What is the treatment for impetigo?

Treatment of Impetigo

Topical mupirocin 2% ointment applied three times daily for 5-7 days is the first-line treatment for localized impetigo, while oral antibiotics are recommended for extensive disease. 1, 2

Types and Presentation

• Nonbullous impetigo (70% of cases)

  • Caused by Staphylococcus aureus or Streptococcus pyogenes
  • Presents with honey-colored crusts on erythematous base
  • Typically affects face and extremities

• Bullous impetigo (30% of cases)

  • Caused exclusively by S. aureus
  • Presents with large, flaccid bullae
  • More likely to affect intertriginous areas

Treatment Algorithm

1. Limited/Localized Impetigo

• First-line: Topical antibiotics
  • Mupirocin 2% ointment applied three times daily for 5-7 days 1, 2
    • Clinical efficacy rates of 71-93% demonstrated in clinical studies 2
    • 100% pathogen eradication rate 2
    • Effective against both S. aureus and S. pyogenes 2
  • Alternative topical options: retapamulin or fusidic acid 1

2. Extensive/Multiple Lesions Impetigo

• First-line: Oral antibiotics for 7-10 days 1
  • First-generation cephalosporins (e.g., cephalexin)
  • Clindamycin (300mg three times daily)
  • Amoxicillin/clavulanate

3. Suspected or Confirmed MRSA

• First-line options:
  • Clindamycin (300mg three times daily for 7-10 days) 1
    • Excellent coverage against both MRSA and streptococci
  • Trimethoprim-sulfamethoxazole (160-800mg twice daily for 7-10 days) 1
    • Highly effective against MRSA but has inadequate streptococcal coverage
    • Consider combining with a beta-lactam if streptococcal infection is suspected

4. Penicillin-Allergic Patients

• Clindamycin
• Macrolides (e.g., erythromycin)
• Doxycycline (for patients >8 years old) 1

Special Populations

Children

• Mupirocin has demonstrated 78-96% clinical efficacy in pediatric populations 2
• 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 Response and Follow-up

• Evaluate clinical response within 48-72 hours of starting therapy 1
• Expected resolution within 7-10 days of starting appropriate antibiotics 1
• If no improvement within 3-5 days:
  • Consider obtaining bacterial culture and sensitivity testing
  • Evaluate for alternative diagnosis
  • Consider need for intravenous antibiotics 1

Prevention and Hygiene Practices

• Keep lesions covered when possible
• Use separate towels and linens
• Practice good hand hygiene
• Avoid sharing personal items
• Prompt identification and treatment to prevent spread 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 predisposing to recurrent infection 1
6. Using topical disinfectants (inferior to antibiotics) 3
7. Using mupirocin in infants with moderate or severe renal impairment (risk of polyethylene glycol absorption) 1

Complications

• Poststreptococcal glomerulonephritis is a rare complication (<1 case/1,000 population per year)
• Note that treatment of impetigo has not been shown to prevent this sequela 1

The evidence strongly supports topical mupirocin as equally or more effective than oral antibiotics for localized impetigo, with fewer side effects 1, 2, 4. For extensive disease, oral antibiotics remain the standard of care, with selection guided by local resistance patterns and suspected pathogens.