Roseola (exanthem subitum) is caused by which herpesvirus?

• A. HSV-1
• B. HHV-6
• C. CMV
• D. HHV-8

Answer: (B)

Roseola infantum is caused by a herpesvirus, specifically human herpesvirus 6 (HHV-6). This beta-herpesvirus typically infects young children, and the illness classically starts with a sudden high fever for several days, followed by the emergence of a diffuse rash as the fever resolves. This timing and presentation help distinguish it from other pediatric infections caused by different viruses.

Other herpesviruses listed do not cause roseola: HSV-1 leads to oral lesions and gingivostomatitis, CMV (HHV-5) can cause a mononucleosis-like illness or congenital CMV, and HHV-8 is linked to Kaposi sarcoma, especially in immunocompromised individuals. HHV-7 can also be involved in similar febrile illnesses in children, but HHV-6 remains the classic cause of roseola.