Cryotherapy is a minimally invasive procedure that uses an extremely cold liquid or instrument to freeze and destroy abnormal tissue that requires elimination. It is also referred to as cryosurgery or cryoablation.
The cryogen used by specialist dermatologists or skin doctors to freeze skin lesions is liquid nitrogen (the most common method used by doctors). Liquid nitrogen has a temperature of −196 °C.
The nitrogen is applied to the skin lesion for a few seconds using a cryospray, depending on the desired diameter and depth of freeze. The treatment is repeated in some cases, once thawing has completed. This is known as a “double freeze–thaw”.
Lesions that are commonly treated by cryotherapy include actinic keratosis (a precancerous skin lesion caused by sun damage), viral warts, molluscum contagiosum in adults, and seborrheic keratosis (or senile warts). Other non-cancerous lesions that can be treated include skin tags, keloids and xanthelasmas (cholesterol spots).
Specialist dermatologists sometimes freeze small skin cancers such as superficial basal cell carcinomas and in-situ squamous cell carcinomas (intraepidermal carcinoma, Bowen disease), but this is not always successful, so careful follow-up is necessary.
Freezing may be the most suitable way of getting rid of many different kinds of surface skin lesions. It is relatively inexpensive, safe, and reliable. However, it is important that the skin lesion has been properly diagnosed. It should not be used to treat melanoma or any undiagnosed pigmented lesion that could be melanoma.
Cryotherapy is hardly ever used in young children. It’s used with caution in dark-skinned patients as it may lead to hypopigmentation. Dermatologists also prefer not to use it on the corners of the eyes, the fold of skin between the nose and lip, the skin surrounding the nostrils, and skin overlying nerves.