Can neomycin (neomycin), polymyxin B (polymyxin B), and fluocinolone (fluocinolone) ear drops cause an allergic reaction on the skin, such as red spots on the chin, when used as directed in the ear?

Neomycin-Containing Ear Drops Can Cause Allergic Skin Reactions Including on the Chin

Yes, neomycin, polymyxin B, and fluocinolone ear drops can cause allergic contact dermatitis that may manifest as red spots on the chin, even when only applied to the ear. This occurs through contact spread of the medication to other areas of skin.

Mechanism of Allergic Reactions to Topical Ear Medications

• Neomycin is particularly problematic, with a 13% to 30% prevalence of contact sensitivity in patients with chronic otitis externa 1

• The allergic reaction develops in two phases:

  • Initial sensitization phase (10-14 days)
  • Subsequent delayed-type hypersensitivity reaction upon re-exposure

• Key characteristics of this allergic reaction:

  • Can extend beyond the ear canal to involve skin around the ear and neck
  • Manifests as erythema, pruritus, inflammation, edema, and sometimes blisters
  • Occurs wherever contact is made with the medication 1

Components That Commonly Cause Allergic Reactions

1. Active ingredients:

   • Neomycin (most common allergen - 16.2% of cases) 2
   • Polymyxin B (4.2% of cases) 2
   • Fluocinolone (a corticosteroid that can cause sensitization)

2. Preservatives and vehicles:

   • Propylene glycol
   • Thimerosal
   • Benzalkonium chloride
   • Other preservatives 1

How the Reaction Spreads to the Chin

The allergic reaction can spread to the chin through:

• Direct transfer via fingers after touching the ear/medication
• Medication running down from the ear during application
• Pillow contact during sleep after application
• Touching the ear and then touching the chin

Clinical Implications and Management

If red spots appear on the chin after using these ear drops:

1. Discontinue the medication immediately

   • The FDA drug label for neomycin explicitly states: "Discontinue this product promptly if sensitization or irritation occurs" 3

2. Alternative treatment options:

   • Switch to fluoroquinolone-containing ear drops (e.g., ofloxacin)
     • These have lower risk of allergic reactions
     • Do not contain potentially sensitizing aminoglycosides 4

3. For existing reactions:

   • Topical corticosteroids may help manage the allergic dermatitis
   • Avoid further exposure to the allergen

Prevention of Future Reactions

• Document the allergy to neomycin and related compounds
• Avoid all topical preparations containing neomycin, polymyxin B, and related compounds
• Consider patch testing to confirm specific allergens 5
• Be aware that simultaneous allergies to multiple antibiotics (neomycin, bacitracin, polymyxin) can occur 6

Important Considerations

• Allergic contact dermatitis is more common with prolonged use of topical antibiotics
• The American Academy of Otolaryngology-Head and Neck Surgery notes that contact sensitivity is a known complication of topical therapy for otitis externa 7
• The risk of sensitization means neomycin-containing preparations should not be used routinely 5

Remember that once sensitization has occurred, even brief exposure to the allergen can trigger a more pronounced inflammatory response that extends beyond the application site 1.