56-year-old man with skin...

A 56-year-old man presents to the dermatology out-patient clinic with a 2-year history of an asymptomatic eruption on his limbs. Lesions initially appeared on the dorsi of his hands, but over the past two years they have also appeared on his elbows and ankles. He is otherwise well.

Examination 

He has an erythematous eruption consisting of grouped lesions on his hands, elbows and ankles. On the dorsi of his hands the lesions consist of discrete annular and polycyclic lesions with a raised erythematous edge and central clearing. On palpation the lesions are indurated (firm thickening of the dermis) with no surface change such as xerosis or scaling (normal epidermis).