What is the treatment for Impetigo contagiosa?

Treatment of Impetigo Contagiosa

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

Treatment Algorithm Based on Disease Extent

Limited/Localized Disease (First-Line)

• Topical mupirocin 2% ointment applied three times daily for 5 days is the recommended first-line treatment 1, 2, 3
• Retapamulin 1% ointment applied twice daily for 5 days is an alternative topical option 2
• Topical antibiotics demonstrate superior cure rates compared to placebo (RR 2.24,95% CI 1.61-3.13) and are as effective as oral erythromycin 4
• FDA-approved mupirocin shows 71% clinical efficacy in impetigo versus 35% for placebo, with 94% pathogen eradication rates 3

Extensive Disease (Multiple Sites or Impractical Topical Therapy)

• Oral antibiotics for 7 days are recommended when topical therapy is impractical or disease involves multiple sites 1, 2

For Methicillin-Susceptible S. aureus (MSSA):

• Dicloxacillin 250 mg four times daily (adults) 2
• Cephalexin 250-500 mg four times daily (adults) 1, 2

For Methicillin-Resistant S. aureus (MRSA) or suspected MRSA:

• Clindamycin 300-450 mg three times daily (adults) 1, 2
• Doxycycline (not for children under 8 years) 1, 2
• Trimethoprim-sulfamethoxazole (SMX-TMP) 1

Critical Pitfalls to Avoid

• Penicillin alone is NOT effective for impetigo as it lacks adequate coverage against S. aureus 2, 4
• Topical disinfectants are inferior to antibiotics and should not be used 2, 4
• Oral erythromycin is inferior to topical mupirocin (pooled RR 1.07,95% CI 1.01-1.13) and faces increasing resistance rates 4

When to Consider MRSA Coverage

• Empiric therapy for community-acquired MRSA should be initiated in patients who fail first-line therapy or have risk factors including residence in long-stay care facilities, recent hospitalization within 30 days, or recent antibiotic exposure 5, 2

Treatment Monitoring and Infection Control

• Re-evaluate if no improvement occurs after 48-72 hours of therapy 1, 2
• Keep lesions covered with clean, dry bandages 1, 2
• Maintain good personal hygiene to prevent spread 1, 2
• For outbreaks affecting multiple people, oral therapy is recommended to decrease transmission 1

Pediatric Considerations

• Oral antibiotic dosing must be weight-adjusted for children 2
• Tetracyclines (doxycycline, minocycline) are contraindicated in children under 8 years of age 2
• Mupirocin demonstrates 78% clinical efficacy in pediatric patients aged 2 months to 15 years versus 36% for placebo 3

Causative Organisms

• Nonbullous impetigo (70% of cases) is caused by S. aureus and/or Streptococcus pyogenes 1, 6
• Bullous impetigo (30% of cases) is caused exclusively by S. aureus 1, 6
• Gram stain and culture are recommended to identify causative organisms, though treatment without these studies is reasonable in typical cases 1