What is the recommended treatment for impetigo?

Treatment of Impetigo

For limited impetigo, start with topical mupirocin 2% ointment applied three times daily for 5-7 days; switch to oral antibiotics (dicloxacillin, cephalexin, or clindamycin) if lesions are extensive, involve the face/eyelid/mouth, fail to respond after 3-5 days, or if systemic symptoms are present. 1

First-Line Topical Treatment

• Mupirocin 2% ointment applied three times daily is the most effective topical agent for impetigo caused by S. aureus and S. pyogenes, with FDA approval for this indication 1, 2
• Retapamulin is an alternative topical option for patients 9 months or older, though it only covers methicillin-susceptible S. aureus 1, 3
• Topical antibiotics are significantly more effective than placebo (RR 2.24) and superior to disinfectant solutions 4, 5
• Avoid bacitracin and neomycin—they are considerably less effective and should not be used 1
• Never use topical clindamycin cream for impetigo, as it lacks FDA indication for this condition and has insufficient bioavailability (only 4%) to treat bacterial skin infections 1
• Duration of topical therapy should be 5-7 days 1

When to Switch to Oral Antibiotics

Indications for oral antibiotics include: 1

• Extensive disease (multiple lesions or large affected areas)
• Lesions on the face, eyelid, or mouth
• Failure to respond to topical therapy after 3-5 days
• Presence of systemic symptoms (fever, malaise)
• Need to limit spread to others in high-transmission settings

Oral Antibiotic Selection

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

• Dicloxacillin 250 mg four times daily for adults (12 mg/kg/day in 4 divided doses for children) 1, 6
• Cephalexin 250-500 mg four times daily for adults (25 mg/kg/day in 4 divided doses for children) 1, 6
• Amoxicillin-clavulanate 875/125 mg twice daily for adults (25 mg/kg/day of amoxicillin component in 2 divided doses for children) 6
• Cefdinir can be considered as an alternative oral cephalosporin 6

For Suspected or Confirmed MRSA:

• Clindamycin 300-450 mg three times daily for adults (10-20 mg/kg/day in 3 divided doses for children) 1, 6
• Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily for adults (8-12 mg/kg/day based on trimethoprim component in 2 divided doses for children) 1, 6
• Doxycycline 100 mg twice daily for adults (avoid in children under 8 years) 6

Critical Antibiotic Considerations:

• Penicillin alone is not effective for impetigo as it lacks adequate coverage against S. aureus 1, 6
• Macrolides (erythromycin) have increasing resistance rates and should be used with caution 6
• Duration of oral antibiotic therapy should be 5-10 days 1, 6

Comparative Effectiveness

• Topical mupirocin is slightly superior to oral erythromycin (RR 1.07) 4
• Mupirocin and fusidic acid have similar efficacy with no significant difference between them 1, 4, 5
• Penicillin is inferior to erythromycin (RR 1.29) and cloxacillin (RR 1.59) 4

Treatment Failure Management

If impetigo is refractory to mupirocin: 6

• Initiate oral antibiotics immediately (dicloxacillin, cephalexin, clindamycin, or amoxicillin-clavulanate)
• Consider mupirocin resistance, especially in high MRSA prevalence areas
• Obtain cultures from lesions to guide therapy
• Re-evaluate if no improvement after 48-72 hours of oral therapy
• Consider hospitalization with IV antibiotics (vancomycin for MRSA, clindamycin 10-13 mg/kg/dose IV every 6-8 hours if local clindamycin resistance <10%) for severe treatment failure 6

Special Population Considerations

• Pregnant patients: Cephalexin is generally safe; avoid tetracyclines 1, 6
• Children under 8 years: Avoid doxycycline and all tetracyclines 1, 6
• Recurrent infections: Consider decolonization strategies for S. aureus carriers and obtain cultures 1, 6

Prevention of Spread

• Keep lesions covered with clean, dry bandages 1
• Maintain good personal hygiene with regular handwashing 1
• Avoid sharing personal items that contact the skin 1

Common Pitfalls to Avoid

• Do not use disinfectant solutions alone—they are inferior to antibiotics 4
• Do not prescribe topical clindamycin cream (formulated for acne, not impetigo) 1
• Side-effects are more common with oral antibiotics (primarily gastrointestinal) compared to topical treatment, though overall rates remain low 4
• Growing bacterial resistance worldwide necessitates culture-guided therapy in treatment failures 1, 7