What condition is characterized by unilateral facial palsy due to reactivation of the varicella zoster virus?

The condition characterized by unilateral facial palsy due to the reactivation of the varicella zoster virus is Ramsay-Hunt syndrome. This syndrome occurs when the varicella zoster virus, which is responsible for chickenpox and shingles, reactivates in the facial nerve territory. The reactivation can lead to not only facial paralysis but also the presence of a painful rash in the ear or the mouth, which can be indicative of the viral reactivation affecting the geniculate ganglion of the facial nerve.

Ramsay-Hunt syndrome is distinct from other forms of facial nerve dysfunction because it specifically involves a viral component. In this syndrome, patients often present with symptoms like vesicular lesions on the auricle or in the oral cavity, along with hearing loss or tinnitus, making the combination of facial paralysis and these concurrent symptoms key for diagnosis.

Other options, while they may share the symptom of facial weakness, do not involve the varicella zoster virus. Bell's palsy, for instance, is an idiopathic condition that results in sudden facial paralysis, but its etiology is not related to a viral reactivation. Guillain-Barré syndrome is an autoimmune response often triggered by infections and can lead to facial weakness but is