Cryotherapy -CryoProbe

Cryotherapy refers to a treatment in which surface skin lesions are frozen. Liquid nitrogen is used more often than carbon dioxide snow or other cryogens.

Skin lesions treated with cryotherapy
The most common lesions treated with cryotherapy are:
· Solar keratoses
· Skin Tags
· Seborrhoeic keratoses (senile warts)
Freezing may be the most suitable way of getting rid of many different kinds of surface skin lesion. It is relatively inexpensive, safe, and reliable.

The treatment

Cryotherapy using liquid nitrogen (temperature -196C) involves the use of a cryoprobe.. The nitrogen is applied to the skin lesion for a few seconds, 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' and is usually reserved for skin cancers or resistant viral warts.

Cryotherapy stings and may be painful, at the time and for a variable period afterwards. There may be immediate swelling and redness. This may be reduced by applying a topical steroid on a single occasion straight after freezing. Aspirin orally may also reduce the inflammation and discomfort.

Looking after the treatment area

The treated area is likely to blister within a few hours. Sometimes the blister is clear and sometimes it is red or purple because of bleeding (this is harmless). Treatment near the eye may result in a puffy eyelid, especially the following morning, but the swelling settles within a few days. Within a few days a scab forms and the blister gradually dries up.

Usually no special attention is needed during the healing phase. The treated area may be gently washed once or twice daily, and should be kept clean. A dressing is optional, but is advisable if the affected area is subject to trauma or clothes rub on it.

When the blister dries to a scab, apply petroleum jelly (Vaseline) and avoid picking at it. The scab peels off after 5-10 days on the face and 3 weeks on the hand. A sore or scab may persist as long as 3 months on the lower leg because healing in this site is often slow.

Secondary infection is uncommon. When it occurs it may cause increased pain, swelling, thick yellow blister fluid, a purulent discharge and/or redness around the treated area. Consult your doctor if you are concerned: topical antiseptics and/or oral antibiotics may be necessary.

Final results

After a standard freeze of a solar keratosis, seborrhoeic keratosis or skin tag, the skin may appear entirely normal without any sign of the original skin lesion.

However, cryotherapy may result in a white mark (hypopigmentation) or a scar, particularly when freezing has been deep or prolonged, as is required for a cancerous lesion. A white mark may sometimes follow a light freeze. The white mark may be quite noticeable especially in those with darker complexions. Although the appearance often improves with time, the color change can be permanent.

Skin lesions may fail to clear or may recur at a later date, necessitating further cryotherapy, surgery or other treatment.

A hard freeze to the skin overlying a superficial sensory nerve, such as treatment to a viral wart on the side of a finger, can cause numbness of the skin area that the nerve supplies. The feeling nearly always returns to normal within a few weeks or months.