[Allergic contact dermatitis from lidocaine in ear drops]

Area of Science:

• Dermatology
• Allergology
• Pharmacology

Background:

• Lidocaine is a widely utilized local anesthetic administered via topical or parenteral routes.
• While uncommon, allergic contact dermatitis (ACD) to lidocaine has seen a rise in reported cases.
• Understanding lidocaine's allergenic potential is crucial for patient safety and clinical practice.

Observation:

• A 66-year-old male developed acute dermatitis affecting the ear (pinna) and cheek.
• The patient's symptoms appeared subsequent to the application of ear drops.
• Clinical presentation suggested a localized hypersensitivity reaction.

Findings:

• Patch testing confirmed the patient's allergy.
• Positive reactions were observed for both the specific ear drop product and pure lidocaine.
• This definitively diagnosed contact dermatitis caused by lidocaine.

Implications:

• Highlights the importance of considering lidocaine as a potential allergen in contact dermatitis cases.
• Suggests a need for increased awareness among healthcare providers regarding lidocaine allergy.
• Emphasizes the diagnostic value of patch testing for identifying specific contact allergens like lidocaine.