Determining the Severity of a Burn

Combine Depth and Size of Burns to Decide if You Need Medical Attention

Heating pad burn
Heating pad burn. (c) Francisco de La Roxa

If you get a burn on your hand from the stove or the barbecue, chances are it's pretty mellow 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.

Do you know how to tell the difference?

Severe Burns

There are several factors used to determine if a burn is critical enough for treatment by a specialized team at a burn center.

Any burn that matches these 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 unit, even if it's not at the closest hospital.

Deep and Wide

Determining if a burn is critical depends on two things: 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). 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).

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

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

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.


Knowlin, L., Stanford, L., Moore, D., Cairns, B., & Charles, A. (2016). The Measured Effect Magnitude of Co-Morbidities on Burn injury Mortality. Burns : Journal of the International Society for Burn Injuries42(7), 1433–1438.

Thom D. Appraising current methods for preclinical calculation of burn size - A pre-hospital perspective. Burns. 2017 Feb;43(1):127-136. doi: 10.1016/j.burns.2016.07.003.