Approach to a rash in the well newborn and infant: Clinical sciences

A three-day-old newborn girl is being evaluated for a rash. She was born at 40-weeks of gestation via uncomplicated vaginal delivery. Her mother says the rash first began two days after birth as multiple small red flat and raised lesions on the trunk. The rash appeared spontaneously and was not associated with exposure to temperature changes. Weight is in the 85th percentile, length is in the 85th percentile, and head circumference is in the 90th percentile. The patient is sleeping but is arousable and moves all four extremities equally. Rectal temperature is 37°C (98.7°F), heart rate is 183/min, and blood pressure is 73/50 mmHg. Physical examination shows numerous macules on erythematous bases with central pustules on the trunk as seen in the image below. No rash is seen over mucosal, palmar, or plantar surfaces. Cytologic examination of pustular fluid from one of the lesions reveals a predominance of eosinophils. Which of the following is the most likely diagnosis?


[URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4372928/. Image taken from script]