B02.89 Other complications of zoster (including vasculopathy)
G53 Cranial nerve disorders in zoster
Pathophysiology
Primary infection and latency
Varicella-zoster virus (VZV) is a member of the herpesvirus family
Primary infection (chickenpox) occurs via respiratory droplets or contact with vesicular fluid
VZV travels via sensory nerve axons to dorsal root ganglia or cranial nerve ganglia
Establishes lifelong latency in sensory neurons
Reactivation mechanism
Decline in VZV-specific T-cell immunity triggers reactivation
VZV travels anterograde along sensory nerve to skin
Produces the characteristic dermatomal vesicular eruption
Ganglionic necrosis and haemorrhage produce the acute neuritis
Postherpetic neuralgia mechanism
Viral damage to peripheral and central pain pathways
Loss of large myelinated inhibitory afferents
Central sensitization and altered pain processing
Allodynia and hyperalgesia from damaged nociceptors
Complications pathophysiology
HZO: direct corneal invasion via nasociliary branch; immune-mediated inflammation
Ramsay Hunt: involvement of geniculate ganglion affecting CN VII and VIII
VZV vasculopathy: direct viral invasion of cerebral vessel walls causing inflammation and occlusion
Disseminated zoster: haematogenous spread when T-cell immunity severely impaired
Therapeutic Considerations
Antiviral selection rationale
Valacyclovir and famciclovir preferred over acyclovir
Valacyclovir is an L-valyl ester prodrug of acyclovir with 3–5 times higher oral bioavailability
Simpler dosing improves adherence: TID vs 5 times daily for acyclovir
Clinical trial data: median pain duration 38 days vs 51 days for acyclovir (P=0.001)
IV acyclovir remains standard for severe or CNS disease
PHN prevention strategy
Early antiviral therapy is the most evidence-based intervention to reduce PHN risk
Corticosteroids do not reduce PHN incidence despite improving acute pain
Amitriptyline initiated during acute episode may reduce pain at 6 months
Vaccination evidence
Shingrix (recombinant zoster vaccine with AS01B adjuvant)
97.2% efficacy in preventing herpes zoster in adults 50–69 years
91.3% efficacy in adults 70 years and older
91.2% efficacy in preventing PHN in those who develop herpes zoster
Two-dose series 2–6 months apart; both doses required for full protection
AAAAI 2026 guidelines recommend Shingrix for all immunocompetent adults 50 years and older
Immunocompromised host considerations
IV acyclovir initiation in any immunocompromised patient with evidence of dissemination
Extend antiviral duration to 10–14 days; continue until all lesions crusted
Foscarnet for acyclovir-resistant VZV (usually TK-deficient mutants from prolonged exposure)
JAK inhibitors and anifrolumab: hold if possible during acute episode
Infection control
Localized zoster: not airborne; standard and contact precautions
Disseminated zoster: airborne and contact precautions (may behave like varicella)
Susceptible healthcare workers should not care for disseminated zoster patients
Patient Discharge Instructions
copy discharge instructions
Diagnosis and cause
Herpes zoster (shingles) is caused by reactivation of the chickenpox virus in nerve roots
Once you have had chickenpox, the virus can remain dormant in your nerves for years
Stress, illness, or a weakened immune system can trigger reactivation
Your medication instructions
Take your antiviral medication (valacyclovir or famciclovir) exactly as prescribed
Take all doses for the full course even if the rash starts healing
Start as soon as possible: antivirals work best when started early
For pain: take acetaminophen or ibuprofen as directed
Stronger pain medications prescribed: take only as needed
Gabapentin or pregabalin: do not stop suddenly; side effects include drowsiness
Drink plenty of fluids while taking antiviral medication
Wound and skin care
Keep rash clean and dry
Apply calamine lotion to reduce itching
Cover rash with clean loose clothing or light bandage to prevent spreading
Do not pop or scratch blisters
Contagion and contact precautions
You cannot give someone shingles, but you CAN spread chickenpox to someone who has never had it
Avoid direct contact with rash fluid until all blisters have crusted over
Avoid pregnant women who have not had chickenpox or the vaccine
Avoid newborn babies and immunocompromised individuals until crusted
Expected course
New blisters form for 3–5 days, then crust over by 7–10 days
Skin usually heals within 2–4 weeks
Some pain may last after the rash heals (postherpetic neuralgia); follow up if this occurs
Follow-up appointments
Primary care in 1–2 weeks to check healing and pain control
Eye doctor appointment: required if you have rash near your eye even if vision seems fine
Return to emergency department immediately for
New or worsening eye pain, redness, or blurred vision
Facial weakness or drooping
Ear pain with blisters in or around the ear
Hearing loss or severe dizziness
Rash spreading to many parts of your body
Fever with confusion, severe headache, or neck stiffness
Weakness in an arm or leg
Difficulty urinating
Vaccine to prevent recurrence
Shingrix vaccine (2 doses) recommended for adults 50 years and older
Discuss with your family doctor timing of vaccination after this episode
References
Guidelines and key sources
Cohen JI. Herpes Zoster. New England Journal of Medicine 2013
Comprehensive review covering epidemiology, treatment, and antiviral data
Primary evidence base for antiviral selection and timing
Behera D, Belemkar S. Epidemiology, Treatment, and Management of Herpes Zoster. Current Pharmaceutical Design 2026
Updated review of HZ epidemiology, risk factors, and management
Saguil A et al. Herpes Zoster and Postherpetic Neuralgia: Prevention and Management. American Family Physician 2017
PHN risk factors and pain management strategies
Gilden DH et al. Neurologic Complications of Reactivation of Varicella-Zoster Virus. NEJM 2000
VZV encephalitis, myelitis, and vasculopathy; CNS complication management
Whitley RJ. A 70-Year-Old Woman With Shingles: Review of Herpes Zoster. JAMA 2009
Clinical review with epidemiology and treatment updates
Uscategui T et al. Antiviral Therapy for Ramsay Hunt Syndrome. Cochrane Database 2008
Combined antiviral and corticosteroid therapy for Ramsay Hunt evidence
Johnson RW, Rice AS. Postherpetic Neuralgia. NEJM 2014
PHN pathophysiology, incidence, and treatment evidence
Gan EY, Tian EA, Tey HL. Management of Herpes Zoster and Post-Herpetic Neuralgia. American Journal of Clinical Dermatology 2013
PHN treatment options including topical agents
Espinoza S et al. High-Resolution MRI for Early Diagnosis of Orbital and Neurovascular Involvement in HZO. American Journal of Ophthalmology 2026
MRI protocol for HZO neuro-ophthalmic complications
Slimovitch J et al. Recommended Vaccines for Immunocompetent Older Adults. Journal of Allergy and Clinical Immunology in Practice 2026
AAAAI 2026 Shingrix vaccination recommendations
McKay SL et al. Herpes Zoster Risk in Immunocompromised Adults in the United States. Clinical Infectious Diseases 2020
Systematic review of HZ risk in immunocompromised populations
IDSA/OARAC Guidelines for Prevention and Treatment of Opportunistic Infections in Adults with HIV 2025
VZV management in HIV-positive patients; CD4-specific guidance
Adriaansen EJM et al. Herpes Zoster and Post Herpetic Neuralgia. Pain Practice 2024
Evidence-based PHN management framework
Tao BK, Soor D, Micieli JA. Herpes Zoster in Neuro-Ophthalmology. Eye 2024
HZO and neuro-ophthalmic manifestations practical guide
Jiao S. From Zoster to Polyneuropathy: Cranial Nerve Involvement in Ramsay Hunt Syndrome. Frontiers in Neurology 2025
Ramsay Hunt pathophysiology and cranial nerve manifestations
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.