Glyceryl p-aminobenzoate patch testing in benzocaine-sensitive subjects

Area of Science:

• Dermatology
• Allergology
• Contact dermatitis

Background:

• Benzocaine is a common topical anesthetic.
• Contamination of other substances with benzocaine can occur.
• Identifying sources of allergic reactions is crucial for patient management.

Purpose of the Study:

• To investigate the reactivity of benzocaine-allergic patients to varying concentrations of benzocaine contaminant in glyceryl p-aminobenzoate.
• To determine a threshold for benzocaine contamination that elicits allergic contact dermatitis.

Main Methods:

• Patch testing was performed on benzocaine-sensitized individuals.
• Two commercial glyceryl p-aminobenzoate samples with different benzocaine contaminant levels (approx. 0.3% and 0.001%) were used.
• Patient reactions were recorded.

Main Results:

• Eleven out of 20 patients reacted to the glyceryl p-aminobenzoate sample containing approximately 0.3% benzocaine.
• No patients reacted to the sample with approximately 0.001% benzocaine.
• This suggests a concentration-dependent reaction.

Conclusions:

• Benzocaine contamination in glyceryl p-aminobenzoate can trigger allergic reactions in sensitized individuals.
• Lower levels of benzocaine contamination (around 0.001%) may be tolerated by benzocaine-allergic patients.
• Minimizing benzocaine contamination in related products is important for preventing allergic contact dermatitis.