Visual Diagnosis

Presentation

A 7-day-old female infant presents to the emergency department with the complaints of perceived back pain and subjective fevers. Her mother also describes unexplained skin color changes to her infant's back and shoulders. For the past 2 days, the mother had noticed that her infant was fussy and would cry when her back was touched. She has no other systemic symptoms, no sick contacts, and no known history of trauma. The mother has no reported history of methicillin-resistant Staphylococcus aureus infection or colonization. This is the first time the mother has sought medical attention for her baby since discharge from the newborn nursery.

The child was born by vacuum-assisted vaginal delivery at 39 weeks' gestation and weighed 3.8 kg. Labor had been induced because of maternal preeclampsia. Meconium-stained amniotic fluid was present on delivery. Apgar scores were 3 and 8 at 1 and 5 minutes, respectively. The infant did not require resuscitation and was admitted directly to the newborn nursery, where she stayed for 3 days. The mother had adequate prenatal care and no serologic evidence of prenatal infections. Of note, because the mother had one prior spontaneous abortion, she had received Rho (D) immune globulin during this pregnancy.

Physical examination reveals an afebrile, irritable infant. Examination of the skin demonstrates a warm, confluent, blanching, erythematous, and somewhat purpuric area covering the upper third of her back (Fig. 1). Areas of induration are scattered over the patient's upper back and posterior axillae (Fig. 2). Shotty lymphadenopathy is noted in both axillae. The rest of the physical examination findings are unremarkable.