Warts are infectious, non-cancerous tumors caused by the human papillomavirus or HPV. There are several different types of wart, each caused by a different type of HPV.
Most warts are painless and harmless and go away on their own after a few months or possibly years. But depending on their location, size, and type, warts can cause more serious symptoms that warrant treatment.
Cryosurgery, or the use of very cold temperatures to freeze off abnormal cells and tissues, is one of the most commonly used treatments to remove all types of warts.
Fast facts on freezing warts:
- Typically, cryosurgery is performed by a doctor or dermatologist in their office.
- In a clinical setting, liquid nitrogen doses are used during cryosurgery.
- The average dose temperature is minus 196 °C.
- Temperatures of at least minus 40 °C or lower are considered necessary to freeze warts.
Symptoms and problems that might necessitate treatment include:
- discomfort or pain
- anxiety and depression
- warts becoming large
- disability, such as being unable to walk easily
- exposure of the wart to friction or pressure
- warts that last for more than a few years
- warts on the soles of the feet called plantar warts
A doctor usually begins by paring the wart, using a scalpel. This process scrapes away dead skin cells to increase the amount of infected surface to be exposed to the liquid nitrogen.
In some cases, a doctor may instruct an individual to pare down the wart at home the night before the procedure, or apply salicylic acid gels, creams, and bandages, nightly for 1 to 2 weeks before cryosurgery.
During most cryosurgeries, a tool called a cryostat gun, probe, cotton ball, or dipstick is used to deliver a dose of liquid nitrogen to the wart.
Every doctor will have their preferences and methods. However, most cryosurgeries involve at least one, 10-second freezing session. Each session should last no longer than 30 seconds.
Liquid nitrogen-based cryosurgery can be safely used on all kinds of warts, as long as additional health conditions do not prohibit the procedure.
Most warts, except very small ones or those on the hands, require more than one treatment. Larger and plantar warts often need two freezing sessions per treatment.
Overall, the removal of warts usually requires between 1 to 6 treatments in total, performed once every 2 to 3 weeks for several months.
Though many doctors and dermatologists use cryosurgery to treat warts, there is limited research to support the use of the procedure over concentrated salicylic acid treatment.
Given its wide and often successful use, researchers are now beginning to produce evidence that cryotherapy may be the most effective treatment for certain kinds of warts.
What do the studies say?
A retrospective study from 2015 concluded that cryosurgery is effective in removing common warts in some
When considering the success rate of cryotherapy, it is important to understand that the procedure does not cure the underlying viral infection.
Currently, there is no antiviral medication known to treat the HPV virus. This means that warts can regrow, although, often, once they are removed, the body's immune system can destroy any remaining infected cells to get rid of the virus.
Large warts and plantar warts on the soles of the feet tend to be both the hardest to treat and most likely to return after cryosurgery. By some estimates, plantar warts have a return rate of more than 50 percent after cryosurgery.
People are not able to perform liquid nitrogen-based therapies at home. Several over-the-counter products, however, claim to freeze warts, using a mixture of dimethyl ether, propane, and sometimes isobutane.
They are not considered as good as cryosurgery because they do not reach such cold temperatures. Nevertheless, Dr. Scholl's Freeze Away Wart Remover has been shown to maintain a temperature of minus 42 °C at its applicator tip.
Some studies say that over-the-counter wart freezing products can freeze tissues to minus 94 °C.
Over-the-counter wart freezing products:
- CompoundW Freeze off
- Histofreezer Wart Removal System
- Wartner Wart Remover System
- Dr. Scholl's Freeze Away Wart Remover
Other over-the-counter wart removal products contain the same acids as doctors use to remove warts. These products can be gels, patches, pads, and strips, although the acid is at much lower doses and concentrations than a doctor would use. They can be purchased online.
In most cases, over-the-counter products are only effective in removing small, common warts from the hands and fingers. For larger or more complicated growths, such as plantar warts, home remedies will normally only reduce the size or appearance of the wart temporarily.
Alternative remedies, such as applying duct tape to the area for several weeks, are commonly used but have little scientific backing.
Most people experience minor pain during cryosurgery and a burning sensation when the skin thaws afterward.
During and immediately after the procedure, the treatment site may become red and swollen. It may also be sore for a few days after the surgery.
A lot of people develop a blister or fluid-filled sac within 24 hours where the wart was removed. Most blisters caused by cryosurgery tend to go away on their own in 2 or 3 days.
During the entire recovery period, typically a week or so, areas treated with cryotherapy should be kept clean, dry, and free from friction or pressure.
The risks associated with cryosurgery depend on the type, size, and location of the wart being treated.
Usually, plantar warts, large warts, and those in areas that experience a lot of pressure or friction tend to cause the most pain and risks of complication, such as scarring or tissue damage.
Potential side effects of cryosurgery include:
- skin irritation
- alopecia or hair loss
- hypopigmentation or loss of skin pigment
- blood blisters
- tissue damage
- bleeding, especially during paring
- nerve damage, although rare
- altered skin sensation
Infection is one of the most serious, complications associated with cryosurgery.
Common signs of infection include:
- intense, throbbing pain
- pus or white fluid
- yellow or brown fluid
- bad-smelling wounds
- wounds that do not heal after a few days of care and good hygiene
Without treatment, an infection can lead to many side effects, including coma and death in extreme cases. It is important to seek medical treatment if an infection is suspected.