**4.8 Cryotherapy**

Cryotherapy induces cold thermal injury in the lesion. Cryotherapy may have an effect on wart clearance either by simple necrotic destruction of HPV-infected keratinocytes or possibly by inducing local inflammation conducive to the development of an effective cell-mediated response [25]. Dimethyl ether spray, carbon dioxide snow and liquid nitrogen all produce cold thermal damage to the skin. Different types of devices and techniques are used to induce targeted cold injury to warts. Carbon dioxide slush (−79°C) is now less commonly used.
