Excellent content gathered. Here is the comprehensive OPD management guide for Varicella-Zoster:
OPD Management of Varicella Zoster (VZV) Infections
VZV causes two distinct clinical entities: primary varicella (chickenpox) and herpes zoster (shingles) from viral reactivation in sensory ganglia. OPD management differs between the two.
Part A: PRIMARY VARICELLA (Chickenpox)
Clinical Diagnosis
- Prodrome: fever, malaise 1-2 days before rash
- Rash: Generalised, centripetal, pruritic - macules → papules → vesicles ("dewdrop on rose petal") → pustules → crusts, all stages simultaneously present (pathognomonic)
- Oral/mucosal involvement common
- Highly contagious (airborne + contact) from 2 days before rash until all lesions crusted
Investigations (usually clinical diagnosis)
- If confirmation needed: PCR from vesicle fluid - gold standard (highly sensitive and specific, can distinguish wildtype from vaccine strain)
- Tzanck smear (less specific - also positive in HSV)
- Direct fluorescent antibody - rapid but less sensitive than PCR
- Serology (ELISA) - for checking immune status / post-exposure prophylaxis need
Treatment Decision by Patient Group
1. Healthy Children (2-12 years) - OPD
- Antiviral not routinely recommended - varicella is benign and self-limited; acyclovir only modestly reduces symptoms by ~1 day
- Symptomatic treatment only:
- Antipyretics: Paracetamol/acetaminophen for fever
- AVOID ASPIRIN/SALICYLATES - risk of Reye syndrome
- Pruritus relief: Calamine lotion, cool compresses, tepid baths with baking soda or colloidal oatmeal (3 cups/tub)
- Oral antihistamines (e.g., chlorpheniramine, hydroxyzine) for itching
- Keep nails short; discourage scratching (prevents secondary bacterial infection)
- Do NOT use topical steroids or occlusive ointments
2. Adolescents, Adults, Pregnant (3rd trimester), Household contacts - OPD Antivirals Indicated
These groups have more severe disease - antivirals are recommended:
| Drug | Dose | Duration |
|---|
| Valacyclovir (preferred - higher bioavailability) | 1 g orally TDS | 7 days |
| Famciclovir (preferred) | 500 mg orally TDS | 7 days |
| Acyclovir (alternative) | 800 mg orally 5 times/day | 7 days |
| Children 2-18 yrs (valacyclovir) | 20 mg/kg TDS (max 1 g/dose, max 3 g/day) | 5 days |
Key point: Start within 24 hours of rash onset for maximum benefit. Treatment beyond 24 hours is not effective for routine healthy children. - Fitzpatrick's Dermatology
Valacyclovir and famciclovir are preferred over oral acyclovir for adults because of superior pharmacokinetics and higher drug levels. - Goldman-Cecil Medicine
3. Groups Requiring IV Acyclovir (ADMIT, not OPD)
- Immunocompromised patients (IV acyclovir 10 mg/kg every 8 hours, 7-10 days)
- Varicella pneumonitis
- Varicella encephalitis
- Neonates (mothers developed varicella within 5 days before/2 days after delivery): IV acyclovir 10 mg/kg or 500 mg/m² every 8 hours for 10 days
Secondary Bacterial Infection
- Most common complication - Staph. aureus and Group A Streptococcus
- Minor infections: warm soaks
- Cellulitis: systemic antibiotics - amoxicillin-clavulanate, cefalexin, or flucloxacillin
Isolation / Infection Control (OPD Counselling)
- Keep patient away from school/work until all lesions are crusted (usually 5-7 days after rash onset)
- Avoid contact with: pregnant women, newborns, immunocompromised individuals, non-immune healthcare workers
Part B: HERPES ZOSTER (Shingles) - Reactivation
Clinical Diagnosis
- Prodrome: Dermatomal pain, burning, allodynia 2-3 days before rash
- Rash: Unilateral, dermatomal, does not cross midline - clusters of vesicles on erythematous base
- Most common: thoracic (50-70%), trigeminal (ophthalmic branch most common)
- Diagnosis is clinical in typical cases
Special Forms (flag at OPD)
| Variant | Features | Action |
|---|
| Zoster ophthalmicus (V1 - ophthalmic branch) | Rash on forehead/nose tip (Hutchinson's sign), risk of keratitis, uveitis, blindness | Urgent ophthalmology referral + IV/oral antivirals |
| Ramsay Hunt syndrome (Geniculate ganglion) | Ear vesicles + facial palsy (CN VII) + vertigo, hearing loss | Oral antivirals + prednisolone; ENT referral |
| Disseminated zoster (>3 dermatomes) | Immunocompromised | ADMIT, IV acyclovir |
| Zoster meningitis / encephalitis | Headache, confusion, neck stiffness | ADMIT, IV acyclovir |
Who to Treat with Antivirals in OPD?
| Patient group | Antiviral? |
|---|
| Age <50 yrs, mild pain, uncomplicated | Often not needed |
| Age ≥50 yrs | Yes - reduces pain duration |
| Moderate-severe pain (any age) | Yes |
| Ophthalmic/facial zoster | Yes (urgently) |
| Immunocompromised | Yes (IV if severe) |
| Still forming new lesions beyond 72 hrs | Yes, still beneficial |
Key principle: Start within 72 hours of rash onset for best effect. However, treatment may still benefit if new lesions continue to appear after 72 hours. - Goldman-Cecil Medicine
Antiviral Dosing for Herpes Zoster
| Drug | Dose | Duration | Notes |
|---|
| Valacyclovir (preferred) | 1 g orally TDS | 7 days | Higher bioavailability than acyclovir |
| Famciclovir (preferred) | 500 mg orally TDS | 7 days | Equivalent efficacy to valacyclovir |
| Acyclovir (alternative) | 800 mg orally 5 times/day | 7 days | Less preferred due to lower bioavailability |
| IV Acyclovir (severe/immunocompromised) | 10 mg/kg every 8 hrs | 7-10 days or until all crusted | ADMIT |
Topical antivirals have NO role in treatment of varicella or herpes zoster. - Fitzpatrick's Dermatology
Pain Management in Zoster (OPD)
Acute phase:
| Step | Drug | Notes |
|---|
| Step 1 | Paracetamol, NSAIDs | Mild pain |
| Step 2 | Tramadol, weak opioids | Moderate pain |
| Step 3 | Opioid analgesics (morphine, oxycodone) | Severe pain - use cautiously |
| Adjunct | Prednisolone 60 mg/day × 21 days (tapered) + acyclovir | Age >50 yrs; reduces acute pain and improves quality of life but does NOT prevent PHN |
A
2024 meta-analysis (Ding et al., PMID 39029866) confirmed that delayed initial treatment (≥3 days) is a significant risk factor for developing postherpetic neuralgia (PHN).
Early treatment is the single most important preventive step for PHN.
Wound/Skin Care
- Keep lesions clean and dry
- Saline soaks or wet compresses for comfort
- Non-adherent dressings if needed
- Prevent scratching - secondary bacterial superinfection
Part C: POST-HERPETIC NEURALGIA (PHN) - OPD Management
PHN = persistent pain >3 months after acute zoster episode. More common in elderly and in those with severe acute pain.
Evidence-Based Pharmacotherapy (RCT-proven):
| Drug | Starting Dose | Target Dose | Notes |
|---|
| Gabapentin (first-line) | 300 mg at bedtime | Up to 1200 mg TDS | Titrate slowly; causes dizziness/sedation |
| Pregabalin (first-line) | 75 mg at bedtime | Up to 300 mg BD | Faster titration than gabapentin |
| Nortriptyline / Amitriptyline (TCA) | 25 mg at bedtime | Up to 150 mg/day | Caution in elderly (anticholinergic, cardiac) |
| 5% Lidocaine patch | Apply to affected area | Up to 12 hrs/day | Useful for localised allodynia |
| Capsaicin 8% patch (high concentration) | Applied by specialist | Single application | Pain from application itself; not tolerated by ~1/3 patients |
| Tramadol / Opioids | As needed | Lowest effective dose | Last resort; long-term safety concerns |
These agents provide adequate pain relief (pain <3/10 or ≥50% reduction) in 30-60% of patients. - Fitzpatrick's Dermatology
Part D: CRITERIA FOR ADMISSION (Do NOT manage OPD)
| Situation | Reason |
|---|
| Varicella pneumonia | Rapid deterioration risk; IV acyclovir |
| Varicella encephalitis (confusion, seizures) | IV acyclovir + ICU |
| Immunocompromised with varicella or disseminated zoster | IV acyclovir |
| Neonatal varicella | IV acyclovir |
| Zoster ophthalmicus with visual symptoms | IV antivirals + ophthalmology |
| Septic secondary bacterial infection | IV antibiotics |
| Pregnant with varicella pneumonia | High maternal mortality |
Part E: PROPHYLAXIS & PREVENTION (OPD Counselling)
Post-exposure Prophylaxis (PEP)
| Group | Intervention | Timing |
|---|
| Susceptible immunocompromised / pregnant / neonate | VZIG (Varicella-Zoster Immunoglobulin) | Within 10 days of exposure |
| Susceptible healthy adult/child (non-immune) | Varicella vaccine (if not contraindicated) | Within 3-5 days of exposure |
Vaccination
| Vaccine | Schedule | Target |
|---|
| Varicella vaccine (live attenuated Oka strain) | 2 doses: 12-15 months + 4-6 years (children); 2 doses 4-8 weeks apart (adults) | Prevention of primary varicella |
| Recombinant Zoster Vaccine (RZV/Shingrix) | 2 doses 2-6 months apart | Prevention of HZ in adults ≥50 yrs; immunocompromised from age 18+ |
| Live Zoster Vaccine (ZVL/Zostavax) | Single dose | Older recommendation; less effective than RZV |
Quick OPD Decision Summary
VARICELLA (Chickenpox)
├── Healthy child <12 yrs → Symptomatic only (calamine, paracetamol, NO aspirin)
├── Adolescent/Adult/Pregnant → Valacyclovir 1g TDS × 7d (start within 24h)
└── Immunocompromised/pneumonia/encephalitis → ADMIT, IV acyclovir
HERPES ZOSTER (Shingles)
├── Age <50, mild pain, uncomplicated → Symptomatic ± antiviral
├── Age ≥50 / moderate-severe pain → Valacyclovir 1g TDS × 7d + prednisolone
├── Ophthalmic/Ramsay Hunt → Urgent antiviral + specialist referral
└── Disseminated/encephalitis/immunocompromised → ADMIT, IV acyclovir
POST-HERPETIC NEURALGIA
└── Gabapentin/Pregabalin (first-line) + TCAs + Lidocaine patch
Sources: Fitzpatrick's Dermatology; Goldman-Cecil Medicine; Rosen's Emergency Medicine; Dermatology 2-Volume Set 5e