How to Manage Acute Herpes Zoster Affecting Trigeminal Nerves

Correction

The original article listed an incorrect dosage amount in the ‘Treatment’ section. It now reads: Valacyclovir 1000 mg or 1 G (orally, 3 times daily for 7 days).

Acute herpes zoster affecting trigeminal nerves

Orofacial acute herpes zoster (shingles) is an acute viral disease affecting the trigeminal nerve (CN V). It is the result of reactivation of the varicella zoster virus (VZV) that remained dormant in the trigeminal nerve root ganglion following exposure or clinical manifestation of chickenpox. Reactivation could be due to immunosuppression, or it could be age-related.

Presentation

Population

• Individuals aged 60–70 years (6–7 cases per 1000 person-years) and older than 80 years (>10 cases per 1000 person-years).
• Younger patients with immunosuppression
• Acute herpes zoster affects more than 1 million people in the US each year.
• Incidence of zoster infection is reported to be 3–4 cases per 1000 person-years.
• Acute herpes zoster affects trigeminal nerves in about 10—15% of all zoster cases.

Signs

• Ophthalmic division (V1) of the trigeminal nerve is most commonly affected.
• Vesicles appear along the path of dermatome (Fig. 1).
  • Macules and papules progress into vesicles and pustules that eventually dry, leaving a crusting appearance after 5–7 days.
• Vesicles in the cornea may lead to ulceration.
• Ramsay Hunt syndrome, which induces facial palsy, loss of taste, buccal ulceration and appearance of rash in the auditory canal on the affected side; intraoral mucosal ulceration may also be part of the spectrum with or without full manifestation of Ramsay Hunt syndrome.

Symptoms

• Itching, tingling or pain sensation in the rash.
• Burning and tingling sensation (paresthesia/dysesthesia) in the affected side of face, including oral cavity.
• Sharp, shooting pain in response to light touches (allodynia).
• Prolonged or exaggerated response to painful sensation (hyperalgesia/hyperesthesia).
• Odontogenic pain owing to maxillary (V2) and mandibular (V3) nerve division.

Investigation

1. Obtain a detailed patient history, including history of chickenpox or acute herpes zoster. If patient reports history of VZV, note:
   • Location of lesions.
   • Lesions involving dermatomes.
   • Symptoms associated with lesions.
   • Trigger points that aggravate pain.
   • Lesions limited to the midline.
   • Swelling on the affected side.
2. Inquire about type of pain experienced (i.e. paresthesia, dysesthesia, allodynia and hyperalgesia).
3. Look for swelling on the affected side.
4. Order laboratory tests, such as direct immunofluorescence assay for VZV antigen or a polymerase chain reaction (PCR) for VZV DNA for atypical rash.

Diagnosis

Based on the patient's medical history and on clinical findings, such as blisters, swelling and laboratory results, a diagnosis of acute herpes zoster can be established.

Unilateral rashes (not crossing midline) and blisters are key signs for ruling out the diagnosis of herpes zoster virus affecting the trigeminal nerve.

Differential Diagnosis

• Herpes simplex virus
• Erysipelas
• Bullous pemphigoid
• Pemphigus vulgaris
• Bell palsy
• Trigeminal neuralgia
• Postherpetic neuralgia

Treatment

Common Initial Treatments

1. Refer the patient to a primary care physician for antiviral therapy:
   • Acyclovir 800 mg (orally, 5 times daily for 7–10 days)
   • Famciclovir 500 mg (orally, 3 times daily for 7 days)
   • Valacyclovir 1000 mg or 1 G (orally, 3 times daily for 7 days).
   • Brivudin 125 mg (orally, once daily for 7 days; not approved for use in Canada)
2. Pain management is one of the most important factors in the management of acute herpes zoster infection.Always consider prescribing anticonvulsants for management of neuropathic pain conditions, as patients do not respond well to strong analgesics, such as opioids.
   • Gabapentin 600–900 mg (orally, 1 time daily for 10 days) or 300 mg (orally, 2 or 3 times daily for 10 days)
   • Pregabalin 75 mg (orally, 2 times daily for 10 days).
   • Nortriptyline 25 mg (orally, 1 time daily at bedtime, increasing the dosage by 25 mg every 2–3 days as tolerated).
   • Amitriptyline 25 mg (orally, 1 time daily at bedtime, increasing the dosage by 25mg every 2–3 days as tolerated)
   • Oxycodone 5 mg (orally, 4 times daily for 10 days)
   • Tramadol 50 mg (orally, 2 times daily for 10 days)

Alternate Treatments

• Corticosteroids have been shown to be effective in reducing duration of pain in elderly patients.

Some practitioners, depending on the patient's response, have also suggested topical anesthetics for pain relief:

• Benzocaine cream (apply to the affected area 2–4 times daily)
• Lidocaine cream (apply to the affected area 2–4 times daily)
• EMLA® cream (apply to the affected area 2–4 times daily)

Complications

• The most common complication of acute herpes zoster is the progression of disease into a prolonged phase known as postherpetic neuralgia. At times, patients present with postherpetic neuralgia, which becomes a diagnostic challenge as the neuropathy persists after resolution of the skin or mucosal lesions.
  • Other less common complications include encephalitis, herpes zoster–related opthalmicus with delayed contralateral hemiparesis, myelitis and VZV-related retinitis.

Advice to practitioner

Recommend the herpes zoster vaccine (Zostavax®) to patients. The Centers for Disease Control and Prevention (CDC) states that patients aged 60 years and older should be vaccinated regardless of prior exposure to VZV.  However, the vaccine is approved for patients as young as 50 years. The vaccine reportedly reduces the incidence of herpes zoster by 48%, but it is less effective in immunosuppressed patients.

Precautions for Shingles Vaccine

• If a patient presents with signs and symptoms of shingles, wait for the viral infection to resolve then consider for vaccine to prevent reoccurrence of herpes zoster infection.
• Zostavax® should not be administered in children or in patients with known: allergic reaction, immunosuppression, ongoing cancer therapy or pregnancy.
• After the vaccine has been administered, the patients might experience redness and rash-like appearance near the site of injection.

THE AUTHORS

	Dr. Klasser is associate professor, Louisiana State University School of Dentistry, department of diagnostic sciences, New Orleans, LA, USA.
	Dr. Ahmed is a PhD candidate, faculty of dentistry, McGill University, Oral Health and Society Research Division, Montreal, Canada.

Correspondence to: Dr. Gary D. Klasser, Louisiana State University School of Dentistry, department of diagnostic sciences, 1100 Florida Ave., Box 140, New Orleans, LA 70119, USA. Email: gklass@lsuhsc.edu.

The authors have no declared financial interests.

This article has been peer reviewed.