Why Does Alcohol Burn on a Cut or Wound?

Why Alcohol Stings and Feels Hot

overhead shot of first aid kit
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If you've ever applied alcohol to a cut or other wound, you know it stings and burns. It doesn't matter which type of alcohol you use — ethanol, isopropyl, and rubbing alcohol all produce the effect. The alcohol doesn't physically burn you, but you feel the sensation because the chemical activates the same nerve receptors in your skin that let you know boiling water or a flame are hot.

Special cells called VR1 receptors fire neurochemical signals to your brain when they are exposed to heat.

When the receptors are exposed to alcohol, like when you pour alcohol-based disinfectant onto an open cut, the alcohol molecule lowers the temperature threshold required to send this signal. Scientists studying the interaction between ethanol and VR1 receptors have determined the receptors are triggered 10 degrees cooler than normal. Other types of alcohol appear to act similarly.

Although it isn't known for certain, it's possible the heat generated by cells as part of the inflammation response acts as the source of the burning sensation. Some people believe applying alcohol to skin before damaging it (e.g., for a vaccination) cools the skin enough to prevent or lessen the burning sensation. Interestingly, even chilled alcohol applied to a cut will sting.

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