Derm Dx: A persistent pruritic rash on the buttocks

A 22-year-old man presents for evaluation of a papular eruption on his buttocks. The condition began several weeks earlier and is somewhat pruritic. Three weeks previously at another clinic, he was diagnosed with scabies and was treated with a course of oral ivermectin. Examination reveals multiple flesh-colored to slightly erythematous papules of the affected area. A biopsy is obtained.