About Cryotherapy

Cryotherapy is used to treat many types of skin lesions including sun damage, harmless skin growths and viral warts. Liquid nitrogen is administered from a spray canister. Cryotherapy does not require a local anaesthetic as pain is usually mild and short lived (although this does vary between individuals and according to the body site being treated). The procedure itself lasts a matter of seconds. The frozen skin becomes white and takes one to two minutes to thaw back to normal skin temperature. It may be repeated up to 3 times at a single site.

Treatment is likely to produce a reaction similar to a burn. The skin may look red, swell, or blister. Redness may not be apparent in people with darker skin. After a few days, a scab will form, and this will take a few weeks to fall off depending on the site (occasionally a little longer, especially on the legs where healing is slow).

Common side effects

• Pain: Cryotherapy is usually well-tolerated but can sometimes be painful if a deep freeze has been necessary. This discomfort can occur both at the time of treatment and for a variable time thereafter. Painkillers (such as paracetamol) taken for the first 24 hours may relieve the discomfort; also taking a painkiller an hour or so prior to the anticipated treatment may reduce the discomfort.
• Swelling and redness: This is a normal immediate response to freezing the skin and usually settles after two to three days. For a short while the treated area may ooze a little watery fluid. Cryotherapy close to the eyes may induce prominent puffiness of the lower eyelids which settles within days.
• Blistering: This is also common, and blisters settle after a few days as the scab forms. Some people blister more easily than others. Occasionally the blisters may become filled with blood; this is harmless. Blisters should only be punctured after seeking medical advice.

Risks

• Scarring (uncommon): Rarely a scar may form. You may be left with a pale mark or a flat white scar, regardless of your skin colour.
• Hypertrophic/Keloid scarring (uncommon): Very rarely a raised scar can form following treatment with cryotherapy which appears as a rounded, hard growth on the skin. These are harmless lesions, more common in darker skinned individuals.
• Pigmentation changes (common): The skin at and around the treatment site may be lighter, darker or redder in colour, especially in darker-skinned people. Pigmentary changes usually improve with time but may be permanent. There may be complete loss of pigmentation leaving a light patch.
• Numbness (uncommon): If a superficial nerve is frozen, it may result in numbness of the area of skin supplied by that nerve. Normal feeling usually returns within a matter of months.
• Recurrence (common): Treatment may fail, or the growth may recur. You might need a repeat treatment or a different treatment.
• Damage to important nerves and blood vessels (very uncommon): Depending upon the site, there is a very small risk of cryothera- py resulting in damage to important nerves or blood vessels that could result in permanent weakness or other serious adverse consequences.
• Damage to nail growth (uncommon): Where cryotherapy is performed close the base of the nail there is a risk of damaging the nail matrix which can result in permanent deformity of the nail.
• Infection (uncommon): There is a small risk of infection. In most cases this can be treated with antibiotics and the site will heal well. Very rarely there can be significant infection that with more significant scarring.
• Hair loss (uncommon): There is a risk of hair loss if a hair-bearing site is treated

Aftercare

Aim to keep the treated areas dry for 24 hours. You can then wash the areas gently and pat dry with a soft towel or tissue. A petroleum jelly (such as Vaseline®) can be applied daily to help the area heal and prevent crusting.

It is important not to pick the scab as this will encourage scarring. A dressing or plaster is not usually necessary but may be advisable if the treated area is likely to be knocked or rubbed by clothing.

In most cases, the treated area will eventually look like normal skin, although scarring and changes in skin colour are possible, and rarely ulceration (broken down areas of skin), particularly on the lower legs.