Eczema Herpeticum: When a Herpes Infection Complicates Eczema

What Is Eczema Herpeticum?

Eczema herpeticum is what happens when the herpes simplex virus (the same virus that causes cold sores) infects skin that has already been damaged and weakened by eczema (atopic dermatitis). In people with healthy, intact skin, a herpes infection stays localized—causing a cold sore on the lip or a small cluster of blisters. But eczematous skin has a damaged barrier and a weakened local immune defense, allowing herpes to spread widely and rapidly across every area of inflamed skin on the body.

The result is a sudden outbreak of clustered blisters across multiple body areas—often the face, neck, and arms—combined with fever and feeling very unwell. This is a medical emergency that requires immediate antiviral treatment.

Eczema herpeticum affects roughly 2–3% of people with atopic dermatitis during their lifetime (higher in those with severe eczema). It occurs most commonly in infants and young children under age 2, though it can happen at any age in someone with eczema or another condition that breaks down the skin barrier.

Signs and Symptoms

The warning signs of eczema herpeticum often appear suddenly:

• Widespread blisters: Clusters of small (1–3 mm) blisters appearing simultaneously across multiple areas of eczema-affected skin—not just in one spot as a typical cold sore would. The face, neck, arms, and torso are most commonly affected.
• Rapid progression: Blisters quickly turn into pustules (pus-filled), then crust over within 7–10 days
• Punched-out erosions: The crusted lesions often leave behind small, well-defined open sores with a characteristic "punched-out" appearance
• Severe itching
• Fever: Usually 38–39°C (100–102°F)
• Feeling very unwell: Fatigue, malaise, headache, swollen lymph nodes

Secondary bacterial infection develops in 25–50% of cases, causing increased pus, redness spreading beyond individual lesions (cellulitis), and potentially signs of blood infection (sepsis) if untreated.

Danger signs requiring emergency care: Eye pain or redness (herpes keratitis—HSV can scar the cornea), altered mental status, severe illness in an infant.

What Causes Eczema Herpeticum?

Two things must happen for eczema herpeticum to develop:

1. Existing eczema or another skin barrier condition: Eczematous skin produces fewer antimicrobial peptides (natural virus-fighting proteins) and has a Th2-skewed immune response that impairs antiviral defenses. This means when herpes virus contacts eczema-affected skin, local immune protection is too weak to contain it.
2. Exposure to HSV: Most commonly through direct contact with someone who has a cold sore. Parents and caregivers with oral herpes (even without visible sores, since asymptomatic viral shedding occurs regularly) can inadvertently transmit HSV to infants with eczema through kissing or skin contact.

Once established in broken skin, HSV spreads by moving directly from cell to cell—this is why blisters appear simultaneously across all areas of damaged skin rather than starting in one spot and slowly radiating outward.

Treatment Options

Eczema herpeticum requires urgent treatment—do not wait to see if it resolves on its own.

• Systemic antiviral medication: Acyclovir is the first-line treatment. Mild-to-moderate cases are treated with oral acyclovir (or valacyclovir) for 7–10 days. Severe cases—especially in infants, immunocompromised patients, or anyone with eye or neurological involvement—require intravenous (IV) acyclovir in a hospital. Treatment reduces the duration and severity of the outbreak and prevents life-threatening complications.
• Hospitalization: Required for infants, anyone with severe disease, signs of secondary bacterial infection, eye involvement, or neurological symptoms.
• Antibiotics: Added if secondary bacterial skin infection develops (occurs in 25–50% of cases).
• Eczema management: Continue (or modify) eczema treatment as directed by your dermatologist. Topical corticosteroids are typically paused on the actively infected areas during the acute outbreak but resumed once the infection is cleared—stopping eczema treatment entirely can worsen the eczema flare that follows.
• Eye evaluation: If there is any eye pain, redness, or sensitivity to light, an urgent ophthalmology evaluation is needed to rule out herpes keratitis.

Prevention

• Anyone with active cold sores should avoid close face contact (kissing, nuzzling) with infants or children who have eczema
• Keep eczema well-controlled—intact, less-inflamed skin is more resistant to viral spread
• Suppressive antiviral therapy (daily low-dose acyclovir or valacyclovir) may be prescribed for people with frequent recurrences of eczema herpeticum

When to See a Dermatologist

• A person with eczema develops sudden widespread blisters, especially with fever—same-day evaluation is needed
• Your eczema is suddenly much worse and looks different from your usual flares—blisters are a red flag
• There is any eye involvement (pain, redness, vision changes) alongside a skin outbreak
• An infant or young child with eczema develops a fever alongside new skin blistering
• You have recurrent episodes of eczema herpeticum and want to discuss preventive antiviral therapy

Frequently Asked Questions

Is eczema herpeticum contagious to others?

The herpes virus that causes eczema herpeticum is the same HSV that causes cold sores, so it can be transmitted to others through direct contact with active blisters or viral shedding. However, in a person with a normal skin barrier, exposure typically causes only a localized cold sore—not widespread disease. Eczema herpeticum itself (the extensive spread) only happens in people with damaged skin barriers.

Can eczema herpeticum recur?

Yes. Once someone has had eczema herpeticum, the herpes virus remains dormant in nerve cells and can reactivate, causing another episode. Recurrences tend to be less severe than the first episode because some immunity develops. For people with frequent recurrences, daily suppressive antiviral therapy significantly reduces the number of episodes.

How do I tell eczema herpeticum apart from a bad eczema flare?

Key differences: eczema herpeticum involves true blisters (fluid-filled vesicles and pustules), fever, and feeling systemically unwell—these do not occur with a standard eczema flare. The blisters also appear suddenly across multiple body areas at once, while eczema flares tend to worsen gradually. When in doubt, see a dermatologist or go to urgent care the same day.

My infant has eczema. Should I be worried about cold sores?

Yes—this is an important concern. Adults and older children with oral herpes (cold sores) can transmit HSV to infants with eczema, sometimes without having a visible sore at the time (due to asymptomatic shedding). Anyone with a history of cold sores should avoid kissing infants, especially around the face, and should wash hands carefully. Keeping eczema well-controlled is also protective.

Trusted Resources

• American Academy of Dermatology: Atopic Dermatitis
• National Eczema Association
• Mayo Clinic: Atopic Dermatitis

Always consult a board-certified dermatologist for diagnosis and personalized treatment recommendations.