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Cryotherapy is a technique that uses an extremely cold liquid or instrument to freeze and destroy abnormal skin cells that require removal. The technique has been in use since the turn of the century, but modern techniques have made it widely available to dermatologists and primary care doctors. The technique is also called cryosurgery.
Cryotherapy can be employed to destroy a variety of benign skin growths, such as warts, pre-cancerous lesions (such as actinic keratoses), and malignant lesions (such as basal cell and squamous cell cancers). The goal of cryotherapy is to freeze and destroy targeted skin growths while preserving the surrounding skin from injury.
Cryotherapy is not recommended for certain areas of the body because of the danger of destruction of tissue or unacceptable scarring. These areas include: skin that overlies nerves, the corners of the eyes, the fold of skin between the nose and lip, the skin surrounding the nostrils, and the border between the lips and the rest of the face. Lesions that are suspected or known to be malignant melanoma should not be treated with cryotherapy, but should instead be removed surgically. Similarly, basal cell or squamous cell carcinomas that have reappeared at the site of a previously treated tumor should also be removed surgically. If it remains unclear whether a growth is benign or malignant, a sample of tissue should be removed for analysis (biopsy) by a pathologist before any attempts to destroy the lesion with cryotherapy. Care should be taken in people with diabetes or certain circulation problems when cryotherapy is considered for growths located on their lower legs, ankles, and feet. In these patients, healing can be poor and the risk of infection can be higher than for other patients.
There are three main techniques to performing cryotherapy. In the simplest technique, usually reserved for warts and other benign skin growths, the physician will dip a cotton swab or other applicator into a cup containing a "cryogen," such as liquid nitrogen, and apply it directly to the skin growth to freeze it. At a temperature of −320°F (−196°C), liquid nitrogen is the coldest cryogen available. The goal is to freeze the skin growth as quickly as possible, and then let it thaw slowly to cause maximum destruction of the skin cells. A second application may be necessary depending on the size of the growth. In another cryotherapy technique, a device is used to direct a small spray of liquid nitrogen or other cryogen directly onto the skin growth. Freezing may last from five to 20 seconds, depending on the size of the lesion. A second freeze-thaw cycle may be required. Sometimes, the physician will insert a small needle connected to a thermometer into the lesion to make certain the lesion is cooled to a low enough temperature to guarantee maximum destruction. In a third option, liquid nitrogen or another cryogen is circulated through a probe to cool it to low temperatures. The probe is then brought into direct contact with the skin lesion to freeze it. The freeze time can take two to three times longer than with the spray technique.
Extensive preparation prior to cryotherapy is not required. The area to be treated should be clean and dry, but sterile preparation is not necessary. Patients should know that they will experience some pain at the time of the freezing, but local anesthesia is usually not required. The physician may want to reduce the size of certain growths, such as warts, prior to the cryotherapy procedure, and may have patients apply salicylic acid preparations to the growth over several weeks. Sometimes, the physician will pare away some of the tissue using a device called a curette or a scalpel.
Redness, swelling, and the formation of a blister at the site of cryotherapy are all expected results of the treatment. A gauze dressing is applied and patients should wash the site three or four times daily while fluid continues to ooze from the wound, usually for five to 14 days. A dry crust then forms that falls off by itself. Wounds on the head and neck may take four to six weeks to heal, but those on the body, arms, and legs can take longer. Some patients experience pain at the site following the treatment. This can usually be eased with acetaminophen (Tylenol), though in some cases a stronger pain reliever may be required.
Cryotherapy poses little risk and can be well-tolerated by elderly and other patients who are not good candidates for other surgical procedures. As with other surgical procedures, there is some risk of scarring, infection, and damage to underlying skin and tissue. These risks are generally minimal in the hands of experienced users of cryotherapy.
Actinic keratosis — A crusty, scaly pre-cancerous skin lesion caused by damage from the sun. Frequently treated with cryotherapy.
Basal cell cancer — The most common form of skin cancer; it usually appears as one or several nodules having a central depression. It rarely spreads (metastisizes), but is locally invasive.
Cryogen — A substance with a very low boiling point, such as liquid nitrogen, used in cryotherapy treatment.
Melanoma — The most dangerous form of skin cancer. It should not be treated with cryotherapy, but should be removed surgically instead.
Squamous cell cancer — A form of skin cancer that usually originates in sun-damaged areas or pre-existing lesions; at first local and superficial, it may later spread to other areas of the body.
Some redness, swelling, blistering and oozing of fluid are all common results of cryotherapy. Healing time can vary by the site treated and the cryotherapy technique used. When cryogen is applied directly to the growth, healing may occur in three weeks. Growths treated on the head and neck with the spray technique may take four to six weeks to heal; growths treated on other areas of the body may take considerably longer. Cryotherapy boasts high success rates in permanently removing skin growths; even for malignant lesions such as squamous cell and basal cell cancers, studies have shown a cure rate of up to 98%. For certain types of growths, such as some forms of warts, repeat treatments over several weeks are necessary to prevent the growth's return.
Although cryotherapy is a relatively low risk procedure, some side effects may occur as a result of the treatment. They include:
- Infection. Though uncommon, infection is more likely on the lower legs where healing can take several months.
- Pigmentary changes. Both hypopigmentation (lightening of the skin) and hyperpigmentation (darkening of the skin) are possible after cryotherapy. Both generally last a few months, but can be longer lasting.
- Nerve damage. Though rare, damage to nerves is possible, particularly in areas where they lie closer to the surface of the skin, such as the fingers, the wrist, and the area behind the ear. Reports suggest this will disappear within several months.
American Academy of Dermatology. 930 N. Meacham Road, P.O. Box 4014, Schaumburg, IL 60168-4014. (847) 330-0230. Fax: (847) 330-0050. http://www.aad.org.
American Society for Dermatologic Surgery. 930 N. Meacham Road, PO Box 4014, Schaumburg, IL 60168-4014. (847) 330-9830. http://www.asds-net.org.
the therapeutic use of cold; see also hypothermia.
The use of cold in the treatment of disease.
The local or general use of low temperatures in medical therapy. Also called crymotherapy.
cold therapyA general term for the use of ice or cold compresses for therapeutic purposes; locally applied ice increases the circulation and relieves pain, and is of use in acute trauma. Practitioners of alternative therapies may advocate alternating ice and heat, as it is believed to “flush” a region with fresh blood.
cryotherapyMainstream medicine The use of cold to ↓ discomfort, limit progression of edema or interrupt muscle spasms, which acts as a counterirritant Ophthalmology A safe, effective therapy for retinopathy of prematurity Cons ↓ visual acuity and smaller visual field
cold ther·a·py(kōld thār'ă-pē)
A type of care in which ice or cold water is applied to a body part.
cryotherapy(krī″ō-ther′ă-pē) [ cryo- + therapy]
1. The application of cold to a body part to decrease tissue temperature, and thereby to decrease cellular metabolism, improve cellular survival, decrease inflammation, decrease pain and muscle spasm, and promote vasoconstriction. See: illustrationtable
|Acute injury or inflammation||Anesthetic skin|
|Acute or chronic pain||Cold allergy/cold-induced urticaria|
|Acute or chronic muscle spasm||Cold-induced myocardial ischemia (or other unstable heart or lung disease)|
|Neuralgia||Diabetes mellitus (when complicated by vascular disease or sensory loss)|
|Postsurgical pain and edema||Peripheral vascular disease|
|Use prior to rehabilitation exercises||Raynaud's phenomenon|
|Small, superficial, first-degree burns||Systemic lupus erythematosus|
|Spasticity accompanying central nervous system disorders||Uncovered open wounds|
cryotherapyThe use of low temperatures in medical treatment. Temperatures of about -20 C or below are useful in surgery, especially for destroying unwanted tissue such as warts, ACTINIC KERATOSIS and skin nodules (dermatofibromas). See also CRYOSURGERY.
Method of treating a disease by the use of cold as a destructive medium. It may be used in the treatment of retinal detachment and breaks, conjunctival melanomas, lid tumours, uveitis, distichiasis and trichiasis.