Epidemiology

Etiology

Pathophysiology

Clinical features

• Main symptoms: dermatomal distribution, typically affecting 1–3 dermatomes on one side of the body (most commonly affects the cervical, trigeminal, thoracic, and lumbar dermatomes)
  • Pain
    • The most frequent symptom and may precede the rash
    • Usually described as “burning”, “throbbing”, or “stabbing”
    • Allodynia may occur.
  • Erythematous maculopapular rash that quickly evolves into vesicular lesions
    • Vesicles are initially clear.
    • Pustulation and rupture typically occur after 3 or 4 days.
    • Crusting and involution typically occurs between day 7 and 10.
    • Lesions may become necrotic, generalized, or may not be present at all.
• Additional symptoms
  • Fever, headache, and fatigue

Subtypes and variants

Herpes zoster ophthalmicus (HZO)

• Definition: reactivation of VZV in the ophthalmic division of the trigeminal nerve
• Clinical features
  • Fever and skin symptoms as in shingles
  • Herpes zoster conjunctivitis
  • Herpes zoster keratitis
  • Involvement of the ophthalmic nerve: reduced corneal sensitivity with severe pain in the innervated regions (forehead, bridge and tip of the nose)
  • Involvement of the nasociliary nerve:
    • Possible severe intraocular infection (uveitis, iritis, conjunctivitis, keratitis, and optic neuritis)
    • Positive Hutchinson sign of the nose: a vesicular rash on the nasal alae

Herpes zoster oticus

• Definition: reactivation of VZV in the geniculate ganglion, affecting the seventh (facial) and eighth (vestibulocochlear) cranial nerves (also known as Ramsay Hunt syndrome)
• Clinical features
  • Fever and skin symptoms as in shingles in the auditory canal and pinna (see “Clinical features” above)
  • Vestibulocochlear nerve involvement → vertigo and sensorineural hearing loss (SNHL)
  • Facial nerve involvement → ipsilateral facial paralysis

Diagnostics

Positive Hutchinson sign of the nose: a vesicular rash on the nasal alae

Treatment

Complications

Postherpetic neuralgia

• Definition: chronic neuropathic pain persisting for at least three months in the area previously affected by the rash
  • Postherpetic neuralgia only happens in VZV, not other herpesviruses
• Epidemiology
  • Most common complication (occurs in 10–20% of overall herpes zoster cases)
  • Strong association with age
• Risk factors
  • Age > 50 years
  • Severe infection (severe pain or rash)
• Clinical features
  • Pain (including allodynia, paresthesias, dysesthesias) in the same dermatome as the rash
  • Duration of symptoms > 3 months but can persist for years
• Treatment
  • One of the following tricyclic antidepressants:
    • Reduces serotonin and norepinephrine at the same time
    • Amitriptyline
    • Nortriptyline
    • Relative contraindications: patients with heart disease, epilepsy, or glaucoma
    • Should be used with caution in elderly patients
  • One of the following anticonvulsants:
    • Pregabalin
    • Gabapentin
  • Topical treatments
    • Capsaicin patch or cream