How is cryotherapy (cryo) performed to treat skin conditions?

From the Guidelines

Cryotherapy for skin conditions is performed by applying liquid nitrogen with a cotton-tipped applicator for 15–20 seconds, until 1–2 mm of the circumferential skin around the lesion appears frozen, then thawing for 20–60 seconds, and repeating the freeze step, with the entire process repeated at 3-week intervals until healing occurs, as recommended by the most recent and highest quality study 1. The procedure involves using liquid nitrogen (-196°C) applied directly to the affected area, causing controlled tissue destruction.

• The treatment works through rapid freezing that creates ice crystals within cells, disrupting cell membranes and causing cell death.
• Most conditions require 1-3 treatment sessions spaced 2-4 weeks apart.
• After treatment, patients may experience redness, swelling, blistering, and mild pain that typically resolves within 1-2 weeks.
• The treated area will form a crust that eventually falls off, revealing new skin underneath.
• Cryotherapy is effective for treating various skin conditions, including warts, seborrheic keratoses, actinic keratoses, and some superficial skin cancers, with the advantage of being quick, relatively painless, and requiring no anesthesia, as supported by studies 1. However, the most recent and highest quality study 1 provides the most up-to-date guidance on the use of cryotherapy for skin conditions, and its recommendations should be prioritized in clinical practice. It's also important to note that the success of cryotherapy is highly dependent on the skill of the operator and complete, careful application, as emphasized in the study 1.

From the Research

Cryotherapy Procedure

Cryotherapy, also known as cryo, is a common technique used to treat various skin conditions, including superficial skin lesions and warts. The procedure involves the application of extreme cold to destroy abnormal or damaged cells.

Methods of Cryotherapy

There are several methods of cryotherapy, including:

• Liquid nitrogen cryotherapy: This is the most widely used method, which involves the application of liquid nitrogen to the affected area using a cotton wool bud or a cryo-spray 2, 3.
• Dimethyl ether-propane spray cryotherapy: This method uses a spray to apply the cryogenic agent to the affected area 4.
• Open spray technique: This method uses a handheld spray device, also known as the "cryo gun", to apply the cryogenic agent to the affected area 5.

Application and Freeze-Thaw Cycles

The application of cryotherapy typically involves the following steps:

• The affected area is cleaned and prepared for treatment.
• The cryogenic agent is applied to the affected area using the chosen method.
• The area is frozen for a specified period, usually until an ice ball forms and includes a margin of 2 mm around the lesion 2.
• The area is then allowed to thaw, and the process may be repeated for a specified number of freeze-thaw cycles.
• The optimum cellular degradation is achieved with 5-min freeze-thaw cryotherapy cycles 6.

Treatment Outcomes

The effectiveness of cryotherapy in treating skin conditions varies depending on the type of condition, the method used, and the individual patient. Studies have shown that cryotherapy can be an effective treatment for common warts, with cure rates ranging from 39% to 49% 2, 3. However, the effectiveness of cryotherapy for plantar warts is less clear, with some studies showing no significant difference in cure rates between cryotherapy and other treatments 3.