A 2-year-old boy develops high-grade fever for 3 days followed by the appearance of a maculopapular rash on the trunk and neck as the fever subsides. Which virus is the most likely cause of this illness?

• A Rubella virus
• B Parvovirus B19
• C Measles virus
• D Human herpesvirus 6 (HHV-6) ✓

Explanation

The classic presentation of high fever for 3 to 4 days followed by rash appearance as fever subsides is roseola infantum (exanthem subitum), caused by HHV-6 (and sometimes HHV-7). This is the most common exanthem in children under 2 years. Parvovirus B19 causes slapped-cheek rash (erythema infectiosum). Measella rash appears with high fever and coryza, Koplik spots precede it. Rubella rash appears with fever and posterior auricular lymphadenopathy, not after fever defervescence.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.