What is the appropriate antibiotic dosage for a skin infection of the wrist?

Antibiotic Treatment for Skin Infection of the Wrist

For a skin infection of the wrist, cephalexin 500 mg four times daily for 7-10 days is the recommended first-line treatment for methicillin-susceptible infections. 1

Treatment Algorithm Based on Infection Severity

For Mild to Moderate Uncomplicated Skin Infections:

• First-line oral options:

  • Cephalexin 500 mg four times daily for 7-10 days 1, 2
  • Dicloxacillin 500 mg four times daily for 7-10 days 1
  • Amoxicillin-clavulanate 875/125 mg twice daily for 7-10 days (if mixed aerobic/anaerobic infection suspected) 1

• For penicillin-allergic patients (non-immediate hypersensitivity):

  • Clindamycin 300-450 mg four times daily for 7-10 days 1
  • Doxycycline 100 mg twice daily (not recommended for children under 8 years) 1

For Severe Infections or MRSA Suspected:

• Oral options:

  • Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily 1
  • Clindamycin 300-450 mg four times daily 1
  • Linezolid 600 mg twice daily (expensive, reserved for resistant cases) 1

• Intravenous options (for hospitalized patients):

  • Vancomycin 15 mg/kg every 12 hours 1
  • Cefazolin 1 g every 8 hours (for MSSA) 1
  • Clindamycin 600 mg every 8 hours 1

Special Considerations

For Hand/Wrist Infections:

• Preemptive early antimicrobial therapy for 3-5 days is recommended for moderate to severe injuries to the hand or wrist, especially if they may have penetrated the periosteum or joint capsule 1
• Hand and wrist infections require particular attention due to potential for rapid spread through fascial planes and tendon sheaths 1

For Necrotizing Infections:

• If necrotizing infection is suspected (severe pain disproportionate to findings, wooden feel of tissues, systemic toxicity), immediate surgical consultation and broad-spectrum antibiotics are required 1
• For necrotizing infections, use piperacillin-tazobactam plus vancomycin, or a carbapenem 1

Clinical Pearls and Pitfalls

• Common pitfall: Treating with antibiotics alone without considering incision and drainage for purulent infections. Surgical drainage is the primary treatment for abscesses, with antibiotics as adjunctive therapy 3

• Important consideration: Twice-daily dosing regimens (like amoxicillin-clavulanate) may improve patient compliance compared to four-times-daily regimens (like cephalexin), though both are equally effective 4

• Caution: While cephalosporins have shown clinical success against MRSA in some studies, they do not have accepted in vitro activity against MRSA. Clinical response must be monitored closely 5

• Duration of therapy: Standard duration is 7-10 days, but may need to be extended based on clinical response 1, 6

• Monitoring: Reassess after 48-72 hours to ensure appropriate response to therapy; lack of improvement may indicate need for culture, drainage, or change in antibiotic 3

• Recurrent infections: Consider obtaining cultures to guide antibiotic selection, as recurrent infections may be due to resistant organisms 3

Cephalexin remains a highly effective antibiotic for streptococcal and staphylococcal skin infections, with cure rates of 90% or higher consistently reported 6. For more severe infections or those not responding to initial therapy, broader coverage or intravenous options should be considered based on clinical presentation and local resistance patterns 1.