Rash in a 2-month-old Premature Infant

An 82-day-old girl presents with a 4-day history of a generalized rash without other systemic symptoms. She was born at 32 weeks’ gestation of a dichorionic triamniotic pregnancy. Her neonatal course was uncomplicated, and she was discharged along with her 2 brothers at 47 days of life. The rash began with 1- to 3-mm papules and vesicles on the anterior neck and then spread to her face and scalp over the next 24 hours, with spread of macules, papules, and pustules over the next several days to the chest, torso, and lower extremities (Fig). The infant appears well, is afebrile, is not scratching, and is not irritable. The infant’s mother denies exposure to anyone with rash. The infant does not attend child care, but her 4-year-old sibling does. Her parents and siblings report being healthy, and the 2- and 4-year-old siblings are both fully immunized for age per...