What medications are used to treat skin infections?

Medications for Treating Skin Infections

For skin infections, first-line therapy includes dicloxacillin, cephalexin, clindamycin, or amoxicillin-clavulanate, with selection based on suspected pathogens and local resistance patterns. 1

Empiric Antibiotic Selection by Infection Type

Uncomplicated Skin and Soft Tissue Infections

• For typical cellulitis (primarily caused by streptococci), recommended oral antibiotics include penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin 2
• For impetigo, treatment options include dicloxacillin 250 mg four times daily, cephalexin 250 mg four times daily, erythromycin 250 mg four times daily, or mupirocin ointment applied three times daily 1
• For minor skin infections in children, mupirocin 2% topical ointment can be used 3
• For folliculitis, topical benzoyl peroxide is a first-line nonantibiotic treatment, with mupirocin and clindamycin as topical antibiotic options; for treatment-resistant cases, oral cephalexin or dicloxacillin is appropriate 4

Methicillin-Susceptible S. aureus (MSSA) Infections

• Nafcillin or oxacillin 1-2 g every 4 hours IV, or dicloxacillin 500 mg four times daily PO 1
• Cephalexin 500 mg four times daily for adults, and 25-50 mg/kg/day in divided doses for children 1, 5
• Clindamycin 300-450 mg three times daily for adults 1

Methicillin-Resistant S. aureus (MRSA) Infections

• Oral options: linezolid 600 mg twice daily, trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily, doxycycline 100 mg twice daily, or minocycline 3, 1
• For hospitalized patients with complicated SSTI, options include: IV vancomycin, oral or IV linezolid 600 mg twice daily, daptomycin 4 mg/kg/dose IV once daily, telavancin 10 mg/kg/dose IV once daily, and clindamycin 600 mg IV or PO 3 times a day 3
• Tetracyclines should not be used in children <8 years of age 3

Animal or Human Bites

• Amoxicillin-clavulanate 875/125 mg twice daily PO, or ampicillin-sulbactam 1.5-3.0 g every 6-8 hours IV 1
• An antimicrobial agent active against both aerobic and anaerobic bacteria such as amoxicillin-clavulanate should be used 3

Necrotizing Infections

• For mixed infections: piperacillin-tazobactam plus vancomycin, imipenem-cilastatin, meropenem, or ertapenem 3
• For streptococcal infections: penicillin plus clindamycin 3
• For staphylococcal infections: nafcillin, oxacillin, cefazolin, vancomycin (for resistant strains), or clindamycin 3
• For clostridial infections: clindamycin plus penicillin 3

Duration of Therapy and Special Considerations

• For streptococcal infections, a minimum of 10 days of therapy is recommended to prevent rheumatic fever 1
• For uncomplicated cellulitis, a 5-day course of antimicrobial therapy is as effective as a 10-day course if clinical improvement has occurred by day 5 2
• For more severe infections, 7-14 days of therapy is recommended but should be individualized based on clinical response 3, 1
• For MRSA skin infections, 7-14 days of therapy is recommended 3
• IV to oral switch should occur when criteria of clinical stability have been reached 3

Special Populations and Situations

Pediatric Dosing

• Cephalexin: 25-50 mg/kg/day in divided doses 1, 5
• For otitis media, cephalexin dosage of 75-100 mg/kg/day in 4 divided doses is required 5
• In hospitalized children with complicated SSTI, vancomycin is recommended; if the patient is stable without ongoing bacteremia, empirical therapy with clindamycin 10-13 mg/kg/dose IV every 6-8 h is an option if clindamycin resistance is low 3

Recurrent Skin Infections

• Keep draining wounds covered with clean, dry bandages 3
• Maintain good personal hygiene with regular bathing and cleaning of hands 3
• Avoid reusing or sharing personal items that have contacted infected skin 3
• Focus cleaning efforts on high-touch surfaces 3
• Evaluate contacts for evidence of S. aureus infection 3

Common Pitfalls and Caveats

• MRSA is an unusual cause of typical cellulitis according to IDSA guidelines, but coverage may be prudent in cellulitis associated with penetrating trauma, purulent drainage, or concurrent evidence of MRSA infection elsewhere 2
• Cultures from abscesses and other purulent SSTIs are recommended in patients treated with antibiotic therapy, patients with severe local infection or signs of systemic illness, patients who have not responded adequately to initial treatment, and if there is concern for a cluster or outbreak 3
• Local resistance patterns should guide empiric therapy, and culture and sensitivity testing is recommended for treatment failures, recurrent infections, or severe infections 1
• The use of rifampin as a single agent or as adjunctive therapy for the treatment of SSTI is not recommended 3
• For abscesses, furuncles, and carbuncles, management consists primarily of incision and drainage; oral antibiotics are not necessary in most cases but should be prescribed for patients with severe immunocompromise or systemic signs of infection 4