Viral Infections USMLE Step 1 Practice Question
A 5-year-old boy presents with 3 days of high fever (39.8°C) followed by a diffuse maculopapular rash on the trunk and face as fever subsides. Vital signs show HR 110/min, RR 24/min, BP 105/68 mmHg, and SpO2 98% on room air. The rash blanches with pressure and spares the palms and soles. He attends daycare and has no history of varicella vaccination. CBC shows lymphocytic predominance. Which of the following is the most likely diagnosis?
Answer choices
- AVaricella
- BRoseola infantum (human herpesvirus 6)Correct answer
- CScarlet fever
- DRubella
- EMeasles
- FErythema infectiosum (fifth disease)
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