What is a burn?
A burn is a physical injury caused from exposure to any form of heat. These burns can be categorized based upon the nature of the heat source (burn type), depth of the burn (burn classification), and severity.
Types of Burns
The World Health Organization defines a burn as “an injury to the skin or other organic tissue primarily caused by heat or due to radiation, radioactivity, electricity, friction or contact with chemicals.” This definition emphasizes the four predominantly recognized types of burns—thermal, chemical, electrical, and radiation. These categories are determined based upon the nature of the heat source that is the cause of the burn.
Thermal burns are the most straightforward and are what people typically think about when discussing burns. Thermal burns are caused by exposure to a heat source such as a flame, boiling water, a hot stove, etc. Because thermal burns come from such diverse heat sources, they are further sub-classified as contact, flame, flash or scald burns.
- Contact burns, as the name suggests, result from skin contact with hot coals, glass, metals or plastics.
- Flame burns result from exposure to open flame. The burn worsens based upon the duration of the exposure and the intensity of the heat from the flame.
- Flash burns are a specific type of flame burn that results from very brief exposure to a highly intense heat.
- Scalds are burns caused by hot liquids.
Chemical burns are caused by exposure to either acid an (e.g. hydrochloric or sulfuric) or an alkali (e.g. ammonia or lime). The extent of the burn depends on the properties of the chemical, the tissue area involved, and the duration of the contact before cleansing. In general, alkali burns are more severe because alkalis tend to penetrate tissue more rapidly and deeply than acids do. Immediate treatment focuses on irrigating the tissue to stop the chemical reaction process. Because of the complexity of chemical burns, victims should seek immediate medical attention if they start going into shock; the burn penetrates the top layer of skin; the burn is near the eyes, hands, feet, face, groin, buttocks, or over a major joint; or the pain cannot be controlled with over-the-counter pain relievers
Electrical burns are caused when electricity passes through the body. Due to the nature of these burns, they can cause damage below the skin without reflecting the full extent of the injury on the surface. This makes electrical burns difficult to diagnose. In some cases they can directly affect important organs like the brain or heart. All of this makes medical treatment particularly important for electrical burns.
Radiation burns are caused by exposure to radiation such as UV, X-ray, or radio waves. The greatest danger from these burns is the potential to damage cellular structure which can potentially lead to cell mutation and cancer. Even the most common type of radiation burn, a sunburn, can have serious consequences over time.
Inhalation injuries are not one of the four major types of burns, but they are so common and so severe that they deserve special mention. Inhalation injuries occur in nearly one-third of all major burns and are a significant cause of death among burn victims. These injuries can take the form of smoke inhalation or burns to the inside of the throat.
Classification of Burns
Burn classification is a term used to describe the depth of a burn. Most people are familiar with the first three classifications—first, second, and third degree—but burns are actually classified all the way up to the sixth degree. Fourth degree burns are often fatal and fifth and sixth degree burns are typically diagnosed during an autopsy.