Herpes zoster oticus is an uncommon manifestation of herpes zoster that affects the 8th cranial nerve ganglia and the geniculate ganglion of the 7th (facial) cranial nerve.
Herpes zoster (shingles) is reactivation of varicella-zoster virus infection. Risk factors for reactivation include immunodeficiency secondary to cancer, chemotherapy, radiation therapy, and HIV infection. Typically, the virus remains latent in a dorsal root ganglion, and reactivation manifests as painful skin lesions in a dermatomal distribution. However, the virus rarely remains latent in the geniculate ganglion; when reactivated, the virus causes symptoms involving the 7th and 8th cranial nerves.
Symptoms and Signs of Herpes Zoster Oticus
Symptoms of herpes zoster oticus include
Severe ear pain with vesicles in the ear
Transient or permanent facial paralysis (resembling Bell palsy)
Vertigo lasting days to weeks
Hearing loss (which may be permanent or which may resolve partially or completely)
Vesicles occur on the pinna and in the external auditory canal along the distribution of the sensory branch of the facial nerve. Symptoms of meningoencephalitis (eg, headache, confusion, stiff neck) are uncommon. Sometimes other cranial nerves are involved.
Diagnosis of Herpes Zoster Oticus
Clinical evaluation
Diagnosis of herpes zoster oticus is usually clinical. If there is any question about viral etiology, vesicular scrapings may be collected for direct immunofluorescence or for viral cultures, and MRI is done to exclude other diagnoses.
Treatment of Herpes Zoster Oticus
Antivirals and corticosteroids
Sometimes for complete facial paralysis, surgical decompression of the fallopian canal
Although there is no reliable evidence that corticosteroids, antivirals, or surgical decompression make a difference in herpes zoster oticus, they are the only possibly useful treatments. When used, corticosteroids are started with prednisone 60 mg orally once a day for 4 to 7 days, followed by gradual tapering of the dose over the next 2 weeks. Either acyclovir 800 mg orally 5 times a day or valacyclovir 1 g orally 2 times a day for 10 days may shorten the clinical course and is routinely prescribed for immunocompromised patients.
Vertigo is effectively suppressed with diazepam 2 to 5 mg orally every 4 to 6 hours. Pain may require oral opioids. Postherpetic neuralgia may be treated with medications (eg, amitriptyline, nortriptyline, gabapentin, pregabalin).
The role of surgical treatment of facial paralysis remains controversial; however, surgical decompression of the fallopian canal may be considered if the facial palsy is complete (no visible facial movement). Decompression must be done within 2 weeks of onset of the facial paralysis to be effective. Before surgery, electroneurography is done. Patients with a > 90% decrement in facial movement are usually candidates for decompression.