What should you know about solid liquid nitrogen?

Liquid nitrogen boils at an extremely low temperature. When applied by a trained clinician, it rapidly cools a targeted area, causing treated cells to freeze. The skin may sting during application and later become red, swollen, blistered or crusted.

Freezing depth and duration are chosen for the lesion and body site. A single visit may be enough for some superficial lesions, while others need review or repeat treatment. The treated skin can temporarily look lighter or darker, and a small scar is possible.

Keep the area clean and avoid rubbing, shaving across it or removing a blister roof. Wash gently, pat dry and use the dressing or ointment recommended by the clinician. Protect healed skin from sunlight, since colour change can become more noticeable after exposure.

Do not handle liquid nitrogen yourself or use it on an undiagnosed growth. A lesion that has not been assessed may need a different treatment or a sample for diagnosis.

Ask the treating service for advice if pain is worsening, the area becomes increasingly hot or red, or drainage develops. Prompt assessment is needed for spreading redness, fever, extensive blistering, numbness that persists or bleeding that does not stop with gentle pressure.

Ask what lesion is being treated, whether freezing is appropriate, how to dress the area and when healing should be checked. Ask what skin colour change or scarring to expect at this site and what would require an urgent call.