This is the most commonly observed "rash" in the newborn, occuring to some extent in half of all neonates.
Lesions generally start on day 1 or 2 and increase in number over the next several days, followed by spontaneous resolution in about a week. The typical appearance is a central yellow plaque with a halo of erythema. It is not itchy and, whilst it can unsettle parents when florid, even newborns who have hundreds of spots are not symptomatic and need no futher evaluation.