Management of Eczema Flare During Hand-Foot-Mouth Disease
Continue standard eczema treatment with emollients and appropriate-potency topical corticosteroids while managing the concurrent hand-foot-mouth disease supportively, but critically distinguish this from eczema herpeticum which requires immediate antiviral therapy.
Key Clinical Distinction: Rule Out Eczema Herpeticum First
The most critical initial step is differentiating hand-foot-mouth disease (HFMD) from eczema herpeticum, as the latter is a medical emergency requiring immediate acyclovir 1. Look for:
- Eczema herpeticum: Grouped, punched-out erosions or vesiculation; requires oral acyclovir early, or IV if patient is febrile/ill 1
- HFMD/Eczema coxsackium: Vesiculobullous eruptions that preferentially affect areas of active or previously affected eczematous skin 2, 3
Common pitfall: Eczema coxsackium can mimic eczema herpeticum clinically, with widespread vesicular eruptions on eczematous skin 3, 4. When in doubt, send viral swabs for both herpes simplex and enterovirus PCR 5.
Understanding "Eczema Coxsackium"
This is an atypical presentation of HFMD that occurs in 55% of children with atopic dermatitis during coxsackievirus A6 outbreaks 3. Key features include:
- Vesiculobullous and erosive eruptions accentuated in areas of eczematous dermatitis 3
- Distribution beyond classic HFMD sites (palms, soles, buttocks) to include perioral area, extremities, trunk, and pressure areas 3, 5
- Can involve >10% body surface area in 61% of cases 3
- May present without typical oral lesions 2
Treatment Algorithm
1. Maintain Baseline Eczema Management
Continue the patient's established eczema regimen [1-1]:
- Emollients: Apply after bathing to provide surface lipid film and prevent water loss 1
- Topical corticosteroids: Use the least potent preparation needed to control the eczema, applied no more than twice daily 1
- Avoid very potent or potent steroids for extended periods 1
2. Address Secondary Bacterial Infection if Present
Look for crusting or weeping suggesting bacterial superinfection 1:
- First-line: Flucloxacillin for Staphylococcus aureus (most common pathogen) 1
- Alternative: Erythromycin if penicillin allergy or flucloxacillin resistance 1
- Send bacterial swabs if not responding to treatment 1
3. Supportive Care for HFMD
The viral infection itself requires only supportive management 4:
- Symptomatic relief for fever and discomfort
- Maintain hydration
- No antiviral therapy needed (unlike eczema herpeticum)
- Infection control precautions to prevent spread
4. Avoid Inappropriate Treatments
Do not give acyclovir unless herpes simplex is confirmed 3, 5. The CVA6-associated outbreak led to many cases being misdiagnosed as eczema herpeticum, resulting in unnecessary hospitalization and inappropriate treatment 3.
Expected Course and Complications
- Symptoms typically resolve in 10 days (mean) 6
- Delayed complications to counsel families about:
When to Escalate Care
Refer to specialist or consider admission if 1:
- Failure to respond to first-line eczema management
- Diagnostic uncertainty between eczema coxsackium and eczema herpeticum
- Systemic symptoms suggesting complications (though rare with HFMD) 3
- Severe, widespread involvement requiring intensive management
Evidence Strength Note
While the general eczema management guidelines are well-established [1-1], the specific entity of eczema coxsackium is described primarily in case series and retrospective studies from the 2011-2012 CVA6 outbreak 2, 3, 6. The key clinical principle remains: maintain standard eczema care while providing supportive management for the concurrent viral infection, with vigilance for bacterial superinfection.