Antibiotic Recommendations for Skin Infections
For mild skin and soft tissue infections, first-line antibiotics include amoxicillin-clavulanic acid, cloxacillin, or cephalexin, while more severe infections require targeted therapy based on suspected pathogens and resistance patterns. 1
First-Line Antibiotics for Mild Skin Infections
The WHO Essential Medicines List recommends the following first-choice antibiotics for mild skin and soft tissue infections:
- Amoxicillin-clavulanic acid (oral)
- Cloxacillin (oral) - For oral administration, dicloxacillin and flucloxacillin are preferred due to better bioavailability
- Cephalexin (oral) - Recently upgraded from second to first choice for skin and soft tissue infections 1
These antibiotics provide excellent coverage against the most common pathogens causing skin infections, particularly Staphylococcus aureus and Streptococcus species.
Treatment Based on Specific Infection Types
Uncomplicated Skin Infections
- Duration: 5-7 days 2
- First-line options:
- Dicloxacillin 500 mg orally four times daily
- Amoxicillin-clavulanic acid 875/125 mg orally twice daily
- Cephalexin 500 mg orally four times daily 2
Diabetic Wound Infections
- Mild infections: Dicloxacillin, clindamycin, cephalexin, levofloxacin, amoxicillin-clavulanic acid, or doxycycline 1
- Moderate to severe infections: Levofloxacin, cefoxitin, ceftriaxone, ampicillin-sulbactam, moxifloxacin, ertapenem, tigecycline, or ciprofloxacin with clindamycin 1
Surgical Site Infections
- Trunk/extremity infections: Oxacillin, nafcillin, cefazolin, cephalexin, sulfamethoxazole-trimethoprim, or vancomycin 1
- Axilla/perineum infections: Ceftriaxone or a fluoroquinolone (ciprofloxacin or levofloxacin) combined with metronidazole 1
MRSA Considerations
For suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA) infections:
- Mild infections: Sulfamethoxazole-trimethoprim, clindamycin, doxycycline 1, 2
- Moderate to severe infections: Linezolid, daptomycin, or vancomycin 1, 3
Clinical cure rates for MRSA skin infections with linezolid have been demonstrated at 79% compared to 73% for vancomycin 3.
Necrotizing Fasciitis (Severe Infection)
For this life-threatening infection, combination therapy is recommended:
- Clindamycin plus piperacillin-tazobactam (with or without vancomycin), OR
- Ceftriaxone plus metronidazole (with or without vancomycin) 1
Special Considerations
Penicillin Allergy
- For non-severe allergies: Cephalexin (note: up to 10% of penicillin-allergic patients may also be allergic to cephalosporins) 2
- For severe allergies (anaphylactic-type): Clindamycin (300-450 mg orally three times daily) 2, 4
Renal Impairment
- Dose adjustment required for patients with creatinine clearance less than 30 ml/min when using antibiotics such as amoxicillin-clavulanic acid 2
Pregnancy
- Amoxicillin and cephalexin are generally considered safe (Category B) 2
Treatment Duration
- Uncomplicated skin infections: 5-7 days 2
- Complicated skin infections: 10-14 days 3
- Vancomycin-resistant infections: 14-28 days 3
Monitoring and Follow-up
- Reassess patients within 48-72 hours to evaluate response to treatment 2
- Consider hospitalization and broader antibiotic coverage if:
- No improvement within 48 hours
- Development of systemic symptoms
- Extension of infection 2
Prevention of Recurrence
- Identify and treat predisposing conditions (edema, obesity, eczema, venous insufficiency)
- Optimize glycemic control in diabetic patients
- Consider prophylactic antibiotics for patients with 3-4 episodes per year (options include oral penicillin or erythromycin twice daily) 2
Remember that complete eradication of the infection is crucial to prevent recurrence and complications, so patients should complete the full course of antibiotics as prescribed.