Pityriasis rosea is a relatively common skin disorder. In its typical form it is easily recognizable; however, atypical forms can pose diagnostic problems. We report a 44-year-old woman with an acute onset of a localized eruption on her left breast. The morphology of the rash and the time course were typical of pityriasis rosea. Localized pityriasis rosea is an unusual variant, which has been described previously.