Liquid nitrogen treatment or cryotherapy is a routine procedure for the removal of benign skin growths as well as some precancerous conditions – chicken pox, warts, keratoses, actinic keratoses and others. For this purpose, the liquefied nitrogen is placed in a special device (cryojet) consisting of a tank, a trigger and a nozzle. When the trigger is pulled, it comes out under pressure and falls on the target area. The availability of nozzles of different sizes and shapes allows for extreme precision of the procedure. The boiling point of the liquefied nitrogen is approximately minus 195.8 °C, which results in instant tissue freezing. Since water expands on freezing, and most of the cells are water, performing several freeze cycles destroys the cellular components, and with it the treated tissue perishes. The advantages with skin are that precise control allows the trauma to be confined to the relevant entity, and the underlying healthy dermis ensures that the area heals completely with minimal risk of scarring.

The formation is sprayed several times in succession, waiting for thawing and refreezing. The duration for each entity is different and is determined by both its structure and its size. When spraying, the area turns white, and after thawing the skin is red. With the initial spraying, the sensations are of cold and tingling, after which burning and pain appear. The nature of pain after cryotherapy is inconsistent, dull and throbbing, comparable to that after a burn.

The procedure is contraindicated in people suffering from cryoglobulinemia, cold allergy, and peripheral vascular disorders such as Raynaud’s disease, diabetic vasculopathy, and others. After the procedure, the main side effect is pain, which lasts from several hours to days depending on the size of the treated area and localization. In most cases after treatment, the area turns black, then falls off after a period of one to several weeks. In rarer cases, after the procedure, a blister forms on the affected area as if from a burn. The risk of hypo- or hyperpigmentation and atrophic scars after cryotherapy is minimal.

Once a cure is reached, the effect of the procedure is definitive.

The number of treatments varies greatly according to the type of growths and the individual body’s response. Small flat warts on the hands have the highest cure rate after one treatment, while chicken pox on the feet usually needs an average of 3 visits. With several consecutive procedures, the interval between them is 10 to 14 days.