What is the recommended management for impetigo?

Management of Impetigo

For limited impetigo, use topical mupirocin 2% ointment three times daily for 5-7 days; for extensive disease involving multiple sites, use oral antibiotics for 7 days targeting both S. aureus and streptococci. 1, 2

First-Line Treatment: Topical Antibiotics for Limited Disease

• Mupirocin 2% ointment applied three times daily for 5-7 days is the first-line treatment for localized impetigo (FDA-approved for S. aureus and S. pyogenes). 1, 2
• Retapamulin 1% ointment applied twice daily for 5 days is an effective alternative for limited disease in patients aged 9 months or older (FDA-approved for methicillin-susceptible S. aureus only). 1, 3
• Topical antibiotics are superior to placebo and demonstrate better efficacy than some oral antibiotics like erythromycin. 4

When to Use Oral Antibiotics

Oral antibiotics are indicated when:

• Impetigo involves multiple sites or extensive body surface area 1
• Topical therapy is impractical (e.g., scalp involvement, numerous lesions) 5
• Topical treatment has failed after 48-72 hours 1
• Systemic symptoms are present 6

Oral Antibiotic Regimens

For Methicillin-Susceptible S. aureus (MSSA):

• Dicloxacillin 250 mg four times daily for adults (weight-adjusted for children) 1
• Cephalexin 250-500 mg four times daily for adults (weight-adjusted for children) 1
• Treatment duration: 7 days 1

For Suspected or Confirmed MRSA:

• Clindamycin 300-450 mg three times daily for adults 1
• Trimethoprim-sulfamethoxazole (note: inadequate for streptococcal coverage alone) 7
• Doxycycline (contraindicated in children under 8 years) 1

Critical Pitfalls to Avoid

• Never use penicillin alone—it lacks adequate S. aureus coverage and is seldom effective. 1, 7
• Topical disinfectants are inferior to antibiotics and should not be used. 1, 8
• Erythromycin resistance rates are rising; avoid as first-line therapy. 7

When to Consider MRSA Coverage

Empiric MRSA therapy should be considered in:

• Patients residing in long-term care facilities 1
• Failure to respond to first-line therapy after 48-72 hours 1
• High local prevalence of community-acquired MRSA 6

Pediatric-Specific Considerations

• All oral antibiotic dosing must be weight-adjusted for children. 1
• Tetracyclines (doxycycline, minocycline) are contraindicated in children under 8 years. 1, 5
• Retapamulin is approved for patients 9 months and older. 3

Treatment Monitoring and Follow-Up

• Re-evaluate if no improvement occurs after 48-72 hours of therapy. 1
• Obtain cultures if treatment fails, MRSA is suspected, or recurrent infections occur. 5
• Keep lesions covered with clean, dry bandages to prevent spread. 1
• Complete the full antibiotic course even if symptoms improve quickly to prevent complications like post-streptococcal glomerulonephritis. 6

Treatment Algorithm Summary

Limited disease (few lesions, localized):

• Start with topical mupirocin 2% three times daily for 5-7 days 1, 2
• Alternative: retapamulin 1% twice daily for 5 days 1, 3

Extensive disease (multiple sites, impractical topical therapy):

• Use oral antibiotics for 7 days: dicloxacillin or cephalexin for MSSA 1
• If MRSA suspected: clindamycin, TMP-SMX, or doxycycline (age-appropriate) 1, 7

Treatment failure at 48-72 hours:

• Obtain cultures and adjust therapy based on susceptibility 5
• Consider MRSA coverage if not already initiated 1