Degrees of Burns

Determining the Severity of a Burn by Depth and Surface Area

different degrees of burn
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Determining the severity of a burn usually depends on two key factors: how deep it goes (how far into the layers of skin the burn damage extends) and how wide it is (how much total body surface area it covers).

When to Call 911

There are other factors used to determine if a burn is critical enough for treatment by a specialized team at a burn center. They are covered below and any burn that matches those criteria warrants a call to 911. In many areas, ambulances or helicopters are able to take burn victims directly from the scene to a burn center, even if it's not at the closest hospital.

If you get a burn on your hand from the stove or the barbecue, chances are the severity of the burn is pretty mild and can handle a little home TLC. On the other hand (no pun intended), you could've done some serious damage and need to call 911 right now. Determining the severity of a burn is essential if you want to try to treat the burn at home.

Burn Degrees

Depth is measured in degrees of burns. First degree burns are superficial and don't open you up to infection or cause you to lose fluid. Second-degree burns, also known as partial-thickness, have damaged not only the outermost layer of skin, but extend into the main part of the skin where the hair grows and the sweat glands weep. Third-degree burns are also called full-thickness and have killed the skin all the way to the fatty tissue underneath (or even into the muscle).

  • First-Degree Burns
    • A first-degree burn refers to a burn injury where the surface of the skin is damaged, but the epidermis (the outermost layer of skin) is still intact, and therefore able to perform its functions (control temperature and protect from infection or injury). A first-degree burn is considered a superficial burn. When assessing the severity of burns to determine if a patient needs hospitalization, healthcare providers ignore first-degree burns.
  • Second-Degree Burns
    • This means damage that has extended through the epidermis and into the dermis (the second layer of skin). Second-degree burns also are known as partial-thickness burns. In determining the severity of burns, the presence of second-degree burns indicates a loss of skin function.
    • Blisters are the first sign of a second-degree burn. As the epidermis is destroyed, it begins to separate from the dermis. Fluid builds beneath it, causing blisters. Eventually, the blisters will spread into one another until the very thin epidermis falls away, exposing the raw dermis underneath.
    • Once the epidermis has separated from the raw dermis, the victim begins to lose fluid, heat, and the ability to block infection. The raw nerve cells of the dermis also mean second-degree burns are the most painful.
  • Third-Degree Burns
    • This indicates the burn has destroyed both the epidermis and dermis. The victim has the same trouble with fluid loss, heat loss, and infection that come with second-degree burns. Full-thickness burns also cause nerve death, so the victim may not be able to feel anything in the area of the burn.
    • There's no easy way to tell the difference between a deep partial-thickness burn (2nd degree) and a full-thickness burn (3rd degree) when looking at it in the field, so we don't try. Instead, all burns that are deep enough to separate the epidermis from the dermis are counted when determining severity. In other words, we count all burns that are bad enough to form blisters - or worse - when assessing burn severity.

Burn Surface Area

The width of the burn is expressed as a percentage of the body's surface area. We only count burns that are at least second-degree. First-degree burns do not need specialty treatment and are not considered critical. Burns that are at least second-degree and that cover more than 10 percent of the body's surface area are generally considered to be critical in most locations, but be sure to follow your local protocols. To determine the total burned surface area in the field, use the Rule of Nines.

Specific Critical Burns

Most burns are determined to be critical by the depth and width of the burn. However, burns on important parts of the body can be considered critical regardless of the overall size of the burn itself.

Burns to these areas are considered critical, even if this is the only thing burned:

  • Face
  • Burns that completely encircle the hands or feet
  • Genitals

Burns still must be second-degree or worse to be considered critical. First-degree burns are never counted.

Treatment of Critical Burns

Treating burns is the same regardless of how critical they are. Complications of critical burns include infection, hypothermia, and dehydration. The most important step a lay rescuer can take for a critical burn is to call 911.

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