Your Diagnosis, Please
A previously healthy 7-year-old boy presented to the emergency department (ED) in winter because of pruritic exanthema on the distal areas of his upper and lower extremities and fever up to 38.5°C for 1 day.
He was born in Spain to a family of Moroccan origin and had no travel history. He had no known allergies, was fully immunized, and had no known contact with animals, new foods or detergents. His parents and siblings were healthy.
On admission to the ED, the patient had a temperature of 37.9°C, blood pressure of 125/87 mm Hg and heart rate of 157 beats/min. Physical examination was notable for a symmetric maculopapular and petechial rash primarily involving the distal extremities, including the hands and feet. There were also purpuric lesions in the oral cavity (Fig. 1). He had no lymphadenopathy or meningeal signs. The remainder of his examination, including cardiac and neurologic systems, was normal.
Laboratory testing revealed a white blood cell count of 8200/µL (51% neutrophils, 45.1% lymphocytes, 2.1% monocytes, 1.6% eosinophils, 0.1% basophils), platelet count of 81,000/µL, C-reactive protein of 1.8 mg/dL and procalcitonin of 1.16 ng/mL. Coagulation studies were mildly abnormal, including the international normalized ratio of 1.3 and prothrombin activity of 66%. The rest of his laboratory parameters (hemoglobin, hematocrit, urea, creatinine, electrolytes and glucose) were normal. Pharyngeal swab for detection of group A streptococcus, blood cultures and serologic testing (IgM and IgG) for parvovirus B19, Epstein-Barr virus and Toxoplasma gondii were all negative.
The patient was admitted to the hospital. Additional testing revealed the diagnosis.
For Denouement see P. 1255.