This page deals with the type of injury called "burns"; for other meanings of "burn" see burn (disambiguation)

In medicine, a burn is a type of injury to the skin caused by heat, electricity, chemicals, or radiation (an example of the latter is sunburn).

Immediate first aid for burns consists of immersing the injured area in cool clean water to cool the injured tissues.

There are three degrees of burns.

• First-degree burns are usually limited to redness and pain at the site
• Second-degree burns additionally have blistering of the skin
• Third-degree burns additionally have charring of the skin (or eschar formation).

Burns that injure the tissues underlying the skin, such as the muscles or bones, are sometimes characterized as "fourth-degree burns". Serious burns, especially if they cover large areas of the body, can cause death; any hint of burn injury to the lungs, for example through smoke inhalation, is a medical emergency.

Chemical burns are usually caused by chemical compounds, such as sodium hydroxide (lye), silver nitrate, and more serious compounds (such as hydrochloric acid). Note that most chemicals (but not all) that can cause moderate to severe chemical burns are strong acids or bases. Nitric acid is possibly one of the worst burn-causing chemicals, as an oxidizer. Most chemicals that can cause moderate to severe chemical burns are called caustic.

Electrical burns are generally symptoms of electrocution, being struck by lightning, being defibrillated or cardioverted without conductive gel, etc. Survival of severe burn injuries is markedly improved if the patient is treated in a specialized burn center rather than a hospital.

Scalding is a specific type of burning that is caused by non-solid hot material: liquid and/or steam, usually water and vapour, sometimes oil (especially for cooks). It is usually regional and usually does not cause death. However, deaths have occurred in more unusual circumstances, such as when people have accidentally broken a steam pipe.

See also

• Cold burn