A 70-year-old male presents with vesicular lesions near his left ear that are spreading toward his mouth. He reports having had a childhood illness that caused a widespread rash. Which pathogen is responsible for his current condition?

Correct answer: C. Varicella-zoster virus (VZV)

• A. CMV usually causes subclinical infection in immunocompetent children and does not reactivate as unilateral vesicular facial lesions.
• B. HSV-1 causes primary herpetic gingivostomatitis and recurrent herpes labialis; it does not cause a widespread childhood rash.
• C. CORRECT. VZV causes chickenpox (varicella) in childhood. After primary infection, the virus remains latent in dorsal root and cranial nerve ganglia. Reactivation in the elderly or immunocompromised causes herpes zoster (shingles). Involvement of the geniculate ganglion (CN VII) produces Ramsay Hunt syndrome — zoster lesions in the ear with ipsilateral facial nerve palsy and taste disruption.
• D. EBV causes infectious mononucleosis, not a childhood vesicular rash, and does not reactivate as unilateral vesicular lesions.