What is the recommended management for an adult patient presenting with impetigo?

Management of Impetigo in Adults

First-Line Treatment: Topical Antibiotics for Limited Disease

For adults with limited impetigo (up to 100 cm² total area), topical mupirocin 2% ointment applied three times daily for 5-7 days is the recommended first-line treatment. 1, 2

• Mupirocin has demonstrated clinical efficacy equal to oral erythromycin and superior bactericidal activity against Staphylococcus aureus, including antibiotic-resistant strains 3
• Retapamulin 1% ointment is an effective alternative, applied twice daily for 5 days 2, 4
• Retapamulin is FDA-approved for impetigo caused by methicillin-susceptible S. aureus or Streptococcus pyogenes 4
• The treated area may be covered with a sterile bandage or gauze dressing 4

Second-Line Treatment: Oral Antibiotics for Extensive Disease

Oral antibiotics are indicated when impetigo is extensive, topical therapy is impractical, topical treatment has failed, or systemic symptoms are present. 1, 2, 5

For Methicillin-Susceptible S. aureus (MSSA):

• Dicloxacillin or cephalexin (first-generation cephalosporin) are the preferred oral agents 1, 2, 5
• Amoxicillin-clavulanic acid is an acceptable alternative 1
• Avoid penicillin V alone as it lacks adequate coverage against S. aureus 5

For Suspected or Confirmed MRSA:

• Consider empiric MRSA coverage if there is failure to respond to first-line therapy, high local MRSA prevalence, or known risk factors for CA-MRSA 2
• Recommended MRSA-active agents include:
  • Trimethoprim-sulfamethoxazole 1, 2, 5
  • Clindamycin 300-450 mg three times daily 1, 2, 5
  • Doxycycline 1, 2, 5

Treatment Duration and Monitoring

• Complete the full antibiotic course (5-10 days for oral therapy, 5-7 days for topical) even if symptoms improve quickly 2, 5
• Re-evaluate if no improvement occurs after 48-72 hours of appropriate therapy 5
• If treatment failure occurs, obtain cultures and adjust therapy based on susceptibility results 5

Critical Pitfalls to Avoid

• Penicillin alone is inadequate for impetigo due to poor S. aureus coverage 5
• Erythromycin resistance rates are rising; consider local resistance patterns before prescribing 1, 6
• Do not use retapamulin for mucosal surfaces (nasal, oral, ophthalmic, or intravaginal use) 4
• Topical disinfectants are not useful in treating impetigo 6

Evidence Quality Considerations

The Infectious Diseases Society of America 2014 guidelines provide the framework for these recommendations 1, with recent guideline summaries reinforcing topical mupirocin as first-line for limited disease 2. The evidence demonstrates no significant difference in cure rates between topical and oral antibiotics for limited impetigo 1, supporting the preference for topical therapy to minimize systemic antibiotic exposure and resistance development. For extensive disease, oral therapy with anti-staphylococcal coverage remains essential 1, 2, 5.