Shiny, skin-colored, pinhead-sized grouped papules on a young boy

A 4-year-old white male presents with a 3-month history of an asymptomatic papular rash on his back, abdomen, chest, upper arms, and ankles. His medical and family histories are otherwise unremarkable. On examination, the grouped papules are shiny, monomorphic, skin-colored, and pinhead-sized. The papules exhibit koebnerization but no erythema or tenderness. His nails, hair, oral mucosa, and genitals are normal. ...