateral discolouration of the lower legs. Over the preceding four weeks, his symptoms have worsened, with increasing pruritus, pain and erythema and the development of weeping bullae and erosions. He is systemically well with no fever.