Burn area estimation or percentage of burns.

4) Dear burn surgeon, my son-in-law who is 34 years old was admitted to hospital with 22 % burns. Doc, is this a major burn and is it life threatening?
charulata s
sri lanka+
Dear Charulata,
You have raised three important issues:
1) What does percentage burn mean?
2) Why do we need to calculate the percentage of burn?
3) How do we calculate the percentage of burn.

1. What does percentage burn mean?
If we imagine and spread out the entire skin of our body it will cover 0.2-0.3 m2 while for an adult it will cover 1.5-2.0 m2 or 1.75 square meters approximately.
If we say that the face or the chest was burnt we will not have a clear idea about how much area is burnt, hence the area of skin burnt is mentioned in percentage as a standard for comparison. The entire skin area of the body is that is burnt is referred to as TBSA or total burn surface area.

2. Why do we calculate the percentage of burns?
Calculating the percentage of burns tells us if it is a minor burn, moderate burn or a major burn.

Minor burn- less than 10% burn area in children
-less than 15% burn area in adults
-burns that do not involve the head , feet, hands or perineum (genital and anal area) are included in this group

Moderate burn- burn area of 10-25 % in children
-burn area of 15-25% in adults
-2nd degree superficial burn of head, hands, feet or perineum are also included in this group

Major burn- burn involving more than 25%TBSA
others that are included in this group:
-full thickness burns more than 10% TBSA
-deep burns of the hands, feet, head, or perineum
-patients who have inhaled a lot of toxic smoke and suffer damage to lungs (smoke inhalation injury)
-high voltage electrical burns
-chemical burns

As the percentage of burns increases, so do the problems faced with management and healing of the burn wound. With increasing are of burn, more fluid is lost from the body and replacement in the form of intravenous fluids becomes a necessity. Thus children with more than 10% burn area and adults with more than 15% burn area will need to be admitted to the hospital for intravenous fluid administration. Furthermore as the percentage of burn increases, the rate of complications, sepsis or infection and period of recovery all increase. The availability of skin for skin grafting also decreases. Thus knowing the area of burn is extremely important before we start to treat the burn itself.

3. How do we calculate the percentage of burns?
The simplest way is ‘the rule of nine’ by wallace i.e. each part of the body is 9% or multiple of nine.



Head - 9%
Each upper limb - 9%
Anterior trunk – 18%
Posterior trunk – 18%
Each lower limb – 18% x 2
Genital area – 1%
Total =100%




This works well in adults but newborn, infants and preschool children have larger head, smaller body and lower limbs. The Lund and Browder chart accurately helps to calculate the burn are in these patients.

Lund and Browder Chart






If the area of burn is small and does not include whole parts of the body one can simply use the palm of the patient as representing 1% and calculate the burn area. For e.g. five palms that cover the area of the burn will mean 5% burn.
It is important to use the palm size of the patient and not your palm size!!!!!

Therefore charulata, a 22% burn is a moderate burn and generally should not be life threatening unless there is an associated serious inhalation injury to the lungs or there is uncontrolled infection.

Dear Burn Surgeon,
Can you please tell me about the first aid for burns and how to avoid burns in general?
Susan A.
California.
Watch out for my next blog for the answer!!

Degree of burns, Avoid burns in kitchen, temperature at which burn occurs, ice on burns?

1. Dear burn surgeon, I am always worried my naughty son will suffer burns since he is always around me in the kitchen. Also please tell me at what temperature does a burn really occur?
Vanessa A, ST Louis, MO
Dear Vanessa,

You have raised an important issue. In fact 90% of burns in children occur at home and the kitchen is the most common area where burns occur. The simplest and best way to prevent burns in the kitchen is to bar children from entering the kitchen. In my kitchen I had an extra door fitted, which came up to my son’s neck level so that my wife could see only my son’s face and he could not enter the kitchen. I had to increase the height of the door thrice!!! till he was mature enough to take care of himself. In case of infants or babies it is better to keep them in a movable baby bed with bars, along with some toys so that he can’t move out and keep the baby bed close to your kitchen so he does not miss you and you can always keep an eye on him. You could also increase the height of the cooking area and the shelves so that the child cannot reach any of these sites. Matchsticks and lighters should be kept in a safe area. Do not use table cloth in the kitchen as children will tend to pull on it and spill hot food, soups etc over themselves. In general, do not leave any hotstuff likely to cause burn unattended, when you have a child in the house. It is our responsibility to avoid burns in children.All electrical devices in the kitchen should be out of reach of children so as to avoid an electrical burn or shock. Electrical plug points should be child safe and wirings should not be exposed.

To discuss your second question,
The normal body temperature is 37 c or 98.4 f. Hence the body can withstand a few degrees more or less. However at temperatures of 40-44 c or 104 to 111.2 f the tissues suffer damage. The cellular proteins denature and even the cellular enzymes and pump mechanisms stop functioning. Over 44 c or 111.2 f it is difficult for the cells to repair this damage. So vanessa be careful when temperatures cross 40 c.

2. Dear burn surgeon, I read that immediate cooling of a burn helps, can I put ice on the burnt areas ?
Kimberly james, NY

Thank you Ms Kimberly for your question. Burns occur at high temperatures that begin to damage the skin and body tissues (See Q1). Logically if this temperature is immediately lowered, less damage should occur. Cold running water is the best way to do this. Hold the burn area under the cold running water till pain subsides for a few minutes (water conducts the heat away from the skin). For big severe burn areas one should be careful and avoid immersing in cold water as this can result in hypothermia (lowering of body temperature) and shock. Application of ice should be avoided for reasons of hypothermia as well as to prevent causing a cold burn (frostbite).

3. My friend’s daughter has a burn on the leg. The doctor says that it is a second degree deep burn and may need a special procedure called skin grafting.
Please explain this.
Lucio Paul M
S Africa

In what manner a burn wound will heal depends on how much damage the burn has caused the skin and body tissues. This is known as the depth of the burn and to understand this concept, one must know the layers of the skin.


In simple terms the skin has two layers
1) Epidermis – superficial or upper
2) Dermis- deep or lower

The fat, muscles, nerves, bone and organs lie below these 2 layers of the skin.

If only the epidermis is damaged it is called a 1st degree burn. This is akin to sunburn. There is redness (erythema) of the skin, pain and blanching (skin becomes pale on pressure).

When the epidermis and the upper part (superficial layer) of the dermis are damaged, it is called a 2nd degree superficial burn. This burn is painful (sensory nerves endings are not damaged), has blisters (fluid collects between epidermis and dermis) and burnt areas will still blanch when pressure is applied. The hair follicles and dermal glands are usually unaffected.

When the epidermis and most of the dermis is damaged, it is called a 2nd degree deep burn. This burn has less pain (sensory endings are affected) blood flow is affected and so the skin appears pale or white, may have small or no blisters (as deeper layers of dermis is burnt, less fluid can exude or pass out) and the hairs can be easily pulled out (as both hair follicles and glands of dermis are damaged).

When the epidermis and the whole of the dermis are completely damaged, it is called a 3rd degree burn. The burn area appears waxy white or brown or black depending on whether the burn has charred the skin. There is no pain as all the skin sensory elements are destroyed. Since all blood supply in the skin is destroyed the skin appears depressed (lower than the surrounding normal skin) and sometimes clotted blood vessels are seen in this burn area. When you touch the skin there is a leathery feel and all the hair are lost and dermal glands are totally damaged.

When the burn damages skin completely and extends into the underlying structure subcutaneous fat, muscles, tendons, blood vessels and bone joints it is called a 4th degree burn.

Why did I give you all these details?
Well, once you know the depth of the burn you can fairly predict the healing pattern and suggest the course of management though sometimes a superficial burn can become deep over course of time from many reasons.

The skin heals by regeneration of epithelial cells which are present in the hair follicles, sweat glands and sebaceous glands that are present in the dermal part of skin. Whether a burn wound will heal will depend on the depth of the burn and what percentage of hair follicles, sweat glands and sebaceous glands are destroyed.

Since only the epidermis is damaged in a 1st degree burn, the skin is easily regenerated and healing occurs without scar formation. 1st degree burn heals by simple ointment applications in about seven days.

2nd degree superficial burns do not damage the hair follicles and dermal glands but they take more time and tend to heal in 2-3 weeks.

2nd degree deep burns and 3rd degree burns will damage the hair follicles and dermal glands and therefore will not heal spontaneously. Instead of regeneration of skin they will end up as red raw area (granulation tissue) without skin. Hence one needs to remove skin from another part of the body and apply this on the burn areas after clearing the burn wound of all the dead tissues (debridement). This procedure is called skin grafting.

4th degree burns need more tissue than a thin skin graft and therefore a flap (tissue that includes skin, fat, muscle or bone) are required. I shall explain the skin grafts and flaps in detail later.

Uncommonly 2nd degree deep burns may heal between 3-4 weeks but they often end up with severe scaring and contractures (joints movement is restricted because of shortage of skin)
I hope this explanation will satisfy you.