The literal meaning of cryotherapy is - 'treatment using low temperature’ and points to a procedure wherein skin lesions are destroyed by the process of freezing.
Cryotherapy may be used to treat benign, superficial skin lesions, but it is most commonly used to remove conditions like viral warts, actinic keratoses and seborrheic keratosis. Occasionally (after discussing the pros and cons) cryotherapy may also be recommended to treat superficial low-grade skin cancers like Bowen’s disease and basal cell carcinomas.
Liquid nitrogen, the liquid form of gaseous nitrogen, which covers 78 percent of the air we breathe, is the most common agent used for cryotherapy. It is commonly used because liquid nitrogen is extremely cold with a low boiling point of minus 196 degrees Celsius. Typically liquid nitrogen is stored and transported in special flasks.
The procedure typically involves one of three main techniques. However, the aim of all three techniques is to first freeze the area and then gradually let it thaw to ensure maximum destruction of the unwanted growth.
The simplest technique involves using a simple equipment - a cotton swab. The cotton swab is dipped into a bowl of liquid nitrogen and applied directly to the lesion. Depending on the size of the lesion, a second application may be required.
Another technique involves spraying liquid nitrogen onto the lesion. Sometimes the temperature is monitored by inserting a needle, attached to a thermometer. This is done to make sure the growth is cooled down to a temperature which can ensure maximum destruction.
A third technique involves circulating liquid nitrogen through a probe. The probe is directly brought into contact with the skin lesion and frozen.
After the procedure, scabs may form which usually drop off in a week or two. Keep the area dry and do not scratch pick on or attempt to peel the scab.
More than one session may be required, depending on the type, size and depth of the lesion. A burning sensation may follow the procedures, but they usually wane off within a few minutes.
Common side effects of liquid nitrogen cryotherapy include:
Other side-effects include numbness, recurrence of the skin growth and rarely, infection and scarring.
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