What is the treatment for impetigo?

Treatment of Impetigo

For impetigo, the first-line treatment is topical mupirocin 2% ointment applied three times daily for 5-7 days for limited lesions, while oral antibiotics such as dicloxacillin or cephalexin are recommended for extensive disease. 1

First-Line Treatment: Topical Antibiotics

• Mupirocin 2% ointment is FDA-approved for topical treatment of impetigo due to Staphylococcus aureus and Streptococcus pyogenes, applied three times daily for 5-7 days 2, 1
• Retapamulin 1% ointment is an effective alternative, applied twice daily for 5 days in patients aged 9 months or older 3, 1
• Topical antibiotics have shown better cure rates than placebo (risk ratio 2.24) in clinical studies 4
• Topical therapy is preferred for limited lesions due to fewer systemic side effects compared to oral antibiotics 5

Second-Line Treatment: Oral Antibiotics

Oral antibiotics should be used in the following scenarios:

• Extensive disease with multiple lesions 1, 6
• When topical therapy is impractical 1
• Failure of topical treatment 1
• Presence of systemic symptoms 6

Recommended oral antibiotics:

• For Methicillin-Susceptible S. aureus (MSSA):

  • Dicloxacillin 250 mg four times daily for adults 6
  • Cephalexin 250-500 mg four times daily for adults 6, 1
  • First-generation cephalosporins 1

• For Methicillin-Resistant S. aureus (MRSA):

  • Trimethoprim-sulfamethoxazole 1, 5
  • Clindamycin 300-450 mg three times daily for adults 6, 1
  • Doxycycline (not for children under 8 years) 6, 5

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

Treatment Duration and Follow-up

• Complete the full course of prescribed antibiotics even if symptoms improve quickly 1
• Topical treatment should be used for 5-7 days 6
• Oral antibiotics should be used for 5-10 days 6
• Re-evaluate if no improvement after 48-72 hours of therapy 6

Common Pitfalls and Caveats

• Penicillin alone is not effective for impetigo as it lacks adequate coverage against S. aureus 6, 5
• Oral penicillin V is seldom effective compared to antistaphylococcal penicillins, amoxicillin/clavulanate, cephalosporins, and macrolides 7
• Topical disinfectants are inferior to antibiotics and should not be used 4, 7
• Resistance rates are increasing for commonly used antibiotics, particularly erythromycin 5, 4
• Mupirocin has been shown to be slightly superior to oral erythromycin in multiple studies (risk ratio 1.07) 4

Prevention of Spread

• Lesions should be kept covered with clean, dry bandages 6
• Maintain good personal hygiene to prevent spread 6
• In close-contact settings (schools, military, sports), prompt recognition and treatment are crucial to prevent epidemics 8