What is the treatment for impetigo lesions?

Treatment of Impetigo Lesions

Impetigo should be treated with topical mupirocin or retapamulin for limited lesions, while oral antibiotics are recommended for extensive disease, with dicloxacillin or cephalexin as first-line options for methicillin-susceptible Staphylococcus aureus (MSSA) and doxycycline, clindamycin, or sulfamethoxazole-trimethoprim (SMX-TMP) for suspected methicillin-resistant Staphylococcus aureus (MRSA). 1

Diagnosis and Causative Organisms

• Impetigo presents as either bullous (30%) or nonbullous (70%) lesions, with nonbullous impetigo caused by Staphylococcus aureus and/or Streptococcus pyogenes, while bullous impetigo is caused exclusively by S. aureus 1, 2
• Gram stain and culture of pus or exudates are recommended to identify the causative organism, though treatment without these studies is reasonable in typical cases 1, 3
• Nonbullous impetigo presents as erythematous papules that evolve into vesicles and pustules that rupture, forming honey-colored crusts on an erythematous base 1, 2
• Bullous impetigo presents with fragile, thin-roofed vesicopustules that may rupture, creating crusted erosions 1, 4

Treatment Algorithm

Limited Impetigo (Few Lesions)

• First-line treatment: Topical antibiotics 1, 3
  • Mupirocin 2% ointment applied three times daily for 5 days (strong, high evidence) 1, 5
  • Retapamulin 1% ointment applied twice daily for 5 days (strong, high evidence) 1, 3
  • Clinical efficacy rates for mupirocin are significantly higher than placebo (71% vs 35%) 5

Extensive Impetigo (Multiple Lesions or Outbreaks)

• First-line treatment: Oral antibiotics for 7 days 1
  • For MSSA (most common): Dicloxacillin or cephalexin (strong, high evidence) 1, 3
  • For suspected or confirmed MRSA: Doxycycline, clindamycin, or SMX-TMP (strong, moderate evidence) 1, 2
  • When cultures yield streptococci alone: Oral penicillin is recommended 1

Special Considerations

• Topical mupirocin has been shown to be slightly superior to oral erythromycin in multiple studies (pooled RR 1.07,95% CI 1.01 to 1.13) 6
• Oral penicillin alone is inferior to erythromycin and cloxacillin for impetigo treatment due to inadequate S. aureus coverage 2, 6
• Systemic antimicrobials should be used during outbreaks of poststreptococcal glomerulonephritis to eliminate nephritogenic strains of S. pyogenes 1

Treatment Duration and Follow-up

• Topical antibiotics should be applied for 5 days 1, 3
• Oral antibiotics should be administered for 7 days 1
• Re-evaluation is necessary if no improvement occurs after 48-72 hours of therapy 3, 4

Common Pitfalls and Caveats

• Topical disinfectants are inferior to antibiotics and should not be used for impetigo treatment 2, 7
• Growing resistance rates for commonly used antibiotics must be considered when selecting treatment 2, 6
• Penicillin alone is not effective for impetigo as it lacks adequate coverage against S. aureus 3, 6
• Side effects are more common with oral antibiotic treatment compared to topical treatment, with gastrointestinal effects accounting for most of the difference 6

Prevention of Spread

• Lesions should be kept covered with clean, dry bandages 3
• Good personal hygiene should be maintained to prevent spread to others 3, 4
• Oral therapy is recommended for outbreaks affecting several people to help decrease transmission of infection 1