Which antibiotic is listed for dacryoadenitis in a patient with a penicillin allergy?

• A. Clindamycin 300 mg tid
• B. Cephalexin 500 mg qid
• C. Amoxicillin 500 mg bid
• D. Doxycycline 100 mg bid

Answer: (A)

When treating dacryoadenitis in a patient with a penicillin allergy, the goal is to use a non–beta-lactam antibiotic that reliably covers the common pathogens causing lacrimal gland infections, primarily Staphylococcus aureus and Streptococcus species, while avoiding any drug class that could trigger the allergy.

Clindamycin fits because it provides good coverage against Staph (including strains that might be penicillinase-producing) and Streptococcus, and it is a non–beta-lactam antibiotic safe to use in penicillin-allergic patients. Its oral form with a typical regimen around 300 mg every 6 hours offers effective lacrimal tissue penetration, making it a practical and reliable choice for this scenario.

Cephalexin is a beta-lactam (a cephalosporin). Even though cross-reactivity with penicillin is not absolute, it raises concern in a patient with a true penicillin allergy, so it’s avoided in this context. Amoxicillin is clearly a penicillin derivative and would be inappropriate for someone with a penicillin allergy. Doxycycline can be used in some ocular infections and covers MRSA, but it’s less ideal for acute dacryoadenitis as a first-line choice due to age-related restrictions (not preferred in children) and differing safety profiles, making clindamycin the better targeted option in this situation.