How to manage a patient with refractory atopic (atopic dermatitis) eczema and a secondary Methicillin-resistant Staphylococcus aureus (MRSA) infection?

Management of Refractory Atopic Eczema with Secondary MRSA Infection

For refractory atopic dermatitis with secondary MRSA infection, immediately initiate systemic anti-MRSA antibiotics while continuing topical corticosteroids, then implement aggressive decolonization protocols including dilute bleach baths (0.005% sodium hypochlorite) twice weekly and intranasal mupirocin. 1, 2

Immediate Treatment of Active MRSA Infection

Systemic Antibiotic Selection

• Start with oral antibiotics effective against MRSA since flucloxacillin (first-line for methicillin-sensitive S. aureus) will not work 1, 3
• Use trimethoprim-sulfamethoxazole or clindamycin as first-line oral agents for community-acquired MRSA 2
• If resistance to both clindamycin and trimethoprim-sulfamethoxazole develops (which can occur in atopic dermatitis patients), linezolid may be required 2
• Erythromycin can be used in penicillin-allergic patients, though resistance patterns must be considered 1, 3

Critical Point About Topical Corticosteroids During Infection

• Do not discontinue topical corticosteroids when treating bacterial infection - they remain the primary treatment for the underlying eczema when appropriate systemic antibiotics are given concurrently 3
• This is a common pitfall: providers often withhold anti-inflammatory therapy during infection, but guidelines explicitly state to continue it 3

Aggressive Decolonization Protocol

Bleach Bath Regimen

• Implement dilute bleach baths (0.005% sodium hypochlorite) twice weekly - this has strong evidence (Level A, BII) for patients prone to skin infections 1
• Continue bleach baths even after acute infection resolves to prevent recurrence 4

Intranasal Mupirocin

• Apply intranasal mupirocin in conjunction with bleach baths (Level AI recommendation) 1
• This combination is particularly important as one case series demonstrated that aggressive decolonization including intranasal mupirocin and bleach baths successfully converted multiresistant MRSA colonization back to methicillin-susceptible S. aureus 2

Environmental Decontamination

• Cleanse household items and surfaces with dilute bleach to prevent recolonization 2, 4
• Minimize contamination risk of topical agents by using proper hygiene when applying medications 4

Optimizing Underlying Atopic Dermatitis Control

Topical Anti-Inflammatory Therapy

• Use potent topical corticosteroids (TCS) as first-line therapy for refractory disease (Level A, AI recommendation) 1
• Apply no more than twice daily to affected areas 3
• Implement short "steroid holidays" when possible to minimize side effects, particularly pituitary-adrenal suppression 1, 3
• Exercise caution with very potent corticosteroids in thin-skinned areas (face, neck, flexures, genitals) where atrophy risk is higher 3

Topical Calcineurin Inhibitors (TCI)

• Add tacrolimus or pimecrolimus as steroid-sparing agents - these are effective in acute and maintenance therapy (Level A, AI recommendation) 1, 5
• TCIs can be used in conjunction with topical corticosteroids as first-line treatment 5
• Consider preceding TCS use to lessen severity of cutaneous reactions from TCIs (Level BII) 1

Essential Adjunctive Measures

• Liberal application of emollients is cornerstone therapy - apply regularly even when eczema appears controlled 3, 5
• Apply emollients after bathing to provide surface lipid film that retards water loss 3
• Use soap-free cleansers and avoid alcohol-containing products 3

Second-Line Options for Refractory Disease

Wet Wrap Therapy

• Consider wet wrap therapy in conjunction with TCS for particularly erythematous and pruritic refractory cases (Level A, BII recommendation) 1, 4
• This helps "cool down" acute flares 4

Phototherapy

• Narrow-band UVB (312 nm) is recommended for recalcitrant disease after failure of first-line topical agents (Level A, BII recommendation) 1, 3
• This is safe and effective for moderate to severe atopic dermatitis 5
• Some concern exists about long-term adverse effects including premature skin aging and cutaneous malignancies, particularly with PUVA 1, 3

Systemic Immunosuppressants

• Consider cyclosporine, azathioprine, or methotrexate for severe disease refractory to topical treatments and phototherapy 1
• These should be considered before mycophenolate mofetil (MMF) and interferon-gamma 1

Critical Pitfalls to Avoid

Systemic Corticosteroids

• Generally avoid systemic corticosteroids given unfavorable risk/benefit ratio 1
• Short courses can lead to atopic flares after discontinuation 1
• Only use in acute severe exacerbations as bridge therapy to other systemic treatments (Level BII) 1
• Never use for maintenance treatment - the decision should only be made after exhausting all other options 1, 3
• Risk of pituitary-adrenal suppression is significant, particularly in children where growth interference can occur 1

Antihistamine Misuse

• Do not prescribe non-sedating antihistamines - they have little to no value in atopic eczema (Level AII recommendation against use) 1, 3
• Sedating antihistamines may help with nighttime pruritus through sedative properties only, used short-term during severe flares 1, 3

Steroid Phobia

• Address patient/parent fears about topical corticosteroids - undertreatment due to "steroid phobia" is common and leads to poor outcomes 1
• Explain different potencies and appropriate use clearly 3

When to Escalate or Refer

• Failure to respond to moderate potency topical corticosteroids after 4 weeks 3
• Development of multiresistant MRSA requiring linezolid or other advanced antibiotics 2
• Need for systemic immunosuppressive therapy or phototherapy 3
• Suspected eczema herpeticum (grouped vesicles, punched-out erosions, sudden deterioration with fever) - this is a medical emergency requiring immediate IV acyclovir 3, 6

Monitoring and Follow-Up

• Watch for signs of persistent or worsening infection: increased crusting, weeping, pustules 3
• Monitor for development of antibiotic resistance - the incidence of multi-drug resistant MRSA is higher in AD patients compared to healthy populations 7
• Assess adherence to decolonization protocols - education is crucial for success 4
• Continue maintenance therapy indefinitely with emollients and appropriate anti-inflammatory agents even after infection clears 3, 5