Shingles (Herpes Zoster)

General Information

Classification: Integumentary

What is it?

Source: OpenI (NLM)

Extremely painful, self-limiting vesicular rash due to the reactivation of varicella zoster virus in dorsal root ganglion nerves; is also known as herpes zoster

Lesions follow dermatomes due to nerve involvement (most commonly affecting thoracic and cervical dermatomes)

Presents with acute neuritis


Risk Factors: older age, immunosuppression, transplant patients, female (increased susceptibility to autoimmune issues), malignancy

Other manifestations

Herpes Zoster Opthalmicus: shingles infection of the eye (and potentially skin of neighboring areas) that can progress into blindness

Herpes Zoster Oticus: infection of potentially all parts of ear (Ramsay Hunt Syndrome Type II: if comes with facial paralysis)

Evaluation:

  • Primarily clinical: fever, malaise, burning pain, typical distribution and characteristics of lesions
  • Tzanck smear of vesicular fluid
  • Direct fluorescent antibody testing
  • PCR for viral DNA
  • Serology to assess immunity (igM or igG against VZV)


Pathophysiology:

  • Virus replicates in neural cell bodies, and synthesized virions are then carried to the skin innervated by the respective ganglions, causing inflammation and blistering and extreme pain
  • Specific involvement of Gasserian/trigeminal nerve ganglion

Phases of infection:

  1. Pre-eruptive (pre-herpetic neuralgia): nerve pain prior to vesicle eruption in affected dermatomes
    • Accompanied by headache, malaise, myalgia, fatigue
    • Over the course of a few days
  2. Acute eruptive: lesion transformation from macules to painful herpetiform vesicles (will ulcerate and crust over) on an erythematous base
    • Lesions do not cross midline since are localized to a dermatome, so an abrupt/sudden stop in lesions should be found
    • 2-4 weeks
  3. Chronic phase: post-herpetic neuralgia (no eruption)
    • Persistent, recurring pain and/or paresthesias that lasts longer than 4 weeks
    • Higher rates in elderly
    • Can extend from months to years

Treatment & Prevention

Source: OpenI (NLM)

If <72 hours: antiviral therapies (valacyclovir or acyclovir)

If <72 hours: treatment is not very effective, but can employ topical antibiotics (mupirocin), opioids or nerve blocks for pain, or other medications to treat complications

Preventative measures:

  • Zoster vaccine if already had VZV/chickenpox: Shingrix

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