Warts are common, grainy skin growths caused by the human papillomavirus (HPV), which enters the skin through small cuts or abrasions. While many warts resolve on their own, they are frequently treated with cryotherapy, a method that uses extreme cold to destroy the infected tissue. This procedure involves applying a substance like liquid nitrogen, which instantly freezes the wart and a small margin of surrounding skin. This rapid freezing induces localized cell death, initiating a biological process that ultimately leads to the physical removal of the wart.
The Initial Physical Response
The immediate aftermath of cryotherapy is marked by a rapid inflammatory response in the treated area. Within the first few hours, the site becomes red and slightly swollen, often accompanied by a stinging or burning sensation as the cold wears off. This discomfort is temporary and signifies the body’s reaction to the thermal injury caused by the freezing agent.
Within 24 to 72 hours, a blister typically forms directly beneath the treated wart, which is the most visible sign of success. This fluid-filled pocket develops because the extreme temperature causes the water within the wart’s cells to crystallize, rupturing the cell walls. The resulting blister separates the dead, frozen wart tissue from the healthy underlying skin. Depending on the wart’s size and depth, the blister may contain clear fluid or appear dark, or hemorrhagic, if small blood vessels were frozen and burst.
The Timeline for Wart Shedding
The appearance of the blister marks the start of the tissue separation phase, which progresses over several weeks. The fluid within the blister is eventually reabsorbed by the body, causing the blister to flatten and dry out. This dead tissue then hardens and forms a protective scab or crust over the area.
As the blister dries, the frozen wart tissue underneath often darkens significantly, sometimes turning black, which indicates destroyed cells. This darkened tissue is preparing to detach from the healthy skin. The entire process, from treatment to the complete shedding of the wart, usually takes between one and four weeks.
The timeline depends on factors such as the wart’s original size, its location, and the depth of the initial freeze. Warts on thick-skinned areas, like the soles of the feet, tend to take longer to shed than those on the hands. The successful outcome occurs when the scab, which contains the dead wart, lifts away naturally, revealing new, pink, healthy skin underneath.
Managing the Healing Process and Recurrence
Proper care of the treated area minimizes discomfort and promotes optimal healing during the recovery period. If a blister forms, it is best to leave it intact, as the overlying skin provides a sterile barrier against infection. Should the blister rupture, the area must be kept clean and covered with a simple bandage to protect the open skin.
Over-the-counter pain relievers can manage soreness that persists for the first few days following the procedure. Avoid picking at the scab or crust that forms, as premature removal increases the risk of scarring and interrupts the healing process. Signs of infection, such as increasing redness, warmth, or pus, should prompt a consultation with a healthcare professional.
Cryotherapy often requires multiple sessions because the first application may not kill all the HPV-infected cells, leading to recurrence. The virus can persist in the deeper layers of the skin even after the visible growth is gone. To fully eradicate the wart, follow-up treatments are frequently scheduled, typically spaced one to three weeks apart, allowing the skin to heal sufficiently between applications.