A Nurse Practitioner’s Guide to Burn Classification

Roasted slowly to golden perfection, or burnt to a crisp in a fiery blaze? How do you like your marshmallows roasted? Summer is in full swing and with it common warm weather injuries. The 4th of July holiday is barely behind us, and already I have seen plenty of burns so far this season in the emergency department. I anticipate more to come. From an accidental seat plant into the flames of a campfire to sparklers gone awry it seems people can’t keep away from flames this time of year.

Those of us nurse practitioners working in the emergency department, urgent care, and even family practice can expect to treat a few burns this summer. So, I thought it would be a good time to do a quick review of burn classification.

There are a few different ways to classify burns. First, they may be classified based on the mechanism, or cause. Second, they may be classified based on degree and depth. Third, burns may be classified based on the extent, or total surface area of the burn. Lastly, once all other factors are taken into account, burns are classified on overall severity. In evaluating and treating patients for burn injuries, it is important to consider each of these modes of classification in your assessment.

Burn Classification by Mechanism or Cause

After assessing the ABC’s, airway, breathing, and circulation, the next step in treating a burn is to identify the mechanism of injury. The method by which the patient was burned gives you valuable information in determining the extent of injury you should expect. There are two main categories under which burn mechanisms fall, thermal and inhalation.

Thermal Burns

Thermal burns include scalding burns, contact burns, and burns from fires. Scalding burns are caused from heated liquids such as boiling water, grease or steam and can occur either by immersion into the liquid of by spilling. Fire injuries can be further divided into flash or flame burns. Thermal burns are the most common type of burn injury.

Inhalation Burns

Inhalation burns occur as a result of breathing in heated gasses or steam. These substances can cause injury to the airways and are the most common cause of burn related death.

Burn Classification by Degree and Depth

The skin is made up of layers including the epidermis, dermis, and subcutaneous fat. Burns are classified as first, second, third, or fourth degree depending on the layers of skin and underlying tissues involved.

First-Degree or Superficial Burns

First-degree burns damage the epidermis, the outermost layer of the skin, while the skin remains intact. They appear red, dry, and painful. Sensation of the affected area is not compromised. Common causes of first-degree buns include sunburn or brief contact with a hot fluid or surface. These burns heal within several days to a week without scarring. Burns that initially appear to be first degree may progress to second-degree burns including sloughing of the skin or blistering within hours to the next day following the initial injury.

Second-Degree or Partial-Thickness Burns

Second-degree burns may be classified as either superficial-partial thickness, extending into the papillary (superficial) dermis, or deep-partial thickness, extending into the reticular (deep) dermis. Superficial-partial thickness burns appear are red, painful, appear wet, and often form thin-walled fluid-filled blisters. They heal within two to three weeks, typically without scarring.

Deep partial-thickness burns extend into the deepest layers of the dermis. These burns appear red and white. Blisters associated with deep partial-thickness burns are thick-walled and often ruptured. Sensation may be diminished. Deep partial-thickness burns heal within three to six weeks and may scar.

Third-Degree or Full-Thickness Burn

Third-degree burns damage every layer of the skin, the epidermis, dermis, and subcutaneous tissue layer as well as the hair follicles. Third-degree burns have a dry, white, leathery appearance. Sensation of the affected area may be completely or partially comprimised as a result of damage to underlying nerves. Skin grafting is almost always necessary for treatment of third-degree burns.

Fourth-Degree Burns

Fourth-degree burns involve the underlying tissues, tendons, or bone of the affected area. These burns have a poor prognosis and often require extensive debriedment and reconstruction.

Burn Classification by Surface Area

Assessing burn size is essential for the treatment and management of burns. The size of the burn is directly related to severity. Burn size is measured as a percentage of total body surface area. There are three methods for assessing burn surface area.

The Rule of Nines

In adults, the “rule if nines” gives a rough estimate of the percentage of the body affected by the burn. The approximate body surface area made up by each body part is as follows:

• Head 9%
• Chest (front) 9%
• Abdomen (front) 9%
• Upper/ mid/ low back and buttocks 18%
• Each arm 9% (front 4.5%, back 4.5%)
• Groin 1%
• Each leg 18% (9% front, 9% back)

Lund-Browder Charts

Lund-Browder charts give a visual estimate of body surface area for infants and children depending on age. Children and infants typically have a larger head and neck surface area as a percentage of total body surface compared to adults so the rule of nines is not as accurate in these age groups. Corresponding Lund-Browder charts for adults are also helpful in determining body suface area affected by burns in these patients.

Estimation by Palm Size

The surface area of one’s palm is considered to be about 1% of the total body surface area. This measure can be used to give a rough estimate of burn size.

Burn Classification by Extent

Ultimately, the extent of a burn takes into account the burn mechanism, degree and depth, and body surface area involved. Age of the patient, coexisting injury, and location of the burn are also considered.

Minor Burns

Minor burns involve less than 15% of the total body surface area (TBSA) in adults, or less than 10% TBSA in children and the elderly. Full-thickness burns involving less than 2% of the TBSA ara also classified as minor burns. Minor burns do not pose a cosmetic or functional threat to the eyes, ears, face, hands, feet, or perineum.

Moderate Burns

Moderate burns include partial-thickness burns of 15-20% TBSA in adultsor  of 10-20% of TBSA in children and the elderly. Full-thickness burns of 2-10% TBSA that do not present a cosmetic or functional threat to the eyes, ears, face, hands, or perineum are also considered moderate burns. Moderate burns do not include those caused by high-voltage injury, inhalation injury, circumferential burns, or those in individuals with complicating health problems. Patients with moderate burns require hospitalization, but not necessarily at a burn center.

Major Burns

Major burns involve greater than 20% of the TBSA in adults, or greater than 10% TBSA in children and the elderly. Full thickness burns involving greater than 5% TBSA are also classified as major burns. Major burns also include high-voltage burns, known inhalation injuries, significant burns to the joints, face, hands, feet, or perineum, and burns accompanied with other injuries. Major burns require hospitalization at a burn center.

Understanding classification of burns is the first step in burn evaluation and treatment for nurse practitioners. Recognizing burns that require a higher level of care is essential as burns can pose significant cosmetic and functional complications. 

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