Influence of Topical Anesthesia on Superficial Sensitivity: A Double-Blind, Randomized, Placebo-Controlled Study on 48 Healthy Subjects.

Background: Topical anesthetics are used in noninvasive transdermal anesthesia to decrease the superficial pain sensation threshold during dermatologic surgery. Combined pain relief and sensitivity loss can avoid discomfort during the surgery.

Objective: The aim of this placebo-controlled study was to compare the efficacy of 3 commonly used topical agents by collating loss of sensitivity over time.

Materials And Methods: Three topical anesthetic creams, a topical anti-inflammatory cream, and a moisturizing cream were applied on the left volar forearm of each of the 48 healthy Caucasian participants. Sensitivity was assessed with the dynamic 2-point discrimination and the Semmes-Weinstein test at 0, 60, 90, 120, 150, and 180 minutes after cream application.

Results: After 180 minutes, benzocaine showed a significantly lower 2-point discrimination reduction than lidocaine alone and a lidocaine and prilocaine mixture. Sensory threshold measurements by the Semmes-Weinstein test after 60 minutes revealed a significantly higher effect with lidocaine alone and with the lidocaine and prilocaine mixture than with benzocaine.

Conclusion: The authors found a stronger skin sensitivity reduction by the eutectic lidocaine and prilocaine mixture and lidocaine alone compared with benzocaine. We suggest increased discomfort reduction in topical anesthetic supported dermatologic surgery by the eutectic mixture and lidocaine alone.