differential diagnosis

Infant girl develops bulging sacral massA 3-week-old female presented to the emergency department with a 3-day history of a progressively enlarging, erythematous, seemingly painful lump on her back.
Stubborn ring of rash around a boy's mouthThe mother of a healthy 11-year-old boy brings him to the office for help to clear a rash that has persisted around his mouth for 3 months. Although the boy rarely licks his lips, he does not use lip products and has not changed his dental products.
Infant’s seizures and skull fracture could point to child abuseA 5-month-old Hispanic male presented to the emergency department (ED) at a children’s hospital in the Northeast United States directly from his daycare after caretakers witnessed 2 shaking, seizure-like episodes. The episodes lasted 1 to 2 minutes in the setting of a fever as palpated by the parents.
Nervous teenager’s hands turn blueThe father of a healthy 15-year-old girl brings her to the emergency department (ED) for evaluation of blue hands.
Tight, shiny membrane encases newborn’s skinAfter a cesarean delivery at 30 weeks, a 1430-gram premature female neonate was noted to have generalized thick, dark brown scale forming a tight membrane over her entire skin surface. Her mother was a healthy 19-year-old gravida 1 with normal prenatal screening ultrasound and laboratory studies. Family history did not reveal any congenital malformations or genetic disorders.
Recurrent brown spots in an infant girlA mother brings her healthy 6-month-old girl to the outpatient clinic with disseminated, asymptomatic, golden-brown bumps that occasionally become red and swollen.
Small-for-age toddler is unable to walkA 22-month-old African American boy born at 38 weeks by normal vaginal delivery presents to a local hospital from a private pediatric office for failure to thrive. He was seen by his pediatrician until aged 1 month but was lost to follow-up. His delay in walking prompted his mother to reestablish care at age 22 months.
Newborn with persistent hypoglycemiaA full-term male infant was born to a 33-year-old gravida 3, para 3 mother. The prenatal course was uncomplicated, without gestational diabetes; the mother received prenatal care at an out-of-state institution. At the delivery, however, the baby was notably macrosomic, with shoulder dystocia and perinatal distress requiring positive pressure ventilation.
Infant with facial lesions and respiratory distressA 2-month-old Hispanic girl is transferred by her pediatrician to the emergency department (ED) for evaluation of decreased oral intake, failure to thrive, and large bleeding facial hemangiomas.
Autoimmune diseases as noninfectious causes of feverFever without infection can be a manifestation of a number of different disorders in children, including various autoimmune and autoinflammatory diseases.