What is the treatment for impetigo?

Treatment of Impetigo

Impetigo should be treated with topical antibiotics as first-line therapy, specifically mupirocin or retapamulin, for localized infections with oral antibiotics reserved for extensive disease. 1, 2, 3

Clinical Presentation and Etiology

• Impetigo is a highly contagious bacterial skin infection affecting the superficial layers of the epidermis, predominantly in children 2-5 years of age 1, 4
• Two main types exist:
  • Nonbullous impetigo (70% of cases): characterized by honey-colored crusts on exposed areas like the face and extremities 4
  • Bullous impetigo (30% of cases): presents with flaccid bullae, more common in intertriginous areas 4
• Causative organisms:
  • Nonbullous: Staphylococcus aureus and/or Streptococcus pyogenes 1
  • Bullous: Exclusively S. aureus 4

Treatment Algorithm

First-Line Treatment: Topical Antibiotics

• For limited lesions:

  • Mupirocin 2% ointment applied to affected areas three times daily for 5-7 days 1, 2
  • Retapamulin 1% ointment applied twice daily for 5 days 3, 5
  • Fusidic acid (where available) is an alternative with similar efficacy to mupirocin 5, 6

• Advantages of topical therapy:

  • Equal or superior efficacy to oral antibiotics for limited disease 5, 7
  • Fewer systemic side effects compared to oral antibiotics 5, 7
  • Targeted delivery to infection site 4

Second-Line Treatment: Oral Antibiotics

• Indications for oral antibiotics:

  • Extensive disease (multiple lesions) 1, 4
  • When topical therapy is impractical 7
  • Failure of topical treatment 1
  • Systemic symptoms present 1

• Recommended oral antibiotics:

  • Dicloxacillin or first-generation cephalosporins (e.g., cephalexin) 1
  • Clindamycin for suspected MRSA infections 4
  • Macrolides (e.g., erythromycin) or amoxicillin/clavulanate as alternatives 4, 7

• Important note: Oral penicillin V is not recommended as it is seldom effective against S. aureus 7

Special Considerations

Community-Acquired MRSA (CA-MRSA)

• Consider empiric therapy for CA-MRSA in the following situations:

  • Patients at risk for CA-MRSA infection 1
  • Failure to respond to first-line therapy 1
  • High local prevalence of CA-MRSA 1, 4

• Treatment options for suspected CA-MRSA:

  • Topical: Mupirocin (if susceptible) 4
  • Oral: Trimethoprim-sulfamethoxazole, clindamycin, or doxycycline 1, 4

Treatment Pitfalls to Avoid

• Avoid topical disinfectants: They are inferior to antibiotics and should not be used 5, 7
• Monitor for resistance: Growing resistance rates to commonly used antibiotics, including mupirocin, have been reported 1, 4
• Avoid penicillin monotherapy: Penicillin is inferior to other antibiotics for impetigo treatment 5, 7
• Re-evaluate non-responders: If no improvement after 24-48 hours, consider resistance or deeper infection 1

Treatment Duration and Follow-up

• Most cases resolve within 7 days of appropriate treatment 4, 7
• Complete the full course of prescribed antibiotics even if symptoms improve quickly 1, 4
• Impetigo typically heals without scarring within 2-3 weeks 4
• Complications are rare but can include post-streptococcal glomerulonephritis (though treatment may not prevent this sequela) 1, 4