Why should a large, severe burn not be put in cold water?

Burns are grouped by how deep they go. A superficial, or first-degree, burn affects only the outer layer of the skin and causes pain, redness and swelling. A partial-thickness, or second-degree, burn reaches the layer beneath as well, and also causes blisters. A full-thickness, or third-degree, burn damages the deep layers of the skin, which may look white or blackened. Pain is not a reliable guide: some of the most serious burns hurt very little.

For a minor burn, the first step is to cool it. Run cool water over the area, or soak it in cool water, for 5 to 30 minutes, but do not use ice water. Calm the person, and once the burn has cooled, cover it with a clean, dry bandage and protect it from pressure and rubbing.

Just as important is what not to do. Do not put butter, oil, ice, creams or any household remedy on a burn. Do not break blisters or peel away dead skin, and do not try to remove clothing that is stuck to the burn. A large, severe burn should not be put in cold water, because this can cause shock.

Some burns need emergency help at once: burns about the size of the person's palm or larger, deep burns, burns caused by chemicals or electricity, and any burn where the person shows signs of shock or has breathed in smoke.