Herpes Zoster Oticus in Emergency Medicine Overview of Herpes Zoster Oticus

Herpes zoster oticus (HZ oticus) is a viral infection of the inner, middle, and external ear. HZ oticus manifests as severe otalgia and associated cutaneous vesicular eruption, usually of the external canal and pinna. When associated with facial paralysis, the infection is called Ramsay Hunt syndrome. (See the image below.)

Ramsay Hunt syndrome accounts for up to 12% of all facial paralyses and generally causes more severe symptoms and has a worse prognosis than Bell palsy.^{[1, 2, 3]} Return-to-baseline neurologic function is predicted partially by severity of paralysis. In several studies, only 10-22% of individuals with significant facial paralysis had complete recovery. In one study, however, 66% of patients with incomplete paralysis had complete recovery.

An additional complication of herpes zoster viral infection is postherpetic neuralgia.

The incidence rates of HZ oticus in males and females are equal, and incidence increases significantly in patients older than 60 years.

Reactivation of the varicella-zoster virus (VZV) along the distribution of the sensory nerves innervating the ear, which usually includes the geniculate ganglion, is responsible for herpes zoster (HZ) oticus. Associated symptoms, such as hearing loss and vertigo, are thought to occur as a result of transmission of the virus via direct proximity of cranial nerve (CN) VIII to CN VII at the cerebellopontine angle or via vasa vasorum that travel from CN VII to other nearby cranial nerves.

Patient history

Typically, patients present with severe otalgia. Complaints include the following:

• Painful, burning blisters in and around the ear, on the face, in the mouth, and/or on the tongue (see the image below)Herpes zoster oticus. Image courtesy of Manolette Roque, MD, Ophthalmic Consultants Philippines Co, EYE REPUBLIC Ophthalmology Clinic.
• Vertigo, nausea, vomiting
• Hearing loss, hyperacusis, tinnitus
• Eye pain, lacrimation

Onset of pain may precede the rash by several hours or days. Also, in patients with Ramsay Hunt syndrome, vesicles may appear before, during, or after facial palsy (zoster sine herpete). When asked, patients may recall a distant history, perhaps in childhood, of chickenpox (varicella). A minority of patients (< 10%) give a history of previous herpes zoster viral infection.

Physical examination

Physical examination shows a vesicular exanthem, usually of the external auditory canal, concha, and pinna. The rash also may appear on postauricular skin, lateral nasal wall, soft palate, and anterolateral tongue.

Vertigo and sensorineural hearing loss may be noted, and paralysis of the facial nerve, mimicking Bell palsy, may be present. Complete loss of the ability to wrinkle the ipsilateral brow distinguishes a peripheral lesion of cranial nerve VII from a central lesion of the same nerve, which spares the forehead.

Associated findings include the following:

• Dysgeusia (alteration in taste)
• Inability to fully close the ipsilateral eye, which may lead to the occasional presentation of drying and irritation of the cornea.

Complications

Complications of HZ oticus may include the following^{[4, 5, 6]} :

• Postherpetic neuralgia
• Residual paralysis
• Rarely, herpes zoster encephalitis^[5]

Herpes zoster (HZ) oticus is caused by the reactivation of latent varicella-zoster virus (VZV) that has remained dormant within sensory ganglia (commonly the geniculate ganglion) of the facial nerve. Individuals with decreased cell-mediated immunity resulting from carcinoma, radiation therapy, chemotherapy, or HIV infection are at greater risk for reactivation of latent VZV. Physical stress and emotional stress often are cited as precipitating factors.

The differential diagnosis of herpes zoster (HZ) oticus includes the following:

• Bell Palsy
• Headache, Cluster
• Headache, Migraine
• Headache, Tension
• Herpes Zoster
• Otitis Externa
• Otitis Media
• Stroke, Hemorrhagic
• Stroke, Ischemic

Isolated facial nerve trauma also needs to be considered.

Herpes zoster oticus (HZ oticus) is primarily a clinical diagnosis in the ED.

Prior to initiating treatment with acyclovir, consider a baseline set of the following laboratory studies:

• Blood urea nitrogen (BUN)
• Creatinine
• Blood cell counts
• Electrolytes

If diagnosis of Ramsay Hunt syndrome is not established by physical examination alone, consider a head CT scan to investigate other etiologies of facial paralysis.

Until recently, therapy for herpes zoster (HZ) oticus has been generally supportive, including warm compresses, narcotic analgesics, and antibiotics for a secondary bacterial infection.

Antiviral agents

Antiviral agents clearly play a role in limiting the severity and duration of symptoms if given early in the course of the illness. Early administration (< 72 h) of acyclovir showed an increased rate of facial nerve function recovery and prevented further nerve degeneration. Furthermore, use of antivirals has been shown to decrease the incidence and severity of postherpetic neuralgia.^{[7, 8, 9, 4]}

Evidence is accumulating that varicella-zoster virus (VZV) may be responsible for many cases of Bell palsy that go unrecognized because of a lack of cutaneous findings (zoster sine herpete). Accordingly, the clinician should entertain more liberal use of antivirals such as acyclovir, valacyclovir, and famciclovir.^{[2, 3]} Studies have shown no difference between oral and IV acyclovir in immunocompetent patients with facial nerve paralysis.^[10]

Corticosteroids

Systemic corticosteroids are used to relieve acute pain, decrease vertigo, and limit the occurrence of postherpetic neuralgia. The prevailing wisdom states that treatment with acyclovir plus prednisone has more effective return to facial nerve function and prevention of nerve degeneration than treatment with prednisone alone; however, a recent review uncovered very little data to support or negate this theory.^[7] Patients treated with acyclovir plus prednisone had better outcomes (time to healing of rash, time to cessation of acute neuritis, time to return to usual activity and sleep, and time to cessation of analgesics) than those treated with either prednisone or acyclovir alone.^[11]

No evidence indicates that use of corticosteroids prevents development of postherpetic neuralgia.^{[8, 9]} Furthermore, evidence proving benefit attributed specifically to steroids is still limited, with one review showing no randomized controlled trials supporting use of steroids as an adjuvant to antiviral medications in the treatment of Ramsay Hunt syndrome.^[12]

Treatment in HIV patients

For treatment of herpes zoster in patients with HIV, inpatient parenteral regimens should be reserved for those with severe immunosuppression, trigeminal nerve involvement, ocular lesions, or multidermatomal involvement. Treatment of VZV is the same for both HIV-seronegative and seropositive patients. For acyclovir-resistant VZV, IV foscarnet is an appropriate alternative therapy (famciclovir and valacyclovir are not effective against acyclovir-resistant VZV). For outpatient regimens, famciclovir or valacyclovir for 7-10 days is recommended (both have the advantage of easier dosing regimens). Routine use of steroids is discouraged secondary to its immunosuppressive effects.^[13]

Treatment in other situations

Treatment of pregnant women with VZV is the same as that of nonpregnant women.

When secondary impetigo is present, a suitable antistaphylococcal antibiotic should be prescribed.

Cyclic antidepressants, anticonvulsants, opioids, and topical analgesics are sometimes used in the treatment of postherpetic neuralgia.^[4] These agents are more appropriately started by a pain management specialist in an outpatient setting.

Prevention of herpes zoster by vaccination is recommended for all persons older than 60 years, even if they have had chickenpox or zoster in the past. This age group suffers significant morbidity from zoster and may, therefore, benefit from the vaccine. Contraindications to vaccine administration include age younger than 60 years, current use of antivirals, pregnancy, and certain immunosuppressive conditions.^[14]

Ensure that the patient has adequate and timely outpatient follow-up for management of HZ oticus.

Emergency department care

Adequate analgesia is important for individuals with significant pain from herpes zoster. Nausea and vomiting may require ED treatment. Complications, such as corneal irritation or secondary bacterial infection of the vesicles, should be managed with routine therapies. Involvement of more than one dermatome is atypical and should prompt the search for possible immunoincompetence.

Consider admission for any of the following situations:

• Severe symptoms
• Involvement of multiple (>2) dermatomes
• Immunocompromise

Consultations

Consider an ophthalmologic consultation if corneal involvement with vesicles is noted, and consider a neurologic consultation if the etiology of the facial paralysis is unclear. Consultation with an ear, nose, and throat (ENT) specialist may be appropriate.

Prolonged or permanent facial paralysis is possible. Most patients with partial paralysis fully recover; many with severe symptoms are left with partial deficits.

Instruct patients how to tape eyes shut if lid paralysis is present.