A newborn male infant was transferred to the neonatal intensive care unit for widespread vesicles and erosions evident at birth, following a spontaneous vaginal delivery complicated by fetal meconium exposure. The mother, initially unavailable for examination because she remained at the facility where she had given birth, reported via telephone that she was healthy except for a urinary tract infection for which she had taken a 7-day course of nitrofurantoin monohydrate approximately 3 to 4 weeks before delivery. She denied a history of herpesvirus infection, blistering disorder, or autoimmune disease. On physical examination, the neonate exhibited extensive erosions rimmed by purulent vesicles involving the groin, neck, scalp, fingers, and left side of the upper chest ( Figure, A and B). Mucous membranes were spared. Biopsy specimens were obtained, with results as shown in the Figure,