Overview
Herpes Zoster (Shingles)
Topic Overview
Summary
Herpes zoster (shingles) is reactivation of latent varicella zoster virus (VZV) from dorsal root ganglia, causing a painful vesicular rash in a dermatomal distribution. Risk increases with age and immunocompromise. Complications include postherpetic neuralgia (PHN), ophthalmic zoster (risk of blindness), and Ramsay Hunt syndrome (facial palsy, ear vesicles). Treatment is antivirals within 72 hours of rash onset. Vaccination prevents shingles and PHN.
Key Facts
- Cause: Reactivation of latent VZV from dorsal root ganglia
- Presentation: Prodromal pain → dermatomal vesicular rash
- Complications: Postherpetic neuralgia, ophthalmic zoster, Ramsay Hunt
- Treatment: Antivirals (aciclovir, valaciclovir) within 72 hours
- Prevention: Shingrix vaccine (over 50s, immunocompromised)
Clinical Pearls
Hutchinson's sign (vesicles on nose tip) = nasociliary nerve = HIGH risk of eye involvement
Start antivirals within 72 hours of rash — reduces PHN risk
Zoster can occur without rash ("zoster sine herpete") — pain in dermatomal distribution
Why This Matters Clinically
Herpes zoster is common and can cause significant morbidity, especially PHN and blindness from ophthalmic zoster. Early antiviral treatment and urgent ophthalmology referral for eye involvement are essential.
Visual Summary
Visual assets to be added:
- Dermatomal distribution diagram
- Vesicular rash on erythematous base
- Hutchinson's sign image
- Herpes zoster management algorithm
Epidemiology
Incidence
- 2-4 per 1,000/year overall
- 10 per 1,000/year in over 80s
- Lifetime risk: 30%
Demographics
- Increases with age (over 50)
- Immunocompromised patients
- Prior chickenpox (varicella)
Risk Factors
| Factor | Notes |
|---|---|
| Age over 50 | Major risk factor |
| Immunocompromise | HIV, chemotherapy, transplant, steroids |
| Stress | May trigger reactivation |
| Recent illness |
Pathophysiology
Mechanism
- Primary varicella infection (chickenpox)
- VZV establishes latency in dorsal root ganglia
- Reactivation (waning immunity, stress, immunocompromise)
- Virus travels along sensory nerve to skin
- Dermatomal pain → vesicular eruption
Distribution
- Usually single dermatome
- Most common: Thoracic (50%), trigeminal (15%), lumbar, cervical
- Does not cross midline (unilateral)
Disseminated Zoster
- Over 20 lesions outside primary dermatome
- Immunocompromised patients
- May cause visceral involvement
Clinical Presentation
Prodrome (2-4 Days Before Rash)
Rash
Special Presentations
| Type | Features |
|---|---|
| Ophthalmic zoster (HZO) | V1 distribution; eye involvement; Hutchinson's sign |
| Ramsay Hunt syndrome | Facial nerve; ear vesicles; facial palsy; hearing loss |
| Motor zoster | Muscle weakness in affected myotome |
| Disseminated | Over 20 lesions beyond dermatome |
| Zoster sine herpete | Pain without rash |
Red Flags
| Finding | Significance |
|---|---|
| Hutchinson's sign | High risk of ocular involvement |
| Any V1 involvement | Urgent ophthalmology referral |
| Immunocompromise | Risk of dissemination |
| Disseminated rash | IV antivirals; isolation |
Pain, burning, tingling in dermatome
Common presentation.
Allodynia
Common presentation.
Systemic symptoms (fever, malaise)
Common presentation.
Clinical Examination
Skin
- Vesicles on erythematous base
- Dermatomal distribution
- Unilateral, does not cross midline
- Check for Hutchinson's sign
Eye (Ophthalmic Zoster)
- Visual acuity
- Conjunctival injection
- Corneal lesions (dendritic ulcer)
- Uveitis signs
Neurological
- Sensory changes in dermatome
- Motor weakness (rare)
- Facial palsy (Ramsay Hunt)
Investigations
Clinical Diagnosis
- Usually clinical — typical rash and distribution
Laboratory (If Uncertain)
| Test | Purpose |
|---|---|
| Viral PCR (vesicle swab) | Confirms VZV |
| Direct fluorescent antibody | Rapid diagnosis |
| Tzanck smear | Shows multinucleated giant cells (non-specific) |
Ophthalmic Zoster
- Slit lamp examination by ophthalmology
Immunocompromised
- Consider HIV testing
- Check immunoglobulin levels if recurrent
Classification & Staging
By Location
| Site | Notes |
|---|---|
| Thoracic | Most common (50%) |
| Trigeminal (V1) | Ophthalmic — risk of blindness |
| Trigeminal (V2/V3) | Maxillary/mandibular |
| Cervical | Arm/neck |
| Lumbar | Leg |
| Sacral (S2-S4) | May cause urinary retention |
By Severity
- Localised (single dermatome)
- Disseminated (immunocompromised)
Management
Antivirals — Within 72 Hours of Rash
| Agent | Dose | Notes |
|---|---|---|
| Valaciclovir | 1g PO TDS for 7 days | First-line; better bioavailability |
| Aciclovir | 800mg PO 5x/day for 7 days | Alternative |
| Famciclovir | 500mg PO TDS for 7 days | Alternative |
IV Aciclovir (10mg/kg TDS):
- Ophthalmic zoster
- Immunocompromised
- Disseminated zoster
- Ramsay Hunt
- CNS involvement
Analgesia
- Paracetamol, NSAIDs
- Neuropathic agents (amitriptyline, gabapentin, pregabalin) if needed
- Opioids for severe pain
Ophthalmic Zoster — URGENT Ophthalmology Referral
- All V1 involvement
- Especially if Hutchinson's sign
- Topical antivirals, steroids under ophthalmology guidance
Ramsay Hunt
- IV aciclovir
- Consider steroids (controversial)
- Facial physiotherapy
- Ophthalmology if facial palsy (eye protection)
Infection Control
- Infectious until lesions crusted
- Avoid contact with immunocompromised, pregnant women, neonates
- No need for isolation in immunocompetent with localised disease
Complications
Postherpetic Neuralgia (PHN)
- Pain persisting over 90 days after rash
- More common in elderly
- Difficult to treat; neuropathic agents
Ophthalmic Complications
- Keratitis, corneal ulceration
- Uveitis
- Acute retinal necrosis
- Vision loss
Other
- Secondary bacterial infection
- Motor neuropathy
- Ramsay Hunt (facial palsy, hearing loss)
- Meningoencephalitis
- Stroke (zoster vasculopathy)
Prognosis & Outcomes
Prognosis
- Most immunocompetent patients recover fully
- Crusting within 2-3 weeks
PHN Risk
| Age | PHN Risk |
|---|---|
| Under 50 | Under 5% |
| 60-69 | 10-15% |
| Over 80 | 30% |
Ophthalmic Zoster
- Risk of permanent vision loss if untreated
Evidence & Guidelines
Key Guidelines
- BASHH Guideline on Management of Herpes Zoster
- PHE Green Book (Vaccination)
Key Evidence
- Antivirals reduce duration and PHN risk if started within 72h
- Shingrix vaccine is highly effective (over 90% efficacy)
Patient & Family Information
What is Shingles?
Shingles is a painful rash caused by the same virus that causes chickenpox. The virus stays in your body and can reactivate later in life.
Symptoms
- Pain, tingling, or burning in one area
- A rash with blisters that appears a few days later
- The rash is usually on one side of the body
Treatment
- Antiviral tablets work best if started within 3 days of the rash
- Painkillers
Is it Contagious?
- You cannot catch shingles from someone else
- But the fluid in the blisters can cause chickenpox in someone who hasn't had it
Prevention
- The shingles vaccine is recommended for adults over 50
Resources
References
Primary Guidelines
- Werner RN, et al. European consensus-based (S2k) Guideline on the Management of Herpes Zoster. J Eur Acad Dermatol Venereol. 2017;31(1):20-29. PMID: 27709655
Key Reviews
- Dworkin RH, et al. Recommendations for the management of herpes zoster. Clin Infect Dis. 2007;44(Suppl 1):S1-26. PMID: 17143845
- Cohen JI. Herpes zoster. N Engl J Med. 2013;369(3):255-263. PMID: 23863052