id.varicella-zoster.v1PRODUCTION

id.varicella-zoster.v1

Varicella zoster virus disease — primary varicella + herpes zoster + PHN + complications + RZV vaccination eligibility

infectious_diseaseacutesubacutechronicadultpediatricpregnancygeriatricneonatal

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Encounter flow

12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

VZV disease spectrum: primary varicella (chickenpox) + herpes zoster (shingles) + PHN + complications (disseminated, HZO, Ramsay Hunt, pneumonitis, encephalitis, vasculopathy, hepatitis, IRIS) + vaccine eligibility (RZV ≥ 50 routine; ≥ 19 immunocompromised; varicella vaccine 2-dose childhood + susceptible adult catch-up) (Gershon Nat Rev Dis Primers 2015; Dooling MMWR 2018)

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Set

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VZV phenotype framed (primary varicella vs zoster vs PHN vs complication vs vaccination eligibility)

Patient inputs (18)

age*demographic • CONTEXT

Age stratifies treatment (≥ 13 yo adults benefit from oral antiviral for primary varicella; ≥ 50 adults eligible for routine RZV; ≥ 60 highest PHN risk) and complication risk (Gershon Nat Rev Dis Primers 2015; Dooling MMWR 2018)

vaccination_history_varicella_and_rzv*history • CONTEXT

not present

Prior varicella vaccine + RZV / Zostavax history determines susceptibility status, post-exposure prophylaxis decisions, and future vaccination scheduling (Marin MMWR 2007; Dooling MMWR 2018)

prior_varicella_or_zoster_history*history • CONTEXT

not present

Prior varicella confers ~ 95% lifetime immunity to primary varicella but not zoster (latent reactivation); prior zoster confers some short-term immunity to recurrent zoster (~ 5% recurrence by 5 yr) but RZV vaccination still indicated after rash resolved (Cohen NEJM 2013)

pregnancy_status_and_gestational_age*history • CONTEXT

not present

Pregnancy + susceptible exposure → VariZIG within 96 h; first 20 wk → CVS risk ~ 1-2%; 5 d pre to 2 d post delivery → neonatal varicella life-threatening; severe disease (pneumonitis) → IV acyclovir; varicella vaccine CONTRAINDICATED in pregnancy (ACOG; AAP Red Book 2024)

temperature_and_systemic_symptoms*vital • CONTEXT

Fever ≥ 39 °C + systemic toxicity in primary varicella = severe disease / pneumonitis / hepatitis / encephalitis suspicion; routine fever in uncomplicated zoster less common but possible (AAP Red Book 2024)

rash_distribution_and_pattern*history • ENTRY

not present

Generalised + crops = primary varicella; dermatomal single nerve = zoster; multiple non-contiguous + immunocompromise = disseminated zoster; Hutchinson sign (nasal tip) = HZO; ear vesicles = Ramsay Hunt (Gershon Nat Rev Dis Primers 2015; Cohen NEJM 2013)

rash_onset_time*history • FRAME

not present

Antiviral benefit greatest if started ≤ 72 h of rash onset for zoster; ≤ 24 h for primary varicella in adult; new lesions still forming preserves some benefit (Cohen NEJM 2013 PMID 23863052; Gershon Nat Rev Dis Primers 2015 PMID 27188665)

cranial_nerve_or_neuro_features*symptom • RED_FLAGS

Facial palsy (Ramsay Hunt — CN VII), ophthalmoplegia (HZO with V1 + cranial nerve palsy), encephalopathy / seizures / focal deficits (encephalitis, vasculopathy + stroke pattern) (Gilden CID 2021 PMID 32856043)

oxygen_saturation*vital • RED_FLAGS

SpO2 < 94% in primary varicella or zoster + cough / dyspnoea → VZV pneumonitis (especially adult, pregnant, immunocompromised); CXR + IV acyclovir (Gershon Nat Rev Dis Primers 2015)

immunocompromise_status*history • RISK_STRATIFICATION

HIV (CD4 < 200), transplant (within 1 yr OR ongoing immunosuppression), chemo (cycle nadir), high-dose chronic steroid (≥ 20 mg prednisone-equivalent × ≥ 1 mo), autoimmune on biologic — all raise dissemination risk + lower threshold for IV acyclovir (Gilden CID 2021; AAP Red Book 2024)

pain_assessment_neuropathic_features*symptom • TREATMENT

Neuritic pain in dermatome before or with rash = acute zoster pain; persistent ≥ 3 mo = PHN; allodynia / hyperalgesia in PHN; pain intensity (NRS 0-10) drives ladder choice (Dworkin CID 2007 PMID 17143845)

creatinine_and_renal_function*lab • TREATMENT

Baseline + serial during IV acyclovir for crystalline nephropathy monitoring; dose-adjust if AKI; pregabalin / gabapentin renal dose adjust (FDA labels)

lft_for_hepatitis_assessmentlab • BRANCHING_WORKUP

AST/ALT 2-10× ULN in disseminated VZV / pneumonitis / immunocompromised — VZV hepatitis component; baseline for antiviral hepatic monitoring (AAP Red Book 2024)

chest_xray_if_respiratoryimaging • BRANCHING_WORKUP

not present

CXR if respiratory features in primary varicella or zoster — VZV pneumonitis = diffuse infiltrates; especially adult, pregnant, immunocompromised (Gershon Nat Rev Dis Primers 2015)

mri_brain_if_neuro_featuresimaging • BRANCHING_WORKUP

not present

MRI for VZV encephalitis (temporal lobe + insular involvement classic — overlap with HSV encephalitis); vasculopathy (multifocal infarcts especially in HIV / immunocompromised) (Gilden CID 2021 PMID 32856043)

slit_lamp_eye_exam_if_hzoimaging • BRANCHING_WORKUP

not present

Slit-lamp + fluorescein staining + intraocular pressure if HZO suspected — corneal involvement (pseudo-dendrites, stromal keratitis), uveitis, glaucoma; emergent ophthalmology (AAO HZO PPP)

vzv_serology_igg_for_immunitylab • CONTEXT

VZV IgG for IMMUNITY testing (vaccination decisions, pregnant susceptibility assessment, post-exposure prophylaxis stratification) — NOT for acute disease diagnosis (cross-reactivity + slow seroconversion) (Marin MMWR 2007)

vzv_pcr_vesicle_swab_or_csf_or_bloodlab • INITIAL_WORKUP

VZV PCR (vesicle base swab, CSF for neuro, blood for disseminated / immunocompromised) — LR+ > 100, specificity ~ 100%; reserved for atypical / immunocompromised / vasculopathy diagnosis (Cohen NEJM 2013; Gilden CID 2021)

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (10)

10 need judgement

informationallife_threateningdisseminated_zoster_or_pneumonitis
Disseminated zoster (> 20 lesions outside primary + 2 adjacent dermatomes) OR VZV pneumonitis (SpO2 < 94% + diffuse infiltrates on CXR) — life-threatening; IV acyclovir 10 mg/kg q8h × 7-14 d + ICU + ID consult; bacterial co-empirics until alternative source excluded if sepsis-like (Gilden CID 2021 PMID 32856043; AAP Red Book 2024)
Trigger could not be auto-evaluated — needs clinician judgement.
informationallife_threateningvzv_encephalitis_or_vasculopathy
VZV encephalitis (altered mental status, seizures, focal deficits + CSF lymphocytic pleocytosis + positive VZV PCR OR intrathecal antibody index) OR VZV vasculopathy (focal neuro deficits + stroke pattern on MRI + recent zoster + positive CSF VZV PCR or antibody index) — life-threatening; IV acyclovir 15 mg/kg q8h × 14 d + steroids for vasculopathy + neurology + ID (Gilden CID 2021 PMID 32856043; IDSA HSV-VZV)
Trigger could not be auto-evaluated — needs clinician judgement.
informationallife_threateningneonatal_varicella_exposure_5_days_pre_to_2_days_post_delivery
Maternal varicella 5 d pre to 2 d post delivery — life-threatening neonatal varicella (mortality up to 30% without VariZIG); VariZIG immediately + IV acyclovir 10 mg/kg q8h if symptomatic + NICU admission + ID consult; bacterial co-empirics until alternative source excluded (AAP Red Book 2024; CDC VariZIG guidance)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalsevereophthalmic_zoster_hutchinson_sign
Vesicle on nasal tip (Hutchinson sign) in V1 trigeminal distribution — corneal-involvement risk (nasociliary branch V1); EMERGENT ophthalmology + oral valacyclovir 1 g TID × 7-10 d + topical antiviral (trifluridine or ganciclovir gel) + slit-lamp / IOP / fluorescein staining; lifetime ocular complications (keratitis, uveitis, glaucoma) (AAO HZO PPP; Cohen NEJM 2013 PMID 23863052)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalsevereramsay_hunt_syndrome
Facial palsy + ear vesicles + auricular pain ± auditory/vestibular features — zoster oticus; oral valacyclovir 1 g TID × 7-10 d + prednisone 60 mg/d × 5 d then taper; neurology + ENT consult; facial recovery prognosis worse than Bell palsy idiopathic (~ 40% complete recovery vs ~ 70%) (Sweeney JNNP 2001; Dworkin CID 2007 PMID 17143845)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalseverepregnant_with_varicella_exposure_susceptible
Susceptible pregnant patient (any trimester) exposed to varicella within 96 h (CDC expanded to 10 d) — VariZIG 125 IU per 10 kg (max 625 IU) IM + VZV IgG serology testing; if active disease, treat per phenotype (oral acyclovir if mild / IV acyclovir if severe pneumonitis); congenital varicella syndrome risk ~ 1-2% if maternal varicella in first 20 wk gestation; vaccination CONTRAINDICATED in pregnancy (ACOG; AAP Red Book 2024; CDC VariZIG guidance)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalsevereimmunocompromised_zoster_or_varicella
Zoster or primary varicella in immunocompromised (HIV CD4 < 200, transplant within 1 yr OR ongoing immunosuppression, chemo cycle nadir, chronic high-dose steroid ≥ 20 mg prednisone-equivalent × ≥ 1 mo, autoimmune on biologic) — IV acyclovir 10 mg/kg q8h × 7-14 d + ID consult; foscarnet 40 mg/kg q8h IV rescue if acyclovir resistance suspected; risk of dissemination, pneumonitis, encephalitis, hepatitis, IRIS especially in HIV / transplant (AAP Red Book 2024; IDSA HSV-VZV)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalmoderatephn_severe_persistent_pain_at_3_months
Post-herpetic neuralgia — neuropathic pain (allodynia, hyperalgesia, burning) ≥ 3 months in healed zoster dermatome; pain ladder gabapentin / pregabalin / TCA / topical lidocaine / capsaicin / opioids if severe + pain medicine referral if refractory; refractory: nerve block / neurostimulation (Dworkin CID 2007 PMID 17143845; AAN 2004 PHN guideline)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalmildvaccination_eligible_adult_50plus
Adult ≥ 50 — RZV (Shingrix) 2-dose series 2-6 mo apart routine per ACIP 2018; irrespective of prior varicella, prior zoster (after rash resolved), or prior Zostavax history (≥ 2 mo after Zostavax); ~ 97% efficacy ZOE-50, ~ 91% ZOE-70; replaces Zostavax (no longer available US since 11/2020) (Dooling MMWR 2018 PMID 29370152; Lal NEJM 2015 PMID 25916341; Cunningham NEJM 2016 PMID 27626517)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalmildvaccination_eligible_immunocompromised_19plus
Adult ≥ 19 with immunocompromise (HIV, transplant, autoimmune on immunosuppression, hematologic malignancy on therapy, chronic high-dose steroid) — RZV (Shingrix) 2-dose series per ACIP 2022; RZV is recombinant subunit (NOT live attenuated) — broadly safe in immunocompromised; efficacy ~ 70-90% across cohorts (Anderson MMWR 2022 PMID 35051134)
Trigger could not be auto-evaluated — needs clinician judgement.

Workflow calculators

This dossier does not reference any calculators.

Recommended regimen

VZV antiviral therapy — by phenotype (primary varicella / zoster / severe / HZO / Ramsay Hunt / disseminated / pregnant / neonatal)

axis: vzv_antiviral_by_phenotypestep primary_varicella_pediatric_supportive - Primary varicella in immunocompetent pediatric < 13 yo — supportive only, NO routine antiviral

Selected step "Primary varicella in immunocompetent pediatric < 13 yo — supportive only, NO routine antiviral" — Immunocompetent child < 13 yo with primary varicella (generalised crops + fever + pruritus); not pregnant, not immunocompromised, no complications

acetaminophen
first line
analgesic_antipyretic
10-15 mg/kg/dose q4-6h PRN (max 75 mg/kg/d) • PO • q4-6h PRN
triggers: fever_pediatric, pruritus_pediatric
Acetaminophen preferred — AVOID aspirin (Reye syndrome); AVOID ibuprofen (emerging necrotising fasciitis signal with secondary streptococcal infection per AAP) (AAP Red Book 2024)
rxcui 161

outpatient playbook — drug actions (11)

1. valacyclovir PO (uncomplicated zoster)
1 g PO TID × 7 days • PO • TID
trigger: Uncomplicated zoster + within 72 h of rash + immunocompetent
First-line oral antiviral for uncomplicated zoster (Cohen NEJM 2013 PMID 23863052)
2. famciclovir PO (alternative)
500 mg PO TID × 7 days • PO • TID
trigger: Valacyclovir alternative
Equally effective; renal dose adjust if CrCl < 60 (FDA label)
3. acyclovir PO (cost alternative)
800 mg PO 5×/day × 7 days • PO • 5×/day
trigger: Cost-effective alternative
Cost-effective; worse compliance with 5×/d (Cohen NEJM 2013)
4. acyclovir PO (adult primary varicella + within 24 h)
800 mg PO 5×/day × 5-7 days • PO • 5×/day
trigger: Adult primary varicella + immunocompetent + within 24 h
Reduces severity + duration (Gershon Nat Rev Dis Primers 2015 PMID 27188665)
5. gabapentin (PHN first-line)
300 mg HS, titrate to 900-3600 mg/d divided TID • PO • TID
trigger: PHN persistent neuropathic pain ≥ 3 mo
AAN 2004 + Dworkin CID 2007 — first-line for PHN; titrate over 1-2 wk
6. pregabalin (PHN alternative)
75 mg BID, titrate to 150-300 mg/d • PO • BID-TID
trigger: Gabapentin alternative or compliance concern
Linear pharmacokinetics + BID dosing (Dworkin CID 2007)
7. topical lidocaine 5% patch (PHN)
Up to 3 patches × 12 h on / 12 h off • topical • 12 h on / 12 h off
trigger: PHN localised dermatome allodynia
Minimal systemic absorption; well-tolerated in elderly (FDA label)
8. capsaicin 8% patch (PHN refractory)
In-office application × 60 min; repeat q3 mo PRN • topical • q3 mo PRN
trigger: PHN refractory to first-line + topical lidocaine
Substance P depletion; in-office only (FDA label — Qutenza)
9. RZV (Shingrix) — vaccination
0.5 mL IM × 2 doses 2-6 mo apart • IM • 2-dose series 2-6 mo apart
trigger: Age ≥ 50 routine OR age ≥ 19 immunocompromised — irrespective of prior varicella, prior zoster (after rash resolved), or prior Zostavax history (≥ 2 mo after Zostavax)
Dooling MMWR 2018 PMID 29370152 + Anderson MMWR 2022 PMID 35051134; ~ 97% efficacy ZOE-50 PMID 25916341, ~ 91% ZOE-70 PMID 27626517; ~ 70-90% in immunocompromised cohorts; reactogenicity common but rarely serious; replaces Zostavax
10. varicella vaccine (2-dose susceptible adult catch-up OR pediatric 2-dose schedule)
0.5 mL SC × 2 doses • SC • Adult: dose 1 + dose 2 at 4-8 wk; pediatric: 12-15 mo + 4-6 yr
trigger: Susceptible immunocompetent adult catch-up OR routine pediatric immunization
Marin MMWR 2007 PMID 17585291; > 95% efficacy against severe disease; CONTRAINDICATED in pregnancy + severe immunocompromise (live attenuated)
11. VariZIG (post-exposure prophylaxis)
125 IU per 10 kg (max 625 IU) IM • IM • single dose within 96 h (CDC expanded to 10 d)
trigger: High-risk susceptible exposed: immunocompromised, pregnant, neonatal (maternal varicella 5 d pre to 2 d post delivery)
CDC; AAP Red Book 2024; ACOG — reduces neonatal varicella mortality from ~ 30% to < 5%

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: Generalized vesicular rash in successive crops (papule → vesicle → pustule → crust) + fever + pruritus — primary varicella (Gershon Nat Rev Dis Primers 2015 PMID 27188665; AAP Red Book 2024); Dermatomal vesicular rash + neuritic pain along single dermatome (occasionally 2-3 contiguous) — herpes zoster (Cohen NEJM 2013 PMID 23863052); Vesicle on nasal tip (Hutchinson sign) in V1 distribution — ophthalmic zoster (HZO) with corneal-involvement risk → emergent ophthalmology (AAO HZO PPP; Cohen NEJM 2013).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Varicella zoster virus disease — primary varicella + herpes zoster + PHN + complications + RZV vaccination eligibility** (id.varicella-zoster.v1).
Phenotype framing: Primary varicella vs HFMD (coxsackievirus — palms + soles), drug eruption (DRESS, SJS), bullous impetigo, eczema herpeticum (HSV in atopic), HFMD vs varicella in young child. Zoster vs HSV (recurrent labialis / genitalis non-dermatomal), contact dermatitis, bullous insect bite, dermatomal nerve compression with rash. Ramsay Hunt vs Bell palsy idiopathic. HZO vs orbital cellulitis, periorbital cellulitis, contact dermatitis. PHN vs other neuropathic pain (diabetic neuropathy, trigeminal neuralgia). VZV encephalitis vs HSV encephalitis (HSV more common; empiric IV acyclovir covers both pending PCR) (Gershon Nat Rev Dis Primers 2015; Cohen NEJM 2013)
Scope: VZV disease spectrum: primary varicella (chickenpox) + herpes zoster (shingles) + PHN + complications (disseminated, HZO, Ramsay Hunt, pneumonitis, encephalitis, vasculopathy, hepatitis, IRIS) + vaccine eligibility (RZV ≥ 50 routine; ≥ 19 immunocompromised; varicella vaccine 2-dose childhood + susceptible adult catch-up) (Gershon Nat Rev Dis Primers 2015; Dooling MMWR 2018)

No severity triggers fired against current inputs.

Plan

Regimen axis: **VZV antiviral therapy — by phenotype (primary varicella / zoster / severe / HZO / Ramsay Hunt / disseminated / pregnant / neonatal)** — step "Primary varicella in immunocompetent pediatric < 13 yo — supportive only, NO routine antiviral".
1. acetaminophen 10-15 mg/kg/dose q4-6h PRN (max 75 mg/kg/d) PO q4-6h PRN (analgesic_antipyretic, first line) — Acetaminophen preferred — AVOID aspirin (Reye syndrome); AVOID ibuprofen (emerging necrotising fasciitis signal with secondary streptococcal infection per AAP) (AAP Red Book 2024)

Setting playbook (outpatient) — Manage uncomplicated zoster on oral antivirals; primary varicella in immunocompetent child supportive care; PHN management ladder + pain medicine referral; post-exposure prophylaxis for susceptible contacts; vaccination reconciliation (RZV ≥ 50 routine + ≥ 19 immunocompromised + varicella 2-dose susceptible adult catch-up + pediatric 2-dose schedule audit) (Dooling MMWR 2018; Cohen NEJM 2013)
2. valacyclovir PO (uncomplicated zoster) 1 g PO TID × 7 days PO TID — Uncomplicated zoster + within 72 h of rash + immunocompetent (First-line oral antiviral for uncomplicated zoster (Cohen NEJM 2013 PMID 23863052))
3. famciclovir PO (alternative) 500 mg PO TID × 7 days PO TID — Valacyclovir alternative (Equally effective; renal dose adjust if CrCl < 60 (FDA label))
4. acyclovir PO (cost alternative) 800 mg PO 5×/day × 7 days PO 5×/day — Cost-effective alternative (Cost-effective; worse compliance with 5×/d (Cohen NEJM 2013))
5. acyclovir PO (adult primary varicella + within 24 h) 800 mg PO 5×/day × 5-7 days PO 5×/day — Adult primary varicella + immunocompetent + within 24 h (Reduces severity + duration (Gershon Nat Rev Dis Primers 2015 PMID 27188665))
6. gabapentin (PHN first-line) 300 mg HS, titrate to 900-3600 mg/d divided TID PO TID — PHN persistent neuropathic pain ≥ 3 mo (AAN 2004 + Dworkin CID 2007 — first-line for PHN; titrate over 1-2 wk)
7. pregabalin (PHN alternative) 75 mg BID, titrate to 150-300 mg/d PO BID-TID — Gabapentin alternative or compliance concern (Linear pharmacokinetics + BID dosing (Dworkin CID 2007))
8. topical lidocaine 5% patch (PHN) Up to 3 patches × 12 h on / 12 h off topical 12 h on / 12 h off — PHN localised dermatome allodynia (Minimal systemic absorption; well-tolerated in elderly (FDA label))
9. capsaicin 8% patch (PHN refractory) In-office application × 60 min; repeat q3 mo PRN topical q3 mo PRN — PHN refractory to first-line + topical lidocaine (Substance P depletion; in-office only (FDA label — Qutenza))
10. RZV (Shingrix) — vaccination 0.5 mL IM × 2 doses 2-6 mo apart IM 2-dose series 2-6 mo apart — Age ≥ 50 routine OR age ≥ 19 immunocompromised — irrespective of prior varicella, prior zoster (after rash resolved), or prior Zostavax history (≥ 2 mo after Zostavax) (Dooling MMWR 2018 PMID 29370152 + Anderson MMWR 2022 PMID 35051134; ~ 97% efficacy ZOE-50 PMID 25916341, ~ 91% ZOE-70 PMID 27626517; ~ 70-90% in immunocompromised cohorts; reactogenicity common but rarely serious; replaces Zostavax)
11. varicella vaccine (2-dose susceptible adult catch-up OR pediatric 2-dose schedule) 0.5 mL SC × 2 doses SC Adult: dose 1 + dose 2 at 4-8 wk; pediatric: 12-15 mo + 4-6 yr — Susceptible immunocompetent adult catch-up OR routine pediatric immunization (Marin MMWR 2007 PMID 17585291; > 95% efficacy against severe disease; CONTRAINDICATED in pregnancy + severe immunocompromise (live attenuated))
12. VariZIG (post-exposure prophylaxis) 125 IU per 10 kg (max 625 IU) IM IM single dose within 96 h (CDC expanded to 10 d) — High-risk susceptible exposed: immunocompromised, pregnant, neonatal (maternal varicella 5 d pre to 2 d post delivery) (CDC; AAP Red Book 2024; ACOG — reduces neonatal varicella mortality from ~ 30% to < 5%)

Non-pharmacologic actions:
- School / workplace exclusion until all lesions crusted (primary varicella); cover rash + good hand hygiene for localised zoster (especially in healthcare workers)
- Tick / exposure prevention counseling (vaccination is the primary prevention)
- Outpatient pain medicine referral for PHN refractory to first-line agents at 3 mo
- Outpatient ophthalmology follow-up for HZO long-term (keratitis / uveitis / glaucoma lifetime risk)
- Outpatient neuro / ENT follow-up for Ramsay Hunt (facial recovery tracking + audiology)
- Outpatient ID follow-up if immunocompromised (HIV CD4 / antiretroviral coordination; transplant ID consultation)
- Outpatient obstetrics follow-up if pregnant (fetal surveillance; vaccination plan postpartum)
- Family + caregiver education on return precautions (new neuro signs, ocular symptoms, respiratory distress, new disseminated rash)
- Vaccination reconciliation at every visit until catch-up complete
- Public health reporting if institutional outbreak (school, healthcare facility, congregate setting)

AVOID / contraindication checks:
- Acyclovir iv hydration prevent crystal nephropathy (FDA label; Gilden CID 2021)
- Acyclovir dose adjust aki (Cr × 1.5 2 → q12h; Cr × 2 3 → q24h per FDA label)
- Foscarnet nephrotoxicity electrolyte monitoring (FDA label; reserve for documented acyclovir resistance)
- Varicella vaccine contraindicated pregnancy immunocompromised severe (CDC ACIP; AAP Red Book 2024 — live attenuated vaccine)
- Rzv shingrix not live vaccine acceptable in immunocompromised (Dooling MMWR 2018; Anderson MMWR 2022 — recombinant subunit)
- Zostavax no longer available us since 2020 11 (CDC; Dooling MMWR 2018 — replaced by RZV)
- Avoid aspirin in varicella reye syndrome (AAP Red Book 2024; FDA label)
- Avoid ibuprofen in varicella emerging necrotising fasciitis signal (AAP Red Book 2024 caution)
- Varizig within 96h cdc expanded to 10d for high risk susceptible (CDC; AAP Red Book 2024)
- Famciclovir dose adjust if crcl lt 60 (FDA label)
- Valacyclovir dose adjust if renal impairment (FDA label)
- Rzv reactogenicity injection site systemic counsel (Lal NEJM 2015; Cunningham NEJM 2016)
- Rzv rare gbs signal still under fda monitoring benefit outweighs (FDA 2021)
- Tca anticholinergic falls risk in elderly (AGS Beers Criteria 2023; PHN nortriptyline)
- Tca qt prolongation baseline ecg in older adults (FDA label; PHN nortriptyline)
- Pregabalin and gabapentin dose adjust for renal impairment (FDA labels; PHN)
- Capsaicin 8 percent patch in office only application (FDA label — Qutenza; PHN)
- Lidocaine 5 percent patch 12h on 12h off max 3 patches (FDA label; PHN)
- Opioids last line in phn due to dependence and falls risk (CDC opioid guideline 2022; PHN)

Monitoring

Regimen monitoring:
- Serial creatinine + UOP during IV acyclovir (crystalline nephropathy prevention; IV hydration 1.5-2× maintenance)
- LFT trend if hepatitis component (disseminated form) — q24-48h initially
- New lesions ceased forming by day 3-5 on antivirals — failure to do so → reassess for resistance / immunocompromise / alternative diagnosis
- Daily ophthalmology slit-lamp + IOP if HZO with corneal involvement (lifetime risk of keratitis / uveitis / glaucoma)
- Audiology + facial recovery tracking if Ramsay Hunt (~ 40% complete recovery vs ~ 70% Bell palsy)
- CSF VZV PCR + intrathecal antibody index follow-up if vasculopathy (some centres at d 14)
- PHN ladder: pain scale (NRS 0-10) at every visit + dose-titrate q1-2 wk + functional restoration
- Renal function q3-6 mo if on gabapentin / pregabalin (dose adjust if CrCl drops)
- Falls risk assessment in elderly on TCA / gabapentinoid / opioid components (PHN)
- Mood / depression screen (chronic pain + depression bidirectional — PHN)
- Pain medicine referral if PHN refractory to 2-3 first-line agents + topical adjuncts at 3 mo
- RZV dose 2 at 2-6 mo after dose 1 — do NOT restart if > 6 mo (give dose 2 ASAP)
- Varicella vaccine dose 2 at 4-8 wk after dose 1 (post-exposure or catch-up) — track to completion

Setting (outpatient) monitoring:
- Rash resolution at 1-2 wk for primary varicella + zoster
- PHN surveillance at 1 mo, 3 mo (PHN diagnostic threshold), 6 mo, 12 mo
- Ophthalmology long-term if HZO
- Facial recovery tracking if Ramsay Hunt
- RZV dose 2 at 2-6 mo after dose 1
- Varicella vaccine dose 2 at 4-8 wk after dose 1 (adult catch-up) OR 4-6 yr (pediatric schedule)
- Pain scale + functional restoration if PHN
- Renal function q3-6 mo if on gabapentin / pregabalin chronic

Follow-up plan: Post-zoster: PHN surveillance at 1 mo, 3 mo (PHN diagnostic threshold), 6 mo; pain medicine + neurology if refractory. Post-HZO: ophthalmology lifetime follow-up for keratitis / uveitis / glaucoma recurrence. Post-Ramsay Hunt: facial recovery tracking (~ 40% complete recovery vs ~ 70% for Bell palsy) + audiology + ENT. Post-vasculopathy: stroke prevention + cerebrovascular follow-up. Vaccination reconciliation: RZV 2-dose ≥ 50 routine / ≥ 19 immunocompromised; varicella vaccine 2-dose susceptible adult catch-up; pediatric 2-dose schedule audit (12-15 mo + 4-6 yr). Family education + contact tracing if institutional outbreak; report to public health if needed.
- Close-out criterion: Follow-up + vaccination plan + PHN ladder set; education delivered

Monitoring phase: Outpatient zoster: rash resolution expected 1-2 wk; new lesions cease forming 3-5 d on antivirals; return precautions for new neuro / ophthalmic / disseminated features. Inpatient / ICU: serial creatinine + UOP for acyclovir crystalline nephropathy; LFT trend if hepatitis; daily reassessment of antiviral duration; CSF VZV PCR follow-up if vasculopathy (some centres at d 14). PHN: pain scale (NRS) at every visit; dose-titrate gabapentinoid or TCA; pain medicine referral if refractory. Vaccination tracking: dose 2 of RZV at 2-6 mo after dose 1 (do NOT restart if > 6 mo — give dose 2 ASAP).

Disposition

Current setting: outpatient — Manage uncomplicated zoster on oral antivirals; primary varicella in immunocompetent child supportive care; PHN management ladder + pain medicine referral; post-exposure prophylaxis for susceptible contacts; vaccination reconciliation (RZV ≥ 50 routine + ≥ 19 immunocompromised + varicella 2-dose susceptible adult catch-up + pediatric 2-dose schedule audit) (Dooling MMWR 2018; Cohen NEJM 2013)

Disposition criteria:
- Sustained recovery — rash resolved + pain controlled + functional restoration + vaccination plan in progress + family education delivered + outpatient follow-up scheduled with sub-specialty as indicated

Escalation triggers (move to higher acuity):
- New neuro signs (focal deficits, seizures, encephalopathy) → urgent ED + MRI + LP + IV acyclovir
- New respiratory distress / SpO2 < 94% → urgent ED + CXR + IV acyclovir
- New ocular pain / vision change → emergent ophthalmology
- New systemic toxicity / disseminated rash → urgent ED + ID + IV acyclovir
- Severe refractory PHN ≥ 6 mo → pain medicine + neurology + consider nerve block / neurostimulation
- Immunocompromise emergence (new HIV diagnosis, transplant, chemo, high-dose steroid initiation) → re-evaluate antiviral threshold + RZV vaccination planning

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Disseminated zoster (> 20 lesions outside primary + 2 adjacent dermatomes) OR VZV pneumonitis (SpO2 < 94% + diffuse infiltrates on CXR) — life-threatening; IV acyclovir 10 mg/kg q8h × 7-14 d + ICU + ID consult; bacterial co-empirics until alternative source excluded if sepsis-like (Gilden CID 2021 PMID 32856043; AAP Red Book 2024)
- [LIFE_THREATENING] VZV encephalitis (altered mental status, seizures, focal deficits + CSF lymphocytic pleocytosis + positive VZV PCR OR intrathecal antibody index) OR VZV vasculopathy (focal neuro deficits + stroke pattern on MRI + recent zoster + positive CSF VZV PCR or antibody index) — life-threatening; IV acyclovir 15 mg/kg q8h × 14 d + steroids for vasculopathy + neurology + ID (Gilden CID 2021 PMID 32856043; IDSA HSV-VZV)
- [LIFE_THREATENING] Maternal varicella 5 d pre to 2 d post delivery — life-threatening neonatal varicella (mortality up to 30% without VariZIG); VariZIG immediately + IV acyclovir 10 mg/kg q8h if symptomatic + NICU admission + ID consult; bacterial co-empirics until alternative source excluded (AAP Red Book 2024; CDC VariZIG guidance)

Citations

- CDC ACIP — Recombinant Zoster Vaccine (RZV/Shingrix) (Dooling MMWR 2018 + Anderson MMWR 2022 immunocompromised) + CDC ACIP Varicella vaccination (Marin MMWR 2007) + AAP Red Book current edition (2024 + 2026 floor) Varicella + Herpes Zoster chapters + IDSA HSV-VZV consensus / Dworkin CID 2007 + Cohen NEJM 2013 Herpes Zoster review + Gershon Nat Rev Dis Primers 2015 Varicella Zoster Virus Infection + Gilden/Ansari CID 2021 severe VZV CNS vasculopathy + Lal NEJM 2015 ZOE-50 + Cunningham NEJM 2016 ZOE-70 + ACOG Practice Advisory Varicella in Pregnancy + AAO HZO Preferred Practice Pattern + CDC VariZIG guidance [PMID:25916341](https://pubmed.ncbi.nlm.nih.gov/25916341/)
- Cited evidence (PMID 27626517) [PMID:27626517](https://pubmed.ncbi.nlm.nih.gov/27626517/)
- Cited evidence (PMID 29370152) [PMID:29370152](https://pubmed.ncbi.nlm.nih.gov/29370152/)
- Cited evidence (PMID 35051134) [PMID:35051134](https://pubmed.ncbi.nlm.nih.gov/35051134/)
- Cited evidence (PMID 17585291) [PMID:17585291](https://pubmed.ncbi.nlm.nih.gov/17585291/)

Last reconciled with current guidelines: 2026-05-22.

References

CDC ACIP — Recombinant Zoster Vaccine (RZV/Shingrix) (Dooling MMWR 2018 + Anderson MMWR 2022 immunocompromised) + CDC ACIP Varicella vaccination (Marin MMWR 2007) + AAP Red Book current edition (2024 + 2026 floor) Varicella + Herpes Zoster chapters + IDSA HSV-VZV consensus / Dworkin CID 2007 + Cohen NEJM 2013 Herpes Zoster review + Gershon Nat Rev Dis Primers 2015 Varicella Zoster Virus Infection + Gilden/Ansari CID 2021 severe VZV CNS vasculopathy + Lal NEJM 2015 ZOE-50 + Cunningham NEJM 2016 ZOE-70 + ACOG Practice Advisory Varicella in Pregnancy + AAO HZO Preferred Practice Pattern + CDC VariZIG guidance — PMID:25916341
Cited evidence (PMID 27626517) — PMID:27626517
Cited evidence (PMID 29370152) — PMID:29370152
Cited evidence (PMID 35051134) — PMID:35051134
Cited evidence (PMID 17585291) — PMID:17585291