What virus is responsible for roseola infantum?

• A. Human immunodeficiency virus
• B. Human herpesvirus 6
• C. Varicella-zoster virus
• D. Measles virus

Answer: (B)

Roseola infantum, also known as sixth disease, is primarily caused by Human herpesvirus 6 (HHV-6). This viral infection is most commonly observed in infants and young children, typically between the ages of 6 months and 2 years. The hallmark of roseola is a sudden high fever that lasts for a few days, often followed by a distinctive rash once the fever subsides. The rash typically starts on the trunk and then spreads to the limbs, characterized by small pink spots that fade with pressure.

Human herpesvirus 6 is part of the herpesvirus family and has two variants: HHV-6A and HHV-6B. While both variants can be involved in infections, HHV-6B is most frequently associated with roseola infantum. Understanding the specific viral etiology is crucial for diagnosing and managing the condition effectively, differentiating it from other viral exanthems that can present similarly but have different causative agents.