We're keen to explain some of the strategies we use to help stop cancers developing. Our Skin tip # 5 topic is 'cryotherapy' or freezing skin.
Why freeze skin?
Liquid nitrogen is used to freeze precancerous spots, warts, skin tags and often the pigmented blemishes often called 'liver spots'.
People often choose to freeze these when they are small. If left unchecked, they can become warty (senile warts) and bothersome over time. These can also complicate skin checks because at certain stages of their development they can mimic melanoma at which point surgical intervention may be required so they can be checked by the lab to confirm they are OK.
Freezing precancerous 'actinic' spots helps to stop people developing squamous cell carcinoma. The 'Actinic kerratosis' is like as small, firm, silvery crust that grows on sun damaged skin. They are extremely common on noses of Kiwis over 50 years old and if you pick them off they will always come back in the same spot.
They can usually be 'cured' by freezing them.
Left untreated some of them will turn into cancer.
Its sensible and easier to treat them in their early stages.
Dry ice or liquid nitrogen?
Dry Ice = frozen carbon dioxide. It is solid. In the old days we made a freezing slurry of dry ice and acetone and applied it to spots with a cotton bud. It was time consuming. TEMP = -78.5 C
Liquid nitrogen = frozen air. Liquid nitrogen is a liquid that evaporates when it comes into contact with normal air. In expert hands it is extremely safe. It is a very chilly = -195 .8C
The difference between using dry ice and liquid nitrogen is that liquid nitrogen is colder so more effective. It is also easier to control when its being applied. With liquid nitrogen, many spots can be treated efficiently in a short time, and it is also safe to treat around the eyes.
What happens when a spot is 'frozen'?
There is a slight sting for a few minutes.
The surface of the skin has been given frost bite and it dies and is replaced by new, healthy skin.
Over 1-2 weeks a a scab forms and then drops off.
Underneath you have new skin. This new skin has to be protected from the sun until it gets the normal light 'tan' that protects skin from sunburn.
Sometimes the spots blister; If you get a blister leave the skin over the blister ... it's like the world's best band aid because it holds in the moisture needed for healing. If the blister pops you can use a plaster to lock on the protective skin so it doesn't fall off.
If you have had a spot frozen its fine to ignore it. It's like a tiny burn and your body knows exactly how to heal it. That keeps things simple at home.
Occasionally people get a bit of extra pigment where a spot has been frozen. This usually disappears in 6 -18 months.
Its a good idea to hold off getting spots frozen on your face for at least a month before photographs, weddings or other important events where you prefer not to look spotty.
As the skin heals it will develop a small scab. Its tempting to remove these but pulling them off can scar. If the healing skin is bothersome its preferable to keep the scab soft with something like a moisturiser or vaseline.
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