Purple papules in an arcuate pattern on the genitalia

An African-American man, aged 35 years, presents with a 3-month history of pruritic penile lesions. Examination reveals an arcuate pattern of raised violaceous-to-flesh-colored papules with central clearing on the glans penis and a few scattered, raised violaceous-to-flesh-colored polygonal papules of the glans penis and distal penile shaft. Results of the remainder of the skin examination are normal, and there is ...