What is the treatment for bullous impetigo?

Treatment of Bullous Impetigo

Bullous impetigo should be treated with either topical mupirocin or retapamulin applied twice daily for 5 days as first-line therapy, with oral antibiotics reserved for extensive disease or outbreaks affecting multiple people. 1

Causative Organism and Diagnosis

• Bullous impetigo is caused exclusively by Staphylococcus aureus strains that produce toxins cleaving the dermal-epidermal junction, forming fragile, thin-roofed vesicopustules 1, 2
• These lesions may rupture, creating crusted, erythematous erosions often surrounded by remnants of the blister roof 1
• Diagnosis is typically made clinically based on the characteristic appearance, though Gram stain and culture of pus or exudates can help identify the causative organism 1
• In typical cases, treatment without culture is reasonable 1

Treatment Options

Topical Therapy (First-Line)

• Topical mupirocin or retapamulin applied twice daily for 5 days is the recommended first-line treatment for limited bullous impetigo 1
• Mupirocin has demonstrated 71% clinical efficacy compared to 35% for placebo in clinical trials 3
• Topical therapy is indicated for patients with limited disease and few lesions 1, 4

Oral Antibiotic Therapy

• Oral antibiotics are recommended for:

  • Patients with numerous lesions 1
  • Outbreaks affecting several people (to decrease transmission) 1
  • Cases where topical therapy is impractical 4

• Recommended oral regimen is a 7-day course with an agent active against S. aureus 1

• For methicillin-susceptible S. aureus (most cases):

  • Dicloxacillin or cephalexin are recommended 1, 5
  • Cephalexin can be given twice daily with equal efficacy to four-times-daily regimens, potentially improving compliance 5

• For suspected or confirmed MRSA:

  • Doxycycline, clindamycin, or sulfamethoxazole-trimethoprim (SMX-TMP) are recommended 1, 4
  • Note that SMX-TMP covers MRSA but is inadequate for streptococcal infections 4

• Penicillin alone is not effective for bullous impetigo 4, 5

Special Considerations

• Monitor for clinical response within 24-48 hours when using oral antibiotics 1

• If progression occurs despite antibiotics, consider:

  • Infection with resistant organisms 1
  • Presence of a deeper, more serious infection than initially recognized 1

• For patients with severe infection or progression despite empirical therapy:

  • Consider agents effective against MRSA (vancomycin, linezolid, or daptomycin) 1
  • Base treatment on appropriate Gram stain, culture, and susceptibility results 1

• Be aware of increasing antibiotic resistance:

  • Rising rates of MRSA in community settings 1, 4
  • Documented mupirocin-resistant strains 4

Prognosis and Complications

• Bullous impetigo typically resolves within 2-3 weeks without scarring 4, 2
• Complications are rare, with poststreptococcal glomerulonephritis being the most serious (though uncommon with bullous impetigo caused exclusively by S. aureus) 4, 2

Treatment Algorithm

1. For limited disease (few lesions):

   • Topical mupirocin or retapamulin twice daily for 5 days 1

2. For extensive disease (numerous lesions) or outbreaks:

   • Oral antibiotics for 7 days 1
   • For MSSA: dicloxacillin or cephalexin 1
   • For suspected/confirmed MRSA: doxycycline, clindamycin, or SMX-TMP 1

3. For treatment failure or severe disease:

   • Obtain cultures and susceptibility testing 1
   • Consider MRSA-active agents based on local resistance patterns 1, 4