What is the appropriate treatment for a patient with a Methicillin-Sensitive Staphylococcus aureus (MSSA) skin abscess who is allergic to penicillin (PCN), considering the use of cefuroxime?

Treatment of MSSA Skin Abscess in Penicillin-Allergic Patients

Cefuroxime is NOT the optimal choice for MSSA skin abscess in penicillin-allergic patients; instead, use a first-generation cephalosporin (cefazolin) for non-anaphylactic penicillin allergy, or trimethoprim-sulfamethoxazole, doxycycline, or clindamycin if MRSA coverage is needed or if true anaphylactic allergy exists. 1

Primary Management: Incision and Drainage

• Skin abscesses are best managed by incision and drainage, with culture of the wound for identification of causative agent and antimicrobial susceptibility pattern. 1
• Empirical antibiotic coverage should be initiated pending culture results, guided by local MRSA prevalence. 1

Antibiotic Selection Based on Allergy Type

For Non-Anaphylactic Penicillin Allergy (Simple Rash)

• First-generation cephalosporins such as cefazolin are reasonable for patients with well-defined history of non-anaphylactoid reactions to penicillins (e.g., simple skin rash). 1
• Cefazolin is preferred over cefuroxime (a second-generation cephalosporin) because it has better anti-staphylococcal activity and is specifically recommended in guidelines for MSSA infections. 1
• The cross-reactivity risk between penicillins and first-generation cephalosporins is approximately 1-3% for non-anaphylactic reactions. 2

For Anaphylactic Penicillin Allergy

• Cephalosporins are contraindicated in patients with immediate-type hypersensitivity (urticaria, angioedema, bronchospasm, or anaphylaxis). 2
• Alternatives include trimethoprim-sulfamethoxazole, doxycycline, or clindamycin for susceptible MSSA isolates. 1
• Doxycycline can be used safely in children ages 2 years and older when given for durations less than 2 weeks. 1

Why Cefuroxime Is Suboptimal

• Cefuroxime (a second-generation cephalosporin) has inferior anti-staphylococcal activity compared to first-generation cephalosporins like cefazolin. 3
• Guidelines specifically recommend first-generation cephalosporins or penicillinase-resistant penicillins for MSSA, not second-generation agents. 1
• The FDA labeling for cefuroxime indicates it should be given cautiously to penicillin-sensitive patients, acknowledging cross-reactivity concerns. 3

MRSA Considerations

• If local MRSA rates are significant or if MRSA is suspected, empirical coverage with trimethoprim-sulfamethoxazole, doxycycline, or clindamycin is appropriate. 1
• Trimethoprim-sulfamethoxazole should not be used as a single agent for initial treatment of cellulitis due to intrinsic resistance of group A Streptococcus. 1
• Once culture confirms MSSA, narrow therapy to a first-generation cephalosporin (if non-anaphylactic allergy) or continue with trimethoprim-sulfamethoxazole/doxycycline/clindamycin (if anaphylactic allergy). 1

Critical Pitfalls to Avoid

• Do not use vancomycin for MSSA when beta-lactams can be used, as beta-lactams have superior efficacy and vancomycin is associated with poorer outcomes in MSSA infections. 1, 4, 5
• Do not continue broad-spectrum antibiotics once MSSA is confirmed, as this increases antimicrobial resistance and Clostridioides difficile risk without improving outcomes. 6
• Clindamycin has been associated with treatment failure in serious staphylococcal infections and should be used cautiously. 1
• Always obtain cultures to guide de-escalation therapy and monitor local resistance patterns. 1, 7

Allergy Evaluation Recommendation

• Consider allergy evaluation with penicillin skin testing in patients with questionable or remote penicillin allergy history, as most patients reporting penicillin allergy are not truly allergic. 1, 4, 5
• Allergy/Immunology consultation is the single most important predictor of optimal therapy in penicillin-allergic patients with staphylococcal infections. 5
• If skin testing is negative, first-line beta-lactam therapy (nafcillin, oxacillin, or cefazolin) can be safely administered. 4