What should you know about liquid nitrogen therapy?

Liquid nitrogen is a cryogen used by a trained clinician with a spray or contact applicator. The cold damages the targeted surface while the surrounding skin is protected as far as possible. You may feel a sharp cold sensation, stinging, or burning during and shortly after treatment. The area can become red, swollen, blistered, or crusted. The visible lesion may darken and gradually shed as new skin forms.

The technique and number of applications depend on the lesion, its thickness, its site, and the surrounding skin. A diagnosis matters because freezing is not appropriate for every spot.

Clean the site gently and keep it protected according to the instructions you receive. Leave a blister roof intact unless your clinician tells you otherwise, and avoid scratching or peeling a crust. Reduce friction from clothing or footwear where relevant. Use only recommended products on the area. Once healed, protect exposed new skin from sunlight to reduce lingering colour change.

Read about the material in [Liquid Nitrogen](/materials/liquid-nitrogen/) and the clinical procedure in [Cryotherapy (Lesion Removal)](/treatments/surgical-dermatology/cryotherapy-lesion-removal/).

Contact the treating clinic if pain, redness, warmth, or swelling keeps increasing, or if drainage becomes thick or unpleasant-smelling. Fever, red streaking, uncontrolled bleeding, or a wound that is not healing needs medical assessment. Report numbness that persists or a reaction that extends well beyond the treated area.

Ask what lesion is being treated, how deep the freeze is expected to reach, how to dress the area, and what appearance is normal during healing. Clarify whether you need a follow-up examination if the lesion remains or changes.