Soru

During routine morning rounds in the newborn nursery, a physician evaluates a male neonate at $48$ hours of life due to a newly developed cutaneous eruption. The infant was born at $39$ weeks gestation via an uncomplicated spontaneous vaginal delivery to a $26$-year-old primigravida. The mother's prenatal laboratory screening was unremarkable. The infant has been breastfeeding robustly and passing normal transitional stools. Vital signs demonstrate a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), a heart rate of $138/\text{min}$, and a respiratory rate of $38/\text{min}$. Physical examination highlights a well-appearing, alert neonate. A widely disseminated rash consisting of prominent erythematous macules and papules is visible across the anterior thorax, back, and proximal thighs. Several of the erythematous bases contain small, $1\text{- to }2\text{-mm}$ central yellowish pustules. The palms and plantar surfaces are completely clear of lesions. A Wright-stained smear of the pustular contents is examined under light microscopy and demonstrates a striking predominance of eosinophils. Based on these findings, which of the following is the most appropriate next step in management?