What is the recommended treatment for impetigo?

Treatment of Impetigo

For impetigo, topical mupirocin or retapamulin applied twice daily for 5 days is the recommended first-line treatment for limited disease, while oral antibiotics are recommended for extensive disease or during outbreaks affecting multiple individuals. 1

Diagnosis and Classification

Impetigo presents in two main forms:

• Nonbullous impetigo (70% of cases): Characterized by honey-colored crusts on face and extremities, caused by Staphylococcus aureus or Streptococcus pyogenes 2
• Bullous impetigo (30% of cases): Characterized by large, flaccid bullae, exclusively caused by S. aureus, often affecting intertriginous areas 2

While Gram stain and culture of exudates can help identify the causative organism, treatment without these studies is reasonable in typical cases 1.

Treatment Algorithm

Limited Disease (Few Lesions)

1. First-line: Topical antibiotics

   • Mupirocin 2% ointment applied twice daily for 5 days 1, 3
   • Retapamulin applied twice daily for 5 days 1

   Clinical efficacy rates for mupirocin in impetigo are approximately 94%, with pathogen eradication rates of 98% 3

Extensive Disease (Multiple Lesions) or Outbreaks

1. First-line: Oral antibiotics for 7 days 1
   • For MSSA (methicillin-susceptible S. aureus):
     • Dicloxacillin or cephalexin 1
   • If MRSA is suspected or confirmed:
     • Clindamycin 1
     • Trimethoprim-sulfamethoxazole (TMP-SMX) 1
     • Doxycycline (for patients ≥8 years old) 1
   • If only streptococci are isolated:
     • Oral penicillin 1

Special Considerations

Pediatric Patients

• Mupirocin is effective and safe for children as young as 2 months 3
• Avoid tetracyclines (doxycycline, minocycline) in children <8 years of age 1
• For hospitalized children with complicated skin infections, vancomycin or clindamycin is recommended 1

Antibiotic Resistance Concerns

• Consider local resistance patterns when selecting empiric therapy 2
• TMP-SMX should not be used as a single agent for initial treatment of cellulitis due to potential streptococcal resistance 1
• Penicillin is inferior to other antibiotics for impetigo treatment 4

Outbreak Management

• During outbreaks of poststreptococcal glomerulonephritis, systemic antibiotics should be used to eliminate nephritogenic strains of S. pyogenes 1
• For sports-related outbreaks, emphasize good hygiene practices, avoid sharing equipment, and promptly identify and treat infected individuals 1

Common Pitfalls to Avoid

1. Undertreating extensive disease: Topical therapy alone is insufficient for widespread impetigo or during outbreaks
2. Using penicillin as first-line therapy: Evidence shows it is inferior to other antibiotics for impetigo 4
3. Failing to consider MRSA: In areas with high MRSA prevalence, empiric therapy should include MRSA coverage
4. Not completing the full course of treatment: Even if symptoms improve quickly, complete the prescribed course to prevent recurrence and resistance

Cochrane review evidence indicates that topical antibiotics show better cure rates than placebo, and topical mupirocin is superior to oral erythromycin 4. The choice between topical and oral therapy should be based on the extent of disease, with topical treatment preferred for limited lesions and oral therapy for extensive disease.