Identifying the Severity of a Burn

When giving first aid to a burn victim, the first thing that needs to be done is to identify the severity of the burn. Knowing how bad the burn is helps when deciding how to treat the burn, or if the burn victim should be given emergency assistance. There are 3 common levels of burn identification with two newer terminologies being used to identify serious burns.

There are 3 levels of burns that have been used over time, first-degree, second-degree and third-degree. The higher the number of the degree, the more serious the burn. First-degree burns are minor burns (superficial); this classification of minor or superficial means that the damage is only to the first layer of skin.

First-degree burns can be treated at home and are usually quick to heal as compared to second-degree and third-degree burns. In first-degree burns the skin is still able to function such as controlling body temperature, and protecting the body from infection and foreign objects.

Second-degree burns are when the damage from the burn goes deeper than just the first layer of skin or into the dermis, which is the name for the next layer of skin. The new term for these burns is “partial-thickness burns”. These types of burns have some degree of loss of skin function. A visible sign of second-degree burn is the presence of blisters. When the first layer of skin falls away from the dermis; this causes fluid loss, which leads to heat loss and the inability of the skin to prevent infection. Nerve cells that are located in the dermis are exposed during second-degree burns, which make these burns more painful.

The new term for third-degree burns is, “Full-thickness burns”. This degree of burn severity is when the first layer of skin (epidermis), the second layer of skin (dermis) and the nerves are destroyed. This level of damage leads to fluid loss, heat loss, and infection.

It is often difficult to determine the difference between second-degree and third-degree burns when on the site of injury and sometimes the degree is not determined until the individual is in the care of a burn unit or hospital emergency room. Any burn in the field where there are blisters or worse are considered to be serious burns and are treated as such.

Seriousness of a burn is determined not only by the damage to the skin layers and nerves but the size of the burn (how much of the area of the body is burned). The size of a burn is not easy to determine because we all have different shapes, sizes and weights. There is no universal scale to determine the severity of a “size” of burn. The weight of a person does make a difference when it comes to how severe a burn is. The same area of skin burned is more serious on a person weighing 90 pounds than it is to a person weighing 200 pounds.

Rule of Nines:

To try to come up with a universal way of determining the severity of the size of the burn, a percentage of total body area is used. This percentage of body area is measured by the “Rule of Nines”, or how much skin it takes to cover our arms, legs and other body parts. The body is divided into eleven sections in order to make the “size call”.

These are the eleven body parts:



Right Arm

Left Arm


Upper Back

Lower Back

Right Thigh

Left Thigh

Right Leg

Left Leg

Each of these body parts takes about 9% of the body’s skin to cover it (thus the “Rule of Nines”). All together these sections account for 99% of the body. The last percent is made up of the genitals.

The “Rule of Nines” is applied by adding up all the parts listed above where there are blisters or worse. In other words if there are blisters covering the head and the chest than 18% of the body is burned, if blisters cover the head, chest, and abdomen than 27% of the body is covered, etc. To be considered the head, it must be total coverage, if it is just the face it is considered to be 4.5%.