What is the treatment for a skin infection?

Treatment of Skin Infections

The treatment of skin infections should begin with identification of the causative pathogen, followed by appropriate antibiotic therapy targeting Staphylococcus aureus and Streptococcus species, which are the most common causative organisms. 1

Diagnosis

• Determine the etiology of the skin infection by aspiration and/or biopsy of skin lesions when appropriate, especially in immunocompromised patients 1
• The differential diagnosis should include bacterial, fungal, viral, and parasitic agents 1
• Blood cultures are unnecessary for typical cases of cellulitis but should be obtained for patients with malignancy, severe systemic features, or unusual predisposing factors 1

Treatment Algorithm for Bacterial Skin Infections

Uncomplicated Skin Infections (Cellulitis, Impetigo)

• First-line therapy: Beta-lactam antibiotics
  • Penicillinase-resistant penicillins (dicloxacillin 500 mg four times daily) 1
  • First-generation cephalosporins (cephalexin 500 mg three times daily) 1
  • Amoxicillin-clavulanate (875/125 mg twice daily) 1
• Duration: 5-7 days is sufficient if clinical improvement occurs 1
• For penicillin-allergic patients: Clindamycin (300 mg three times daily) 1

MRSA Consideration

• MRSA is an unusual cause of typical cellulitis but should be considered in specific situations 1
• Consider coverage for MRSA in:
  • Cellulitis with penetrating trauma
  • Presence of purulent drainage
  • Evidence of MRSA infection elsewhere 1
• Options for MRSA treatment:
  • Oral: Trimethoprim-sulfamethoxazole, doxycycline, or clindamycin 1
  • Intravenous: Vancomycin, daptomycin, linezolid, or telavancin 1

Skin Abscesses

• Primary treatment: Incision and drainage 1
• Obtain cultures for identification of causative agent and antimicrobial susceptibility 1
• Empiric antibiotic coverage should be guided by local MRSA prevalence 1
• For methicillin-susceptible S. aureus: First or second-generation cephalosporins 1
• For suspected MRSA: Trimethoprim-sulfamethoxazole, doxycycline, or clindamycin for susceptible isolates 1

Severe or Complicated Infections

• Hospitalization should be considered for patients with:
  • Systemic toxicity (fever, tachycardia, hypotension)
  • Elevated laboratory markers (creatinine, creatine phosphokinase >2-3× normal, C-reactive protein >13 mg/L)
  • Signs of deep tissue infection 1
• Warning signs of severe infection requiring urgent surgical evaluation:
  • Pain disproportionate to physical findings
  • Violaceous bullae
  • Cutaneous hemorrhage
  • Skin sloughing
  • Skin anesthesia
  • Rapid progression
  • Gas in the tissue 1

Special Populations

Immunocompromised Patients

• Consult with a dermatologist familiar with cutaneous manifestations of infection in immunocompromised patients 1
• Consider early biopsy and surgical debridement 1
• Empiric antibiotics, antifungals, and/or antivirals should be considered in life-threatening situations 1
• For patients with neutropenia:
  • Determine if this is an initial, persistent, or recurrent episode of fever and neutropenia 1
  • Aggressively determine the etiology through aspiration and/or biopsy 1
  • Consider empiric antifungal therapy for persistent or recurrent fever 1

Pediatric Patients and Athletes

• For children with skin infections:
  • Exclude from close contact sports until appropriate treatment has been initiated 1
  • Return to sports after 24 hours of appropriate antimicrobial therapy for streptococcal infections 1
• For skin infections in athletes:
  • Emphasize good hygiene practices
  • Avoid sharing equipment and water bottles
  • Promptly identify and treat infected individuals 1

Prevention of Recurrent Infections

• Address predisposing factors such as edema, venous insufficiency, and tinea pedis 1
• Consider antimicrobial prophylaxis for patients with recurrent episodes 1

Common Pitfalls and Caveats

• Failure to recognize deep tissue involvement can lead to significant morbidity and mortality 1
• Empiric treatment without appropriate cultures may miss resistant organisms 1
• Treatment failure may occur due to:
  • Incorrect initial diagnosis
  • Pathogen resistance to antimicrobial agent
  • Development of resistance during treatment
  • Lack of surgical intervention when indicated
  • Profound immune deficiency 1
• Doxycycline and trimethoprim-sulfamethoxazole should not be used as single agents for cellulitis due to possible streptococcal resistance 1
• Trimethoprim-sulfamethoxazole should not be used as a single agent in the initial treatment of cellulitis because of the possibility of intrinsic resistance of group A Streptococcus 1