Which antibiotic option is listed for preseptal cellulitis in a patient without a penicillin allergy?

Which antibiotic option is listed for preseptal cellulitis in a patient without a penicillin allergy?

• A. Cephalexin 500 mg qid
• B. Clindamycin 450 mg tid
• C. Amoxicillin 500 mg bid
• D. Azithromycin 500 mg daily

Answer: (A)

For preseptal cellulitis in a patient without penicillin allergy, the goal is to cover the common organisms responsible—Staphylococcus aureus (mostly MSSA in uncomplicated cases) and Streptococcus species—with an oral agent that has good tissue penetration and tolerability. A first-generation cephalosporin like cephalexin fits this need well: it provides reliable activity against MSSA and Streptococcus, is well absorbed orally, and is commonly dosed at 500 mg four times daily, making it practical for a short course of therapy. Amoxicillin alone doesn’t reliably cover Staphylococcus aureus, so it risks undertreating the common pathogens. Clindamycin can cover streptococci and staphylococci (including some MRSA), but it carries higher risks of adverse effects, and isn’t preferred as first-line in non-allergic patients. Azithromycin has limited activity against Staphylococcus and Streptococcus and isn’t ideal for this indication due to weaker coverage and resistance concerns.

For preseptal cellulitis in a patient without penicillin allergy, the goal is to cover the common organisms responsible—Staphylococcus aureus (mostly MSSA in uncomplicated cases) and Streptococcus species—with an oral agent that has good tissue penetration and tolerability. A first-generation cephalosporin like cephalexin fits this need well: it provides reliable activity against MSSA and Streptococcus, is well absorbed orally, and is commonly dosed at 500 mg four times daily, making it practical for a short course of therapy.

Amoxicillin alone doesn’t reliably cover Staphylococcus aureus, so it risks undertreating the common pathogens. Clindamycin can cover streptococci and staphylococci (including some MRSA), but it carries higher risks of adverse effects, and isn’t preferred as first-line in non-allergic patients. Azithromycin has limited activity against Staphylococcus and Streptococcus and isn’t ideal for this indication due to weaker coverage and resistance concerns.