Liquid nitrogen is extremely cold. It will freeze any living tissue it comes into contact with. Applying small amounts of liquid nitrogen to various skin problems is now a standard treatment. The medical term for this treatment is cryotherapy.
What can liquid nitrogen treat?
Warts and verrucas, skin tags, small fleshy growths and similar small 'lumps and bumps' on the skin are ideal for liquid nitrogen treatment.
Is liquid nitrogen treatment painful?
Applications usually last about 10-30 seconds. Try holding a cube of ice against your skin for 10-30 seconds. It is uncomfortable but usually not too painful. Liquid nitrogen applied to skin is similar but colder and most people find the discomfort quite bearable.
What can I expect from liquid nitrogen treatment?
After a liquid nitrogen treatment, the lump, wart or whatever is being treated will gradually discolour and fall off. The surrounding skin will sometimes become red and swollen and be sore for a day or so. It is similar to a mild burn. Occasionally a blister (sometimes a 'blood blister') forms. If this happens, it is best to pop it with a clean pin and apply a plaster. New skin quickly forms and any scab or blister will soon disappear. The cosmetic result is usually good.
Does liquid nitrogen treatment always work?
Usually it does. However, sometimes thicker warts or verrucas need two or more sessions of liquid nitrogen treatment over a period of a few weeks to get to the root. It may work but is no more effective than over-the-counter treatment with salicylic acid.
Further reading and references
Cockayne S, Hewitt C, Hicks K, et al; Cryotherapy versus salicylic acid for the treatment of plantar warts (verrucae): a randomised controlled trial. BMJ. 2011 Jun 7342:d3271. doi: 10.1136/bmj.d3271.
Kwok CS, Gibbs S, Bennett C, et al; Topical treatments for cutaneous warts. Cochrane Database Syst Rev. 2012 Sep 129:CD001781. doi: 10.1002/14651858.CD001781.pub3.
Bruggink SC, Gussekloo J, Berger MY, et al; Cryotherapy with liquid nitrogen versus topical salicylic acid application for CMAJ. 2010 Oct 19182(15):1624-30. Epub 2010 Sep 13.