How should pyoderma be treated with topical and oral antibiotics, including dosing, methicillin‑resistant Staphylococcus aureus coverage, and special considerations for children, pregnant women, and renal impairment?

Treatment of Pyoderma

For limited impetigo (few lesions), apply mupirocin 2% ointment three times daily for 5–7 days; for extensive disease, facial/intertriginous involvement, or systemic symptoms, start oral antibiotics immediately targeting both MSSA and streptococci. 1

Topical Therapy for Limited Disease

Mupirocin 2% ointment is the first-line topical agent:

• Apply three times daily for 5–7 days for limited, localized impetigo 1
• Superior efficacy against both Staphylococcus aureus and Streptococcus pyogenes compared to oral erythromycin 2
• Particularly effective at eradicating antibiotic-resistant S. aureus 2

Retapamulin ointment (twice daily) is an acceptable alternative for patients with a small number of lesions 1

Critical caveat: Topical therapy alone is insufficient when lesions are widespread, involve the face or intertriginous areas, or when systemic symptoms are present 1

Oral Antibiotics for Extensive Disease

For Presumed MSSA (Methicillin-Susceptible S. aureus)

First-line oral agents include:

• Dicloxacillin (standard adult dosing) 1
• Cephalexin (adults: 500 mg four times daily; children: 25–50 mg/kg/day divided) 3
• Amoxicillin-clavulanate 1

Duration: 5–10 days for MSSA-targeted therapy 1

For Suspected or Confirmed MRSA

Clindamycin is preferred when local resistance is <10%:

• Adults: 300–450 mg three to four times daily 3, 1
• Children: 10–13 mg/kg/dose every 6–8 hours (40 mg/kg/day total) 3
• Duration: 7–10 days 1
• Important limitation: Inducible resistance in erythromycin-resistant strains; not reliable if local clindamycin resistance exceeds 10% 3

Trimethoprim-sulfamethoxazole (TMP-SMX):

• Adults: 1–2 double-strength tablets twice daily 3
• Children: 8–12 mg/kg/day based on trimethoprim component in 2 divided doses 3
• Duration: 7–10 days 1
• Critical caveat: Does NOT reliably cover streptococcal infections when used alone 3, 1. Must add a beta-lactam (e.g., amoxicillin) if streptococcal coverage is needed 3

Doxycycline:

• Adults: 100 mg twice daily 3, 1
• Duration: 7–10 days 1
• Absolute contraindication: Children <8 years of age due to dental staining and bone growth effects 3, 1

Linezolid (reserved for resistant cases):

• Adults: 600 mg twice daily IV or PO 3
• Children <12 years: 10 mg/kg every 8 hours 3
• Children ≥12 years: 600 mg twice daily 3

Special Populations

Children

• Mupirocin 2% topical ointment is safe and effective for minor skin infections including impetigo 3
• Tetracyclines (doxycycline, minocycline) are contraindicated in children <8 years 3, 1
• For hospitalized children with complicated SSTI requiring MRSA coverage: vancomycin is recommended, or clindamycin 10–13 mg/kg/dose IV every 6–8 hours if clindamycin resistance is low 3

Pregnant Women

• Beta-lactams (cephalexin, amoxicillin-clavulanate) are generally safe 3
• Avoid tetracyclines (pregnancy category D) 3
• Clindamycin is pregnancy category B and can be used 3

Renal Impairment

• Vancomycin requires dose adjustment based on creatinine clearance and therapeutic drug monitoring 3
• TMP-SMX requires dose reduction in severe renal impairment 3
• Daptomycin (4 mg/kg IV once daily for SSTI) requires dose adjustment in CrCl <30 mL/min 3

Hospitalized Patients with Complicated SSTI

For severe infections requiring IV therapy, empirical MRSA coverage options include:

• Vancomycin (dose adjusted to achieve trough 15–20 mcg/mL for serious infections) 3
• Linezolid 600 mg IV every 12 hours 3
• Daptomycin 4 mg/kg IV once daily 3
• Ceftaroline 600 mg IV twice daily 3

Duration: 7–14 days based on clinical response 3

Abscess Management

Incision and drainage is the primary treatment for skin abscesses 3

• Culture the wound for pathogen identification and antimicrobial susceptibility 3
• Add empirical antibiotic coverage pending culture results, guided by local MRSA prevalence 3

Resistance Considerations

Macrolides (erythromycin) are no longer reliably effective due to increasing resistance among impetigo pathogens 1, 4

Avoid rifampin as monotherapy or adjunctive therapy for SSTI 3

Recurrent Infections

After treating active infection, consider 5-day decolonization regimen:

• Intranasal mupirocin twice daily for 5–7 days 3
• Daily chlorhexidine washes 3
• Daily decontamination of personal items (towels, sheets, clothes) 3

Important caveat: High-level mupirocin resistance (MIC >512 µg/mL) is associated with decolonization failure 3