Suspected eczema herpeticum
Eczema or other skin-barrier disease with new painful, clustered vesicles or punched-out erosions, often with fever. Adults and children.
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DermatologyEmergency
Eczema Herpeticum (Kaposi Varicelliform Eruption)
Eczema Herpeticum (Kaposi Varicelliform Eruption): Suspected eczema herpeticum → Emergency: start antiviral today, before test results → Clinical featur...
Pathway Overview
17 steps
Algorithm Steps
17 total
01Start 02Warning Emergency: start antiviral today, before test results
Each day of delay in aciclovir prolongs illness. Complications: HSV keratitis, encephalitis, S. aureus bacteraemia.
- Do not wait for HSV PCR results to start antiviral
- Lesions on or around the eyes: same-day ophthalmology review
- Infant under 3 months, immunocompromised or neurological signs: IV aciclovir and admit
03Action Clinical features
Diagnosis is clinical. Bacterial infection often coexists.
- Monomorphic clustered vesicles or pustules; punched-out erosions with haemorrhagic crusts
- On eczematous skin; most often face and neck
- Painful rather than itchy; fever, malaise, lymphadenopathy
- Differentials: bacterial infection of eczema, impetigo, eczema coxsackium, varicella
04Action Who is at risk
Disrupted skin barrier lets HSV spread.
- Atopic dermatitis (most common), especially moderate to severe or poorly controlled
- Previous eczema herpeticum (recurrence is common)
- Other barrier diseases: Darier disease, pemphigus, ichthyosis, burns, cutaneous T-cell lymphoma
- JAK inhibitor or other systemic immunosuppression increases risk
05Action Tests: swab for HSV PCR, then start antiviral
Take the swab, then give the first antiviral dose without waiting for the result.
- Unroof a vesicle and swab the base for HSV PCR (test of choice)
- Add enterovirus PCR if eczema coxsackium is possible; bacterial swab for culture
- Tzanck smear and viral culture are slower and less sensitive; use only if PCR is not available
- Unwell or IV treatment planned: FBC, UEC (creatinine before IV aciclovir), LFT, blood culture if febrile
06Warning High-risk patient: treat as severe (IV aciclovir, admit)
Infant under 3 months (neonate under 28 days: neonatal HSV guideline); immunocompromised, or on a JAK inhibitor or other systemic immunosuppressant; headache, confusion, seizure or neck stiffness.
- Infant under 3 months: paediatric team; assess for disseminated and CNS HSV. Neonate under 28 days: neonatal HSV work-up incl. LP; IV aciclovir at least 14 days (21 days if CNS or disseminated)
- Neurological signs: manage as HSV encephalitis (encephalitis doses; CSF HSV PCR)
- Immunocompromised: longer course; ask the specialist before stopping the immunosuppressant
07Warning Lesions on eyelids or around the eye: same-day ophthalmology
HSV keratitis threatens vision.
- Ask about eye pain, photophobia, watering, reduced vision
- Fluorescein: a dendritic ulcer means HSV keratitis
- No corticosteroid in or around the eye unless ophthalmology advises
08Decision Any severe feature?
Severe: fever or unwell, widespread lesions or more than 1 body region, eye involvement, neurological signs, cannot take oral medicine or fluids, or a high-risk patient.
- If Yes
09Action Severe: admit for IV aciclovir
Infuse each dose over at least 1 hour. Keep well hydrated. Check creatinine; avoid other nephrotoxic drugs.
- Adult: aciclovir 5 mg/kg IV 8-hourly; 10 mg/kg IV 8-hourly if encephalitis or disseminated (organ) disease
- Child 3 months to 18 years: aciclovir 10 mg/kg (max 750 mg) IV 8-hourly
- Child under 12 years with encephalitis or disseminated disease: 20 mg/kg (max 750 mg) IV 8-hourly
- Infant under 3 months (corrected age): 20 mg/kg IV 8-hourly (under 30 weeks corrected gestation: 12-hourly); neonatal or paediatric team
- Obese: dose on ideal body weight
- Renal impairment (CrCl or eGFR mL/min): 25-50 same dose 12-hourly; 10-25 same dose 24-hourly; under 10 half dose 24-hourly
- Switch to oral when improving and able to take oral. Total 7 days; immunocompromised 7-14 days or until healed; encephalitis 14-21 days; neonate under 28 days at least 14 days IV
10Action Skin care and pain relief (all patients)
Once the antiviral has started, continue eczema treatment on active eczema.
- Paracetamol for pain. Avoid NSAIDs if dehydrated, in renal impairment or on IV aciclovir
- Gentle cleansing and antiseptic wash (for example dilute bleach bath or chlorhexidine); emollient
- Topical corticosteroid may continue on active eczema once the antiviral has started (no harm shown); avoid systemic corticosteroid
- Remove crusts gently before applying topical treatment
- HSV spreads by contact: hand hygiene, cover lesions, keep away from newborns and people with eczema; in hospital, contact precautions until lesions are dry and crusted
11Decision Signs of secondary bacterial infection?
Yellow crusts, pus, spreading redness or warmth, new fever, or signs of sepsis.
- If Yes
12Action Bacterial infection: swab and add antibiotic
Usually S. aureus or Streptococcus pyogenes. Sepsis signs: blood culture, IV antibiotics, sepsis pathway. Severe (immediate) penicillin allergy: no cefalexin or cefazolin; use clindamycin.
- Child: cefalexin 20 mg/kg (max 750 mg) orally 8-hourly for 5 days
- Adult: cefalexin 500 mg orally 6-hourly for 5 days
- MRSA risk (previous MRSA, northern or remote Australia), child: trimethoprim-sulfamethoxazole 4/20 mg/kg (max 160/800 mg) orally 12-hourly, or clindamycin 10 mg/kg (max 450 mg) orally 6-hourly
- MRSA risk, adult: trimethoprim-sulfamethoxazole 160/800 mg, 1-2 tablets orally 12-hourly, or doxycycline 100 mg orally 12-hourly
- Doxycycline: not in pregnancy or under 8 years. Trimethoprim-sulfamethoxazole: not under 2 months; avoid in pregnancy if possible
- Cellulitis needing IV: cefazolin (child 50 mg/kg, max 2 g; adult 2 g) IV 8-hourly; MRSA risk: add vancomycin
- Severe penicillin allergy: clindamycin orally (child 10 mg/kg, max 450 mg, 6-hourly; adult 300-450 mg 6-hourly); if IV needed, clindamycin (child 10 mg/kg, max 600 mg, 6-hourly; adult 600 mg 8-hourly) or vancomycin
13Action Review at 24-48 hours
Check the response to the antiviral and look again for eye, neurological and bacterial complications.
- Not improving or new lesions despite antiviral: recheck the diagnosis (bacterial infection, eczema coxsackium) and adherence
- Immunocompromised and not responding: consider aciclovir-resistant HSV; send resistance testing; infectious diseases advice
- Complete the full antiviral course even if improved
14Decision Improving on treatment?
Fewer new lesions, fever settling, eating and drinking.
- If Yes
15Outcome Improving: complete treatment and prevent recurrence
Complete the antiviral course. Teach the early signs: about half of patients have another episode. GP or dermatology follow-up in 1-2 weeks to optimise eczema control.
- Lesions usually heal over 2-6 weeks
- Seek same-day care if early signs recur
- Frequent recurrence: dermatology review for suppressive or stand-by valaciclovir
- If systemic eczema therapy is needed after eczema herpeticum: dupilumab preferred; use JAK inhibitors with caution
If No16Action Not improving or complications: escalate
Admit (or escalate) and give IV aciclovir if not already on it.
- Eye symptoms: urgent ophthalmology
- Headache, confusion, seizure or neck stiffness: HSV encephalitis pathway
- Sepsis or bacteraemia: IV antibiotics and sepsis pathway
- No response in an immunocompromised patient: infectious diseases advice (aciclovir resistance, foscarnet)
If No- Path rejoins step 13Shared downstream outcome
If No17Action Not severe: oral antiviral, review in 24-48 hours
Localised lesions, well, eating and drinking, and reliable review. Infants under 3 months and high-risk patients do not take this path.
- Adult: valaciclovir 1 g orally 8-hourly, or aciclovir 800 mg orally 5 times daily
- Child 3 months or older: aciclovir 10 mg/kg (max 200 mg) orally 5 times daily, or valaciclovir 20 mg/kg (max 1 g) orally 12-hourly
- Usually 7 days; continue until lesions heal
- Renal impairment: reduce the dose (see product information)
- Return the same day if lesions spread, fever, eye symptoms, poor intake or drowsiness
- Path rejoins step 10Shared downstream outcome
Guideline Source
Traidl S, Heratizadeh A, Werfel T. Algorithms in Allergy: Diagnosis and Treatment of Atopic Dermatitis Complicated by Eczema Herpeticum. Allergy 2025;80(8):2417-2420
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Infants under 3 months and immunocompromised patients need specialist input; neonates under 28 days follow the neonatal HSV guideline
- No trials compare antiviral doses in eczema herpeticum; oral adult doses follow expert algorithm and HSV or zoster dosing
- Antibiotic choice depends on local resistance; MRSA is more common in northern and remote Australia
- Evidence that topical corticosteroids are safe during eczema herpeticum comes from retrospective studies
Contraindicated Populations
Neonates under 28 days (use the neonatal HSV guideline)
Applicable Regions
AUNZEUUS
AU: Child doses follow Perth Children's Hospital ChAMP monographs (aciclovir 2026, valaciclovir 2024) and RCH Melbourne CPGs. Adult IV aciclovir follows the Australian product information.
US: Cefalexin is spelled cephalexin; aciclovir is spelled acyclovir.
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the Eczema Herpeticum (Kaposi Varicelliform Eruption)?
The Eczema Herpeticum (Kaposi Varicelliform Eruption) is a emergency clinical algorithm for Dermatology. It provides a structured decision tree to guide clinical decision-making, based on Traidl S, Heratizadeh A, Werfel T. Algorithms in Allergy: Diagnosis and Treatment of Atopic Dermatitis Complicated by Eczema Herpeticum. Allergy 2025;80(8):2417-2420.
What guideline is the Eczema Herpeticum (Kaposi Varicelliform Eruption) based on?
This algorithm is based on Traidl S, Heratizadeh A, Werfel T. Algorithms in Allergy: Diagnosis and Treatment of Atopic Dermatitis Complicated by Eczema Herpeticum. Allergy 2025;80(8):2417-2420 (DOI: 10.1111/all.16632).
What are the limitations of the Eczema Herpeticum (Kaposi Varicelliform Eruption)?
Known limitations include: Infants under 3 months and immunocompromised patients need specialist input; neonates under 28 days follow the neonatal HSV guideline; No trials compare antiviral doses in eczema herpeticum; oral adult doses follow expert algorithm and HSV or zoster dosing; Antibiotic choice depends on local resistance; MRSA is more common in northern and remote Australia; Evidence that topical corticosteroids are safe during eczema herpeticum comes from retrospective studies. Individual patient factors may require deviation from these recommendations.
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