AKT · Dermatology/Dermatological emergencies

Eczema herpeticum

Disseminated HSV infection of eczematous skin

Overview

A dermatological EMERGENCY: widespread herpes simplex virus infection superimposed on eczema (or another barrier-defective dermatosis). A rapidly spreading eruption of MONOMORPHIC punched-out erosions in an unwell, febrile patient — needs prompt systemic aciclovir, and ophthalmology if near the eyes.

Recognise

Rapidly worsening eczema with clusters of MONOMORPHIC (all the same stage), punched-out, "dingbat", 1–3 mm erosions/vesicles that may coalesce
Systemic upset — fever, malaise, lymphadenopathy; pain (eczema is usually itchy, eczema herpeticum is painful)
Often in a child/young adult with known atopic eczema; can be recurrent

Red flags

Systemic illness, rapid spread, periocular involvement (risk to sight) → same-day admission, IV aciclovir, ophthalmology; secondary bacterial infection

Differentials & how to tell them apart

Infected (bacterial) eczemaweeping golden crust (Staph), not monomorphic punched-out vesicles — but they can coexist

Primary varicella (chickenpox)lesions of DIFFERENT stages (vs the monomorphic single-stage lesions of eczema herpeticum), centripetal

Hand-foot-mouth / other viral exanthemdistribution and morphology differ

Acute flare of eczemaitchy not painful, no monomorphic punched-out erosions or systemic upset

Clinical image

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Eczema herpeticum — clinical imagesDermNet

Investigations

Clinical — do not delay treatment. Viral swab (HSV PCR) and bacterial swab to confirm/assess superinfection. Assess hydration and eye involvement.

Management

Prompt systemic aciclovir (IV if severe/periocular) + ophthalmology if near the eyes

1Treat urgently with systemic aciclovir (oral if mild and well; IV if extensive, systemically unwell, or periocular). Admit the unwell/young patient.Gate: Monomorphic punched-out erosions on eczema in an UNWELL patient = eczema herpeticum (HSV), NOT just infected eczema → it needs systemic ACICLOVIR (not just antibiotics), and periocular involvement is a same-day ophthalmology emergency
2Add antibiotics for bacterial superinfection; ophthalmology for any eye involvement; restart eczema control once settled. Recurrent episodes may need antiviral prophylaxis.

Systemic aciclovir (oral, or IV if severe/systemically unwell or periocular) — the priority — start promptly

Antibiotics if secondarily infected (flucloxacillin) — Staph superinfection is common

Ophthalmology + topical/systemic antivirals if periocular — sight-threatening

Key points

The discriminator from an ordinary eczema flare: it is PAINFUL, monomorphic, punched-out, and the patient is unwell. Aciclovir is the answer, not just antibiotics. Eyes near lesions = emergency.

Monitor & prognosis

Systemic response to aciclovir, hydration, eye, secondary infection.

Good with prompt antiviral treatment; dangerous if missed (esp. ocular/dissemination).

Source: NICE CKS Eczema - atopic (eczema herpeticum); DermNet