What is the treatment for impetigo (impetigo tx)?

Treatment of Impetigo

For localized impetigo, use topical mupirocin 2% ointment applied three times daily for 5-7 days as first-line therapy; switch to oral antibiotics for extensive disease, treatment failure after 3-5 days, or when topical therapy is impractical. 1, 2

First-Line Topical Treatment

• Mupirocin 2% ointment applied three times daily for 5-7 days is the most effective topical agent for impetigo caused by both S. aureus and S. pyogenes 1, 2, 3
• Retapamulin 1% ointment applied twice daily for 5 days is an effective alternative for limited disease 1
• Avoid bacitracin and neomycin as they are considerably less effective 2
• FDA trials demonstrate 71-93% clinical efficacy with mupirocin versus 35% with placebo, with 94-100% pathogen eradication rates 3

Indications for Oral Antibiotics

Switch to systemic therapy when any of the following are present:

• Extensive disease involving multiple sites 1, 2
• Failure to respond to topical therapy after 3-5 days 2
• Lesions on the face, eyelid, or mouth 2
• Topical therapy is impractical 1
• Systemic symptoms present 1, 2

Oral Antibiotic Selection

For Methicillin-Susceptible S. aureus (MSSA):

• Dicloxacillin 250 mg four times daily for adults 1, 2
• Cephalexin 250-500 mg four times daily for adults 1, 2
• Penicillin alone is NOT effective for impetigo due to inadequate S. aureus coverage 1, 2

For Methicillin-Resistant S. aureus (MRSA):

• Clindamycin 300-450 mg three times daily for adults 1, 2
• Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily for adults 1, 2
• Doxycycline (avoid in children under 8 years) 1

Duration:

• Oral antibiotics should be given for 5-10 days 1, 2

Pediatric Considerations

• Adjust all oral antibiotic dosing by weight for children 1
• Never use tetracyclines (doxycycline, minocycline) in children under 8 years of age 1, 2
• Cephalexin is a safe alternative for pregnant patients 2
• Pediatric efficacy rates with mupirocin are 78-96% 3

When to Obtain Cultures

Obtain cultures from vesicle fluid, pus, or erosions if:

• Treatment failure occurs 1, 2
• MRSA is suspected 1, 2
• Recurrent infections are present 1, 2

Prevention of Spread

• Keep lesions covered with clean, dry bandages 1, 2
• Maintain good personal hygiene with regular handwashing 2
• Avoid sharing personal items that contact the skin 2

Critical Pitfalls to Avoid

• Do not use penicillin alone - it lacks adequate S. aureus coverage 1, 2
• Do not use topical disinfectants as they are inferior to antibiotics 2
• Re-evaluate if no improvement after 48-72 hours of therapy 1
• Consider alternative diagnoses if impetigo is not responding to appropriate therapy 1
• Clindamycin is the preferred alternative for penicillin-allergic patients 2

Treatment Algorithm

Limited disease (few lesions, localized):

• Start with mupirocin 2% ointment three times daily for 5-7 days 1, 2

Extensive disease or topical therapy impractical:

• Use oral antibiotics active against both S. aureus and streptococci 1
• Choose dicloxacillin or cephalexin for MSSA 1, 2
• Choose clindamycin or TMP-SMX for suspected MRSA 1, 2

Treatment failure:

• Obtain cultures and adjust therapy based on susceptibility results 1, 2