What is the treatment for impetigo?

Treatment of Impetigo

For impetigo, first-line treatment is topical mupirocin or retapamulin for limited disease (less than 100 cm²), while oral clindamycin is recommended for extensive disease or when topical therapy is impractical. 1

Clinical Presentation and Diagnosis

Impetigo presents in two main forms:

• Nonbullous impetigo (70% of cases): Caused by Staphylococcus aureus or Streptococcus pyogenes; characterized by honey-colored crusts on erythematous base, typically affecting face and extremities 1, 2
• Bullous impetigo (30% of cases): Caused exclusively by S. aureus; presents with large, flaccid bullae, more likely to affect intertriginous areas 1, 2

Diagnosis is primarily clinical based on the characteristic appearance of lesions.

Treatment Algorithm

1. Limited Disease (< 100 cm²)

• First-line: Topical antibiotics 1, 3
  • Mupirocin 2% ointment applied three times daily for 5-7 days
    • Clinical efficacy rates of 71-93% 3
    • Pathogen eradication rates of 94-100% 3
  • Retapamulin as an alternative topical option 1

2. Extensive Disease (> 100 cm²) or Impractical Topical Application

• First-line oral therapy: 1
  • Clindamycin 300mg three times daily for 7-10 days
    • Excellent coverage against both MRSA and streptococci
  • First-generation cephalosporins (e.g., cephalexin)
  • Penicillinase-resistant semisynthetic penicillins

3. For Suspected/Confirmed MRSA

• Oral options: 1
  • Clindamycin 300mg three times daily for 7-10 days
  • Trimethoprim-sulfamethoxazole 160-800mg twice daily for 7-10 days
    • Note: Has inadequate streptococcal coverage; may need to combine with a beta-lactam if streptococcal infection is suspected

4. Alternative Oral Options

• Doxycycline 100mg twice daily for 7-10 days (for patients >8 years) 1
• Linezolid 600mg twice daily for 7-10 days (superior clinical and microbiological cure rates for MRSA skin infections) 1

Special Considerations

Pediatric Patients

• Mupirocin has shown 78-96% clinical efficacy in pediatric populations 3
• Avoid tetracyclines (doxycycline, minocycline) in children under 8 years due to risk of inhibiting bone growth 1
• For hospitalized children with complicated infections, vancomycin is first choice, followed by clindamycin and linezolid 1

Treatment Duration and Monitoring

• Typical duration: 5-7 days for topical therapy, 7-10 days for oral therapy 1
• Evaluate clinical response within 48-72 hours of starting therapy 1
• If no improvement within 3-5 days, consider:
  • Obtaining bacterial culture and sensitivity testing
  • Alternative diagnosis
  • Possible need for intravenous antibiotics 1

Prevention of Transmission

• Keep lesions covered when possible
• Use separate towels and linens
• Practice good hand hygiene
• Systemic therapy is preferred for outbreaks affecting several people to help decrease transmission 1

Common Pitfalls to Avoid

1. Failing to consider MRSA in recalcitrant cases
2. Using penicillin alone (inferior to other antibiotics for impetigo)
3. Inadequate duration of therapy
4. Relying solely on topical therapy for extensive disease
5. Not addressing underlying conditions that predispose to recurrent infection 1
6. Using topical disinfectants (inferior to antibiotics) 2, 4

Complications

• Poststreptococcal glomerulonephritis is rare (<1 case/1,000 population per year)
• Note that treatment does not prevent this complication 1