Degrees of burns

Burns are caused by a transfer of energy from a heat source to the body which may be through conduction or electromagnetic radiation. Anybody is prone to get a burn injury anytime. Young children and elderly persons are particularly at high risk for burn injury. Burns are categorized by thermal, radiation or chemical injuries.

Pathophysiology of burns: Whatever the type of injury may be, the effect of burns over the skin and vicera are the same. Tissue destruction occurs from coagulation, protein denaturation or ionization of cellular contents. Each system will respond differently depending upon the area involved and they are treated accordingly.

The severity or the depth of the injury depends upon
1. The temperature of the burning agent
2. The duration of contact with the burning agent

Burn care is planned depending upon the extent and depth of the injury, and then proceeding with the three phases of burn care which are the emergent/resusciative phase, acute/intermediate phase and the rehabilitative phase.

Recognizing different degrees of skin burns: Burns are classified according to the depth of tissue destruction and are identified as
1. Superficial partial-thickness injuries (first degree)
2. Deep partial-thickness injuries (second degree)
3. Full thickness injuries (third degree)

1. Superficial partial-thickness injuries (first degree): The epidermis of the skin is destroyed or completely injured and a portion of the dermis may be injured. The wound is very painful and appears red and dry. The skin blanches with pressure. There is some amount of tingling sensation that is felt. The skin is supersensitive (hyperesthesia) and the pain is soothed by cooling. It looks like a sunburn or it may be blistered. A minimal edema will be noticed in some people, many do not present with edema. The skin over the blister peels on its own or can be removed in a sterile way and there is complete recovery within a week.

2. Deep partial-thickness injuries (second degree): This involves complete destruction of the epidermis and the upper layers of the dermis, and slight injury to the deeper layers of the dermis. The wound is painful, hyperesthetic and is very sensitive to cold air. The color appears to be mottled red and exudes fluid. The area is blistered and has surrounding edema. Blanching of the burned tissue is followed by capillary refill which denotes that there is blood supply to those areas involved. The hair follicles over the area remains intact. They are healed in 2 to 3 weeks time. Some scarring and depigmentation occurs. Care should be taken to prevent infection, if left uncared, the infection may convert it to third degree.

3. Full thickness injuries (third degree): Here there is total destruction of epidermis, dermis and in some cases the underlying subcutaneous tissues are also destroyed. The color of the wound varies from widely from white to red, brown or black which indicated poor blood supply and necrosis. The burnt area is usually painless because the nerve fibers are destroyed. The wound will have a dry, pale white leathery or charred appearance. The skin over the affected area is broken with the fat exposed and the skin around is edematous. The hair follicles and sweat glands are also destroyed. They require definite surgical procedures like sloughing, grafting or even amputations. Scarring and loss of contour and function develops as a part of healing.

The degree of skin burns are also identified by three methods:
1. Rule of nine
2. Lund and Browder method
3. Palm method

1. Rule of nine: The rule of nine is the quick way of calculating the percentage and degree of burns with the body surface area as a indicator. They are calculated by assigning percentages in multiples of nine to the body part that is involved. The calculation goes as head-9%, chest and abdomen-18%, back-18%, both hands-18%, perineum-1%, both legs-36% which covers totally 100%.

2. Lund and Browder method: The extent of burns are calculated by dividing the body into very small areas and providing the estimate of the proportion of body surface area (BSA) accounted for by such body parts, through which we obtain a reliable estimate of the total BSA burned. Here, the initial evaluation is made immediately on arrival to the hospital and is revised on the second and third postburn days, because the demarcation is not clear until then.

3. Palm method: If the burns are scattered at different parts of the body, this particular method is used for calculating them. This method is very simple, where the size of the palm are used for assessing the extent of burns.

Recognizing the degree of skin burns is very important to provide appropriate treatment. It is important for each and every one of us to learn how to identify the degree of burns to provide first aid.