How does cryotherapy work?

Cryogens used to freeze skin lesions include:

• Liquid nitrogen (the most common method used by doctors, temperature –196°C)
• Carbon dioxide snow (more commonly used 20 years ago, –78.5°C)
• Dimethyl ether and propane or DMEP (available over the counter, –57°C).

Skin lesions treated with cryotherapy

Freezing may be the most effective treatment for a variety of skin lesions on the surface. It is reasonably priced, safe, and dependable. It is critical, however, that the skin lesion be accurately diagnosed. Melanoma or any undetected pigmented lesion that could be melanoma should not be treated with it.

Cryotherapy stings and can be uncomfortable at the time of application and for some time following.

Treatment Options

Liquid nitrogen

A cryospray, cryoprobe, or cotton-tipped applicator are used in liquid nitrogen cryotherapy. Depending on the type of lesion, the diameter and depth of freeze, nitrogen is given to the skin lesion for a few seconds or longer. In some circumstances, after the thawing process is complete, the treatment is repeated. This is referred to as a “double freeze-thaw.”

Carbon dioxide snow

Making a cylinder of frozen carbon dioxide snow or a slush mixed with acetone is the first step in carbon dioxide cryotherapy. After it is made, it is directly administered to the skin lesion.

DMEP

DMEP is available in an aerosol can that can be purchased over the counter. It is applied to the skin lesion with a foam applicator for 10 to 40 seconds, depending on the size and location of the lesion.

Looking after the treatment area

Applying a topical steroid on a single occasion after freezing can help to minimize immediate edema and redness. Oral aspirin can also help with inflammation and pain.

Depending on the depth and length of the freeze, the treated region is likely to blister within a few hours. Because of bleeding, the blister may contain clear fluid at times and be red or purple at other times (this is harmless). Treatment near the eye may cause a puffy eyelid the next morning, but the swelling will subside within a few days. A scab forms after a few days, and the blister progressively heals.

During the healing process, no particular treatment is usually required. The treated area should be cleaned lightly once or twice a day and kept clean. A dressing is not required, although it is recommended if the affected area has been traumatized or if clothing rubs against it.

Apply petroleum jelly to the blister when it turns into a scab and don’t pick at it. The scab on the face peels off after 5–10 days, and the scab on the hand peels off after 3 weeks. Because recovery in this area is generally delayed, a sore or scab on the lower leg can last up to three months.

Results of cryotherapy

The skin may appear completely normal after a typical freezing of actinic keratosis, seborrheic keratosis, or viral warts, with no trace of the initial skin lesion. This may necessitate numerous treatments.

Complications of cryotherapy

The most serious issue is subsequent wound infection, which is rare. Increased pain, swelling, thick yellow blister fluid, purulent discharge, and/or redness around the treated region are all signs of infection. If you’re worried, talk to your doctor; topical antiseptics and/or oral antibiotics may be required.

Other undesirable effects may include:

• Delayed healing and ulceration
• Local nerve damage (usually temporary)
• Permanent hypopigmentation or scar
• Persistent or recurrent skin lesions, necessitating further cryotherapy, surgery or other treatment.