Herpes zoster isolated in the glossopharyngeal nerve: a case report and literature review

Varicella zoster virus (VZV) can cause chickenpox (varicella zoster) and shingles (herpes zoster). Herpes zoster can affect cranial nerves but rarely impacts the glossopharyngeal nerve (GN) in isolation. We present a literature review examining primary research-published between 2012 and 2022-reporting herpes zoster affecting the GN, while also reporting a case of a 57-year-old male who presented to his primary health physician with a unilateral (right-sided) vesicular eruption of the soft palate with severe odynophagia and a generalised headache. Eight articles were included in the review, where patients' ages ranged from 27-78 years and were equally male and female (four cases each). In all cases within the review, the herpes zoster manifested as a polyneuropathy impacting the GN among alongside other cranial nerves. In our case, the VZV was confirmed by polymerase chain reaction (PCR) assay obtained from the vesicular lesions. The patient was treated with oral Famiclovir 250 mg and analgesia for 5 days. One week later, the patient returned with excruciating pharyngitis. Physical examination showed an absent right-sided gag reflex, hypogeusia on the right posterior tongue, muffled hearing on the right side, and sharp pain over the right ear, scalp, and orbit. Magnetic resonance imaging (MRI) showed thickening and linear enhancement of the right GN, consistent with neuronitis. Here, we report a literature review of herpes zoster affecting the GN and a unique case of herpes zoster isolated to the right GN. Herpes zoster of the GN most often occurs in the context of a polyneuropathy, which we demonstrate in our review.