What is the treatment for a skin infection without an abscess?

Treatment for Skin Infections Without Abscess

For skin infections without abscess (erysipelas, cellulitis, impetigo), antibiotics targeting Gram-positive bacteria, particularly streptococci and Staphylococcus aureus, are the primary treatment. 1

Classification and Causative Organisms

• Cellulitis is an acute bacterial infection of the dermis and subcutaneous tissue, most commonly affecting lower extremities, presenting with warmth, erythema, pain, and sometimes systemic symptoms 1
• Erysipelas is characterized by a fiery red, tender plaque with well-demarcated edges, primarily caused by streptococcal species, especially Group A Streptococcus 1
• Impetigo is a highly contagious superficial infection with discrete purulent lesions, caused by β-hemolytic Streptococcus and/or S. aureus 1

Treatment Algorithm

For Outpatient Management of Nonpurulent Cellulitis:

1. First-line therapy:

   • Oral beta-lactams (targeting β-hemolytic streptococci) for mild, early infections without significant comorbidities in areas where CA-MRSA is not prevalent 1
   • Treatment duration: 5-10 days, based on clinical response 1

2. If no response to beta-lactam therapy or patient has systemic toxicity:

   • Add empiric coverage for CA-MRSA 1

3. For patients at risk for CA-MRSA initially:

   • Consider empiric coverage for both streptococci and MRSA 1

Oral Antibiotic Options:

• For streptococcal coverage only:

  • Beta-lactams (e.g., amoxicillin) 1

• For CA-MRSA coverage:

  • Clindamycin (300-450 mg every 6 hours for severe infections) 2
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 1
  • Tetracyclines (doxycycline or minocycline) - not for children <8 years 1
  • Linezolid 1

• For dual coverage (streptococci and CA-MRSA):

  • Clindamycin alone 1
  • TMP-SMX or tetracycline plus beta-lactam 1
  • Linezolid alone 1

For Severe Infections Requiring Hospitalization:

• Parenteral antibiotics are recommended 1
• Options include:
  • IV vancomycin 1
  • IV/PO linezolid 1
  • IV daptomycin 1
  • IV telavancin 1
  • IV/PO clindamycin 1

For Pediatric Patients:

• For minor skin infections: mupirocin 2% topical ointment 1
• For more significant infections requiring systemic therapy:
  • Clindamycin 8-16 mg/kg/day divided into three or four doses for serious infections; 16-20 mg/kg/day for more severe infections 2
  • Avoid tetracyclines in children <8 years of age 1

Special Considerations

• For impetigo: Topical mupirocin may be sufficient for localized, non-bullous cases 1

• For MRSA risk assessment: Consider local prevalence, previous MRSA infection, recent hospitalization, recent antibiotic use (especially beta-lactams, carbapenems, quinolones), residence in long-term care facilities, and age >75 years 1

• For immunocompromised patients or those with systemic symptoms: Consider broader spectrum coverage and possible hospitalization 1

Common Pitfalls to Avoid

• Misdiagnosis: Failing to differentiate between purulent and nonpurulent infections, which require different antibiotic approaches 1

• Inadequate coverage: TMP-SMX alone is not recommended for initial treatment of nonpurulent cellulitis due to possible intrinsic resistance of Group A Streptococcus 1

• Inappropriate use of rifampin: Not recommended as monotherapy or adjunctive therapy for skin infections due to rapid development of resistance 1

• Overtreatment: Using broad-spectrum antibiotics when narrow-spectrum would suffice, particularly in mild cases 1

• Underestimating severity: Failing to recognize signs of systemic illness that would warrant hospitalization and parenteral therapy 1