Dermatologists use cryotherapy, or cryosurgery, to treat various skin growths and lesions. This procedure involves applying extreme cold to targeted areas of the skin.
What is Freezing Skin?
Freezing skin involves cryotherapy, a method that uses extremely low temperatures to destroy targeted tissue. The primary agent used for this purpose is liquid nitrogen, which maintains a temperature around -196°C (-320°F).
When applied to the skin, this intense cold causes the water within the cells to freeze rapidly, forming ice crystals. These ice crystals disrupt the cellular structure and membranes, leading to cell death. The freezing and subsequent thawing process also damages the tiny blood vessels supplying the area, further contributing to tissue destruction.
Conditions Treated
Dermatologists commonly use cryotherapy for a variety of skin conditions. Warts, medically known as verrucae, are frequently treated with this method due to its effectiveness in destroying virus-infected cells. Actinic keratoses, which are rough, scaly patches caused by sun damage and considered precancerous, are another common indication for cryotherapy.
Small, benign growths like skin tags and seborrheic keratoses also respond well to freezing. Molluscum contagiosum, a viral skin infection characterized by small, raised bumps, is often treated with cryotherapy to eliminate the lesions. Additionally, certain superficial skin cancers, such as basal cell carcinoma (BCC) and squamous cell carcinoma in situ (SCC in situ), can be treated with cryotherapy, particularly in low-risk cases or for patients who are not suitable candidates for other procedures.
The Procedure and Recovery
During a cryotherapy procedure, liquid nitrogen is applied directly to the skin lesion. This application can occur via a spray device, a cotton swab, or a cryoprobe, depending on the size and nature of the growth. Patients typically experience an immediate sensation of intense cold, followed by stinging or burning, which usually subsides within minutes.
Immediately after the treatment, the treated area often becomes red and swollen. Within several hours, a blister may form, which can be clear or sometimes filled with blood. This blistering is a normal part of the healing process. Over the next few days, the blister may dry up and form a scab, which will naturally fall off within one to three weeks, revealing new skin underneath.
Keeping the treated area clean with gentle soap and water is important during recovery, and applying petroleum jelly can help with healing. Avoid picking at the scab to promote healing and reduce scarring.
Potential Considerations
Following cryotherapy, temporary changes to the treated skin can occur. Changes in skin pigmentation, such as lightening (hypopigmentation) or darkening (hyperpigmentation), are common. While often temporary, these changes can occasionally be permanent, especially in individuals with darker skin tones.
Temporary nerve irritation, leading to numbness or tingling, can occur if a superficial nerve is affected, though normal sensation usually returns. Scarring is a rare but possible outcome, especially if a deeper freeze was necessary.
Monitor the treated site for signs of infection, such as increasing redness, persistent pain, pus, or fever. Contact a healthcare provider if these symptoms develop. If the lesion does not fully resolve after healing, further medical evaluation is advised.