Papulonecrotic eruption in a 44-year-old-man.

A patient is described who presented with the acute onset of widely distributed necrotic papules mimicking pityriasis lichenoides et varioliformis acuta. A skin biopsy revealed granulomatous inflammation and spirochetes were demonstrated. Serologic testing confirmed infection with the Treponema pallidum. Syphilis is still a great imitator and its persistence as an infectious disease is reviewed.