• Incomplete removal or recurrence of a treated skin lesion
• Increased redness of the treated area, but usually this resolves with time
• A lighter coloured patch in the treated area which can be permanent
• Delayed healing may occur, especially after treatment on the lower legs
• On hairy areas of skin, treatment usually leads to a permanent loss of hair growth in the treated area
• Sensation may very rarely be affected due to damage to nerve endings or nerve branches, though this often improves with time
• Depressed or raised scars can rarely occur

• Some stinging pain during freezing and thawing
• Pain-killer medicine may be needed if pain occur afterwards
• Some redness and swelling, and a blister may form

In primary care, cryotherapy is usually only used to treat benign conditions, because there may be difficulties in accurately diagnosing, ensuring adequate treatment, and following-up the pre-malignant or malignant skin diseases.

Other common uses of cryotherapy include:

• Removal of common viral warts
• Verruca infections on the soles of the feet
• Molluscum Contagiosum
• Skin tags
• Seborrheic warts
• Plane warts

Cryotherapy for a wart or verruca may need 3 - 4 treatment sessions, at 2 - 3 weekly intervals.

The two most common methods to apply liquid nitrogen to the skin are using a hand-held spray or cotton-buds. For the spray method, a shield may be used to protect the surrounding normal skin from unnecessary freezing. The cotton-bud method involves repeatedly dipping the bud into a small pot of liquid nitrogen and pressing it onto the skin lesion.

The abnormal area of skin needs to be frozen to a sufficiently low temperature for long enough; as well as being frozen widely and deeply enough. The aim is to cause enough freezing to ensure sufficient cells are killed, whilst minimising any damage to the deeper or surrounding normal skin. Then we rely on the body’s ability to heal its self, in order to return the treated area to as normal an appearance as possible after the skin problem has been removed.