What to do if a patient allergic to penicillin (antibiotic) reacts to Polysporin (polymyxin B and trimethoprim) eye drops?

Management of Polysporin Eye Drop Reactions in Patients with Penicillin Allergy

For patients with penicillin allergy who react to Polysporin (polymyxin B and trimethoprim) eye drops, discontinue the eye drops immediately and consider alternative antibiotic eye drops that do not contain polymyxin B. 1

Understanding the Reaction

• Polysporin eye drops contain polymyxin B and trimethoprim, neither of which are beta-lactam antibiotics or structurally related to penicillin 1
• Local reactions to Polysporin eye drops are common and include increased redness, burning, stinging, and itching 1
• Hypersensitivity reactions may present as lid edema, itching, increased redness, tearing, and/or circumocular rash 1
• These reactions are not related to penicillin allergy and represent a separate hypersensitivity to one of the components in the eye drops 1, 2

Immediate Management

• Discontinue Polysporin eye drops if any sensitivity reaction occurs 1, 2
• Rinse the eye thoroughly with sterile saline or artificial tears to remove residual medication 1
• Treat symptomatic reactions with:
  • Cold compresses for lid edema and inflammation 1
  • Preservative-free artificial tears for irritation 1

Alternative Antibiotic Options

For Patients with Penicillin Allergy:

• Fluoroquinolone eye drops (e.g., ciprofloxacin, moxifloxacin) are safe alternatives with no cross-reactivity with penicillins 3, 4
• Aminoglycoside eye drops (e.g., gentamicin, tobramycin) can be used with no cross-reactivity concerns 4
• Erythromycin ophthalmic ointment is another option with no beta-lactam cross-reactivity 4

Important Considerations:

• The reaction to Polysporin is likely unrelated to the patient's penicillin allergy, as polymyxin B and trimethoprim are structurally distinct from beta-lactams 5
• For future antibiotic needs, consider that:
  • Carbapenems have only 0.87% cross-reactivity with penicillins and can be used without prior allergy testing 6, 4
  • Cephalosporins with dissimilar side chains to penicillins have low cross-reactivity (2.11%) 4
  • Aztreonam can be safely administered to patients with penicillin allergy 4

Follow-up Recommendations

• Document the reaction to Polysporin eye drops in the patient's medical record 1
• Consider referral to an allergist if the reaction was severe or if clarification of the patient's penicillin allergy status would benefit future antibiotic selection 7, 8
• For patients with documented penicillin allergy who need future beta-lactam antibiotics, note that:
  • Many reported penicillin allergies are not clinically significant when challenged 5, 8
  • Oral amoxicillin challenge in a controlled setting can safely confirm or refute penicillin allergy in low-risk patients 8

Special Considerations for Ophthalmic Use

• Ophthalmic administration of antibiotics results in minimal systemic absorption, reducing the risk of systemic allergic reactions 9
• Even patients with documented systemic antibiotic allergies rarely experience allergic reactions to intravitreal antibiotics 9
• Alternative ophthalmic antibiotics should be selected based on the suspected pathogen and local antimicrobial resistance patterns 10