What is the treatment for Impetigo?

Treatment of Impetigo

For impetigo treatment, topical mupirocin 2% ointment applied three times daily for 7-10 days is the first-line therapy for limited disease, while oral antibiotics such as cephalexin or clindamycin for 7 days are recommended for extensive disease. 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 an erythematous base
  • Typically affects the 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

Treatment Algorithm

1. Limited Disease (Few Lesions)

• First-line: Topical mupirocin 2% ointment applied three times daily for 7-10 days 1, 3

  • Clinical efficacy rates of 71-93% in clinical trials 3
  • Effective against both S. aureus and S. pyogenes 3

• Alternatives: Retapamulin or fusidic acid (where available) 1, 2

2. Extensive Disease (Multiple Lesions or Large Areas)

• First-line oral options:

  • For MSSA: Dicloxacillin or cephalexin for 7 days 1
  • For confirmed streptococcal infection: Oral penicillin for 7 days 1
  • For suspected MRSA: Clindamycin 300mg three times daily for 7-10 days 1

• Important note: Trimethoprim-sulfamethoxazole (TMP-SMX) has inadequate streptococcal coverage and should not be used as monotherapy unless MRSA is confirmed and streptococcal infection is ruled out 1, 2

Evidence-Based Insights

Topical mupirocin has been shown to be as effective as or superior to oral antibiotics in multiple studies:

• In FDA clinical trials, mupirocin demonstrated 93% efficacy compared to 78.5% for oral erythromycin 3
• Mupirocin showed 100% pathogen eradication in evaluable patients 3
• A Cochrane review found topical mupirocin was slightly superior to oral erythromycin (RR 1.07,95% CI 1.01 to 1.13) 4

Oral antibiotic comparisons show:

• Penicillin is inferior to erythromycin and cloxacillin 4
• Clindamycin provides excellent coverage against both MRSA and streptococci 1

Special Considerations

• Treatment duration: Standard duration is 7 days for oral antibiotics; clinical response should be evaluated within 48-72 hours 1
• Expected resolution: Within 7-10 days of starting appropriate treatment 1
• Pediatric considerations: Avoid tetracyclines (doxycycline, minocycline) in children under 8 years due to risk of inhibiting bone growth 1
• Treatment failure: If no improvement within 3-5 days, consider bacterial culture and sensitivity testing, alternative diagnosis, or possible need for intravenous antibiotics 1

Common Pitfalls to Avoid

1. Failure to consider MRSA in recalcitrant impetigo 1
2. Using penicillin as monotherapy, which has been shown to be inferior to other antibiotics 1, 4
3. Inadequate duration of therapy leading to treatment failure 1
4. Relying solely on topical therapy for extensive disease 1
5. Using topical disinfectants, which are inferior to antibiotics and should not be used 2, 4
6. Using TMP-SMX alone when streptococcal infection has not been ruled out 1, 2

Prevention Strategies

• Keep lesions covered when possible
• Use separate towels and linens
• Practice good hand hygiene
• Prompt identification and treatment of cases 1

Antimicrobial Resistance Concerns

Increasing worldwide antimicrobial resistance to existing topical agents is a growing concern 5. Consider local resistance patterns when selecting empiric therapy, especially in areas with high MRSA prevalence.