Ethyl Chloride Spray to Reduce Pain From Local Anesthesia During Mohs Micrographic Surgery

Fear of needles is a well-documented issue that affects many patients. This fear may cause significant anxiety in various medical situations, including in the dermatology office 1. If not properly managed, needle phobia can persist, affecting a patient's experience during each visit. This effect may compound and lead to avoidance behaviors that can delay necessary treatments 2. This issue is particularly relevant in a Mohs micrographic surgery (MMS) clinic where each patient experiences several painful needle injections before the day is over. Ethyl chloride is gaining popularity among dermatologists for its routine use in clinical practice due to its anesthetic and antiseptic properties, especially as a pre-injection agent. Research indicates that cryotherapy or pre-cooling the skin before administering a local anesthetic may offer benefits over topical anesthetics, such as enhanced pain relief, quicker onset, and better patient compliance 3,4. However, to our knowledge, no studies have specifically examined the effectiveness of pre-cooling with ethyl chloride prior to Mohs micrographic surgery. To address this gap, we're conducting a trial aimed at evaluating the impact of pre-cooling with ethyl chloride on pain perception in adult patients undergoing Mohs micrographic surgery with local anesthetic injections. The trial is a single-center, split-body study. The split-body design will involve dividing the surgical site into two equal halves, with one half (right side relative to patient) designated as the treatment side (receiving ethyl chloride spray prior to lidocaine injection) and the other as the control side (no ethyl chloride spray prior to injection). During the procedure, the participant will be asked to rate the pain associated with the needle injection AND the pain from infiltration of anesthetic from each side of the wound using the visual analog scale (VAS) scoring system (1 = no pain, 10 = most amount of pain possible). The results of the study will help us better understand how to mitigate pain and anxiety for patients requiring MMS.

NCT Number	NCT06920381
Lead Sponsor	University of California, Davis
Conditions	Surgery
Enrollment	77 participants
Start Date	2025-06-01
Primary Completion	2026-03-05 (estimated)
Study Completion	2026-03-05 (estimated)
Updated on ClinicalTrials.gov	2026-07-06