What is the treatment for skin infections?

Treatment of Skin Infections

The treatment of skin infections requires appropriate antimicrobial therapy targeting the causative pathogens, with specific regimens based on infection type, severity, and suspected organisms, prioritizing incision and drainage for abscesses and antibiotics effective against Gram-positive bacteria for most superficial infections. 1

Classification and Treatment by Infection Type

Superficial Infections (Impetigo, Erysipelas, Cellulitis)

• Impetigo is primarily caused by β-hemolytic Streptococcus and/or Staphylococcus aureus, with increasing prevalence of community-acquired MRSA (CA-MRSA) 1
• Erysipelas presents as a fiery red, tender plaque with well-demarcated edges and is typically caused by streptococcal species, particularly Streptococcus pyogenes 1
• Cellulitis is the most common skin and soft tissue infection (59.1% of cases) and can be caused by streptococci (diffuse, rapidly spreading infection) or staphylococci (more localized infection) 1
• For mild infections without significant comorbidities, oral beta-lactams (amoxicillin-clavulanate, dicloxacilina, cefuroxima, cefalexina) are appropriate in areas where CA-MRSA is not prevalent 1, 2
• Other options include macrolides and lincosamides, though resistance to erythromycin and clindamycin is increasing 1
• For more severe infections, parenteral antibiotics are recommended 1
• If MRSA is suspected (either hospital-acquired or community-acquired), glycopeptides (vancomycin) or newer antimicrobials (linezolid, daptomycin) are the best options 1

Abscesses

• For simple superficial abscesses or boils, incision and drainage is the primary treatment, and antibiotics are not needed 1
• Complex skin and subcutaneous abscesses (perianal, perirectal, and abscesses at injection sites) typically respond to incision and drainage 1
• Antibiotic therapy is recommended if systemic signs of infection are present, in immunocompromised patients, if source control is incomplete, or in cases of abscess with significant cellulitis 1
• Empiric broad-spectrum antibiotic therapy with coverage of Gram-positive, Gram-negative, and anaerobic bacteria is recommended for complex abscesses 1

Necrotizing Infections

• Necrotizing fasciitis requires early and aggressive surgical debridement along with antibiotic therapy 1
• For mixed infections (polymicrobial necrotizing fasciitis), recommended antibiotics include:
  • Ampicillin-sulbactam plus clindamycin plus ciprofloxacin 1
  • Piperacillin-tazobactam plus clindamycin 1
  • Imipenem/cilastatin, meropenem, or ertapenem 1
  • Cefotaxime plus metronidazole or clindamycin 1
• For necrotizing fasciitis caused by group A streptococci, treatment should be with clindamycin and penicillin 1
• For S. aureus infections, nafcillin, oxacillin, cefazolin, or vancomycin (for resistant strains) is recommended 1
• Antibiotic therapy should continue until no further debridement is needed, the patient has shown obvious clinical improvement, and fever has been absent for 48–72 hours 1

Damaged Skin Infections (Bite Wounds, Burns, Pressure Ulcers)

• Irrigation of the wound and debridement of necrotic tissue are the most important factors in preventing infection 1
• Antibiotic prophylaxis is not generally recommended 1
• For patients with systemic signs of infection, compromised immune status, severe comorbidities, associated severe cellulitis, or severe and deep wounds, broad-spectrum antibiotics effective against aerobic and anaerobic organisms are required 1
• Bite wounds (animal and human) have varying infection risks: 30-50% of cat bites, 5-25% of dog bites, and 20-25% of human bites become infected 1

Special Populations

Neutropenic Patients

• Patients with neutropenia are at high risk for skin and soft tissue infections, often due to hematogenous dissemination from other sites 1
• Empirical broad-spectrum antibiotics should be administered at the first clinical signs or symptoms of infection 1
• Excellent results have been reported using broad-spectrum monotherapy with carbapenems, antipseudomonal cephalosporins, or piperacillin/tazobactam 1
• For suspected or confirmed MRSA infections, vancomycin, linezolid, daptomycin, or ceftaroline should be added to the treatment regimen 1
• For fungal infections in neutropenic patients, appropriate antifungal therapy should be added 1

Evidence for Specific Antibiotics

• Linezolid has shown high cure rates (90%) in complicated skin and skin structure infections, comparable to oxacillin (85%) 3
• For MRSA skin infections, linezolid demonstrated a 79% cure rate compared to 73% for vancomycin 3
• In diabetic foot infections, linezolid showed cure rates of 83% in clinically evaluable patients 3

Treatment Algorithm

1. Assess infection type and severity:

   • Simple abscess → Incision and drainage only 1
   • Superficial infection (impetigo, erysipelas, cellulitis) → Antibiotics targeting Gram-positive bacteria 1
   • Complex/severe infection → Broad-spectrum antibiotics + possible surgical intervention 1

2. For superficial infections:

   • Mild cases: Oral beta-lactams (amoxicillin-clavulanate, dicloxacillin) 2
   • If MRSA suspected: Consider trimethoprim-sulfamethoxazole, doxycycline, or clindamycin 1
   • Severe cases: Parenteral therapy (vancomycin, linezolid, daptomycin) 1

3. For complex abscesses:

   • Perform incision and drainage 1
   • Add antibiotics if: systemic signs, immunocompromise, incomplete drainage, or significant cellulitis 1
   • Use broad-spectrum coverage (Gram-positive, Gram-negative, anaerobes) 1

4. For necrotizing infections:

   • Immediate surgical debridement 1
   • Broad-spectrum antibiotics (see specific recommendations above) 1
   • Continue antibiotics until clinical improvement and fever resolution for 48-72 hours 1

Common Pitfalls and Caveats

• Not recognizing necrotizing infections early: These require immediate surgical intervention along with antibiotics; delay increases mortality 1
• Treating simple abscesses with antibiotics: Simple abscesses require only incision and drainage without antibiotics 1
• Inadequate coverage for suspected MRSA: In areas with high MRSA prevalence, empiric coverage should be considered 1
• Overlooking mixed infections: Complex skin infections, especially in damaged skin or diabetic patients, often involve multiple pathogens requiring broad-spectrum coverage 1
• Underestimating the importance of surgical intervention: For abscesses and necrotizing infections, surgical management is critical and antibiotics alone are insufficient 1