this: Burn (disambiguation) A burn is a type of injury that may be caused by heat, cold, electricity, chemicals, light, radiation, or friction. Burns can be highly variable in terms of the tissue affected, the severity, and resultant complications. Muscle, bone, blood vessel, and epidermal tissue can all be damaged with subsequent pain due to profound injury to nerve endings. Depending on the location affected and the degree of severity, a burn victim may experience a wide number of potentially fatal complications including shock, infection, electrolyte imbalance and respiratory distress. Beyond physical complications, burns can also result in severe psychological and emotional distress due to scarring and deformity.

Classification by degree

The most common system of classifying burns categorizes them as first-, second-, or third-degree. Sometimes this is extended to include a fourth or even up to a sixth degree, but most burns are first- to third-degree, with the higher-degree burns typically being used to classify burns postmortem. The following are brief descriptions of these classes:

• First-degree burns are usually limited to redness (erythema), a white plaque and minor pain at the site of injury. These burns only involve the epidermis.

• Second-degree burns manifest as erythema with superficial blistering of the skin, and can involve more or less pain depending on the level of nerve involvement. Second-degree burns involve the superficial (papillary) dermis and may also involve the deep (reticular) dermis layer.

• Third-degree burns occur when the epidermis is lost with damage to the hypodermis. Burn victims will exhibit charring and extreme damage of the dermis, and sometimes hard eschar will be present. Third-degree burns result in scarring and victims will also exhibit the loss of hair shafts and keratin. These burns may require grafting.
• Fourth-degree burns damage muscle, tendon, and ligament tissue, thus result in charring and catastrophic damage of the hypodermis. In some instances the hypodermis tissue may be partially or completely burned away as well as this may result in a condition called compartment syndrome, which threatens both the life and the limb and the patient. Grafting is required if the burn does not prove to be fatal.
• Fifth-degree burns result in hypodermis being burnt off, leaving blackened muscle, tendon, and ligament, with damage to compact bone, and spongy bone. Fat, nerves, veins, arteries, arterioles, and venules have been destroyed and the burn area is paralyzed as a result. Grafting or amputation is required, depending on the size of the burn area.
• Sixth-degree burns leaving blackened bone and damaging marrow tissue; these burns will definitely require amputation.