Putting salt and ice directly onto the skin is an extremely dangerous act that results in severe and rapid tissue damage. This practice, often associated with the “salt and ice challenge,” is a method of intentionally inflicting a full-thickness injury. The combination creates a localized, ultra-cold environment that can cause permanent disfigurement in minutes. Engaging in this challenge inevitably leads to serious medical consequences requiring specialized burn treatment.
The Science Behind Extreme Cooling
The extreme cold is rooted in a phenomenon called freezing point depression. When salt, typically sodium chloride, is introduced to ice, it dissolves into the thin layer of liquid water coating the surface. This dissolution interferes with the ability of water molecules to re-form a crystalline solid structure. The dissolved salt ions effectively lower the freezing point of the water well below the standard 0°C (32°F). To initiate melting, the process must draw energy from its surroundings in an endothermic reaction, rapidly pulling heat directly from the body’s tissue.
This rapid heat extraction causes the temperature of the ice and salt mixture to plummet dramatically. While pure ice on the skin remains at 0°C, the salt and ice mixture can easily reach temperatures as low as -17°C (1.4°F) to -28°C (-18°F). This intense, localized drop in temperature causes severe cold injury far faster than simple exposure to freezing air. The skin cannot replenish the heat quickly enough, leading to immediate tissue damage.
The Immediate Tissue Damage
The result of this extreme cold exposure is a localized injury that mimics both severe frostbite and a cold-induced thermal burn. Because the temperature drops so low, the skin’s natural defense mechanisms are overwhelmed almost instantly. The initial biological response is severe vasoconstriction, where blood vessels narrow to conserve core body heat, depriving the exposed tissue of warmth and oxygen. This localized cold rapidly leads to the formation of ice crystals within the skin cells, causing direct mechanical damage and cell death.
The injury progresses quickly, often resulting in second- and third-degree tissue damage within two to three minutes. First, the skin becomes red and numb, progressing to a waxy, pale, or hard appearance as the tissue freezes. A second-degree injury involves significant blistering as fluid builds up beneath the damaged epidermis and dermis layers. A third-degree injury destroys the skin entirely, making it feel leathery and hard, and potentially extending to underlying fat and muscle. Crucially, the extreme cold rapidly deadens the nerve endings, creating a false sense of pain relief that allows the person to sustain devastating injury.
Long-Term Consequences and Necessary Care
The intense cold injury often leaves behind lasting health issues. Permanent scarring is common, particularly with second and third-degree wounds that destroy the deeper layers of the dermis. The damaged skin may also experience permanent pigment changes, becoming lighter (hypopigmentation) or darker (hyperpigmentation). A significant concern is chronic nerve damage, or neuropathy, resulting from the rapid destruction of nerve tissue. This can lead to persistent numbness, loss of sensation, or chronic pain in the affected area, sometimes requiring surgical intervention, including skin grafts.
Immediate first aid involves removing the cold source and gently rewarming the affected area without rubbing or applying direct heat. The injured skin should be soaked in warm water, between 37°C and 39°C (99–102°F), for about twenty minutes. Any wet clothing should be removed, and the area covered with a clean, dry dressing. Immediate medical attention is necessary if the skin remains numb, develops large blisters, or appears hard and discolored after initial rewarming.