PresentationA 20-month-old girl presents to the emergency department with a 5-day history of fever, "red eyes," and a rash. Three days ago she was given amoxicillin for an ear infection. The morning after starting amoxicillin, she developed a rash. She had been in good health and has had no exposure to other drugs, illness, or insect bites. Her past medical history and review of systems are unremarkable.On physical examination, she appears fussy and irritable. She has a temperature of 103°F (39.4°C), heart rate of 167 beats/min, and respiratory rate of 48 breaths/ min. The neck is supple, and there is bilateral conjunctival injection without discharge. Her tongue is red, as are her lips, which are fissured (Fig. 1). A 1-cm lymph node is palpable on the left side of her neck. Skin examination reveals a red, blanching, slightly raised, polymorphous rash over her extremities (Fig. 2). She has mild nonpitting edema of her hands and feet (Fig. 3). Findings on the remainder of her examination are normal.A complete blood count demonstrates: hematocrit, 30% (0.30); white blood cell count, 13.7ϫ10 3 /mcL (13.7ϫ10 9 /L) with 59% neutrophils and 33% lymphocytes; and platelet count, 563ϫ10 3 /mcL (563ϫ10 9 /L). Serum electrolytes, glucose, and creatinine concentrations and findings on urinalysis are normal. Examination of the cerebrospinal fluid reveals: white blood cell count, 84/mm 3 ; glucose, 60 mg/dL (3.3 mmol/L); protein, 84 mg/dL (840 g/L); and no organisms on Gram stain. *Lincoln Hospital, Bronx, NY.Figure 1. Red, fissured lips.Figure 2. Polymorphous red rash over extremities.Figure 3.