How is Mupirocin (mupirocin) used to treat impetigo?

Mupirocin for Impetigo Treatment

Topical mupirocin 2% ointment applied twice daily for 5 days is the recommended first-line treatment for impetigo with limited lesions, as it effectively targets both Staphylococcus aureus and Streptococcus pyogenes, the primary causative pathogens. 1, 2

Pathophysiology and Causative Organisms

• Impetigo can present in two forms: bullous (caused by S. aureus) and nonbullous (caused by S. aureus, S. pyogenes, or both) 1
• Bullous impetigo presents as thin-roofed vesicopustules that rupture, leaving crusted erosions 1
• Nonbullous impetigo begins as erythematous papules that evolve into vesicles and pustules, which rupture and form characteristic honey-colored crusts 1

Diagnostic Approach

• Gram stain and culture of pus or exudates from skin lesions can help identify the causative organism, though treatment without these studies is reasonable in typical cases 1
• Clinical diagnosis is often sufficient based on the characteristic appearance of honey-colored crusts on an erythematous base 1

Treatment Options

Topical Therapy

• Mupirocin 2% ointment applied twice daily for 5 days is highly effective for limited impetigo lesions 1, 2
• Mupirocin has excellent in vitro activity against staphylococci and streptococci, the predominant pathogens in impetigo 3, 4
• Topical application delivers high drug concentrations directly to the infection site with minimal systemic absorption 5
• Retapamulin is an alternative topical agent with similar efficacy 1

Oral Antibiotic Therapy

• Oral antibiotics are recommended for patients with numerous lesions or during outbreaks affecting several people to help decrease transmission 1
• First-line oral options include:
  • Dicloxacillin (250 mg 4 times daily for adults; 12 mg/kg/day in 4 divided doses for children) 1
  • Cephalexin (250 mg 4 times daily for adults; 25 mg/kg/day in 4 divided doses for children) 1
• For penicillin-allergic patients or MRSA infections, alternatives include:
  • Clindamycin (300-450 mg 3 times daily for adults; 10-20 mg/kg/day in 3 divided doses for children) 1
  • Doxycycline (100 mg twice daily, not recommended for children under 8 years) 1
  • Trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily for adults) 1

Treatment Duration

• Standard treatment duration for impetigo is 5-7 days 1
• Treatment should be extended if the infection has not improved within this time period 1

Special Considerations

• Systemic antimicrobials should be used during outbreaks of poststreptococcal glomerulonephritis to eliminate nephritogenic strains of S. pyogenes from the community 1
• For recurrent impetigo, consider a 5-day decolonization regimen with twice-daily intranasal mupirocin, daily chlorhexidine washes, and decontamination of personal items 1

Advantages of Mupirocin

• Unique chemical structure and mechanism of action (inhibits bacterial protein and RNA synthesis) reduces likelihood of cross-resistance 3, 5
• Fewer adverse effects than systemic antibiotics (local reactions in <3% of patients) 3, 6
• Cost-effective and easier to administer than oral antibiotics 6
• Provides a reliable topical alternative to oral therapy with equivalent efficacy 7

Prevention of Recurrence and Spread

• Keep draining wounds covered with clean, dry bandages 1
• Maintain good personal hygiene with regular handwashing 1
• Avoid sharing personal items like towels and razors 1
• Evaluate close contacts for evidence of infection 1

Mupirocin's excellent efficacy against the causative pathogens of impetigo, combined with its favorable safety profile and ease of use, makes it an ideal first-line treatment for localized impetigo lesions, while oral antibiotics are preferred for more extensive disease.