Is topical ethyl chloride a numbing medicine?

Topical Ethyl Chloride as a Numbing Medicine

Yes, ethyl chloride spray is a topical numbing medicine that works through rapid cooling of the skin, but it has contradictory evidence regarding its effectiveness and should not be considered as a sole method for analgesia in dermatologic procedures. 1

Mechanism of Action and Uses

• Ethyl chloride works as a cryoanalgesic - it rapidly evaporates upon contact with skin, causing cooling that temporarily numbs the area
• It is primarily used to:
  • Reduce pain before injections or minor procedures
  • Decrease discomfort during needle insertion
  • Provide brief, superficial anesthesia

Effectiveness in Clinical Practice

The evidence regarding ethyl chloride's effectiveness is mixed:

• Dermatologic procedures: Guidelines from the American Academy of Dermatology indicate contradictory evidence regarding ethyl chloride's pain reduction potential 1
• Hand injections: A 2017 study found that ethyl chloride imparted no benefit for routine hand injections compared to no topical spray 2
• Pediatric venipuncture: Some evidence suggests it may be as effective as topical anesthetics in preventing distress during venipuncture in children 3
• Dental procedures: A 2023 study found ethyl chloride more effective than topical lidocaine in alleviating needle injection pain before dental anesthesia 4

Safety Considerations

When using ethyl chloride, be aware of these important safety concerns:

• Flammability: Ethyl chloride is highly flammable - there is a reported case of unwanted ignition with laser therapy causing a first-degree burn 1, 5
• Sterility: Although labeled as nonsterile, research suggests application of ethyl chloride after proper skin preparation does not significantly alter skin sterility 6
• Toxicity risks: Excessive use or inhalation can lead to neurotoxicity with cerebellar symptoms including ataxia and coordination problems 7
• Frostbite potential: Prolonged application can cause tissue damage due to excessive cooling 2

Clinical Application Guidelines

For optimal use when ethyl chloride is selected:

1. Properly prepare the skin with antiseptic first
2. Apply ethyl chloride briefly (1-2 seconds) from 15-30 cm distance
3. Allow complete evaporation before any invasive procedure
4. Never use with energy-based devices due to flammability risk
5. Avoid prolonged application to prevent frostbite

Alternative Approaches

Guidelines suggest these alternatives may be more effective for pain management:

• Slow rate of infiltration of local anesthetics
• Vibration of the skin during injection
• Use of warm anesthetic solutions (40°C)
• Cold air skin cooling for certain procedures 1

Ethyl chloride should be viewed as one option in the pain management toolkit rather than a definitive solution, particularly given its contradictory evidence base and safety considerations.