Skin cross section

Cross section of human skin (click to view)

The skin is complex system that plays an important role in protecting the body from infection and in regulating temperature and fluid retention. If enough of the skin is damaged, the body losses its ability to control these functions.

The skin has three main layers:

  • Epidermis - the outer layer of the skin
  • Dermis - the middle layer made up of elastic fibers and collagen where smaller blood vessels, nerves, and sweat glands reside
  • Hypodermis or subcutaneous layer - the soft tissue below the dermis, containing fat, larger blood vessel and nerves, hair follicle roots, etc.

Burns are wounds to the layers of the skin caused by exposure to heat, chemicals, electricity, radiation, etc. Unlike other types of wounds, burns are progressive and can continue to cause damage for as long as the body is in contact with the burning source. A burn incident fact sheet for 2012 is available from the American Burn Association.

For educational resources related to burns (i.e., scalds, electrical burns, fire/burn safety for older adults, gasoline safety, summer burn safety, etc.), go to the American Burn Association Educational Resources page.

The severity of a burn depends on:

  • The temperature or strength of the burning source
  • The exposure duration
  • The depth, surface area, and location of the burn
  • The age and/or medical condition of the patient (i.e., the very young, the elderly, and those with chronic medical conditions are more susceptible to burns)
In humans, only the epidermis has the ability to regenerate itself. Burns that extend into the dermis and hypodermis may result in permanent disfigurement and disability. Very large and severe burns can even be life-threatening.

Classifying Burns

Burns are classified by mechanism of injury (source), depth, surface area, location, and patient. Understanding these classifications can help you determine the severity of a burn, how to care for the patient, and when to call for more advanced medical personnel.

Friction burn (rope burn)

Friction burn (rope burn)

By mechanism of injury
Electrical burn

Electrical burn

Mechanisms of injury that cause burns include the following:

  • Chemicals (e.g., acids, bases, oxidizers, etc.)
  • Cold (e.g., frostbite, exposure to cold substances, etc.)
  • Electricity (e.g., electrical sources, lightning, etc.)
  • Friction
  • Heat (e.g., flame burns/explosions, scalding liquids, hot metals and other objects, steam, super-heated air, etc.)
  • Radiation (e.g., sunlight, tanning beds, overexposure to x-rays, etc.)

These mechanisms can vary in strength and the type of tissue damage they cause. For example, burns caused by chemicals, electricity, and fire/explosions are always considered critical.

By depth

First-degree (superficial) sunburn

Burns are frequently described in terms of their depth within the body. The terms first-, second-, and third-degree burns have been in use since the 16th century (coined by the French barber-surgeon Ambroise Pare) and are still in use today. In recent years, burn depths has been given more descriptive names: superficial for first-degree burns, partial thickness for second-degree burns, and full thickness for third-degree burns. They have also been expamded to include additional degrees as described below.

  • First-degree (superficial) - characterized by redness (erythema), dry skin, and pain
    • Skin layers affected: Epidermis
    • Healing time: Approximately 1 week
    • Possible complications: Premature skin aging; skin cancer
  • Second-degree (superficial partial-thickness) sunburn

    Second-degree (superficial partial-thickness) sunburn

    Second-degree burn (hot coffee scald)

    Second-degree burn (hot coffee scald)

    Second-degree (superficial partial thickness) - characterized by redness with clear blisters, moist skin that blanches with pressure, and pain

    • Tissue affected: Epidermis and superficial (papillary) dermis
    • Healing time: 2-3 weeks
    • Possible complications: Localized infection/cellulitis
  • Second-degree (deep partial thickness) - characterized by red-and-white, moist skin with bloody blisters and pain
    • Tissue affected: Epidermis and deep (reticular) dermis
    • Healing time: Weeks
    • Possible complications: Possible progression to third-degree burn; scarring (may require excision, skin grafting, etc.)
  • Small third-degree burn

    Small third-degree (full thickness) burn

    Third-degree (full thickness) - characterized by stiff, dry, white-brown skin with little or no pain due to nerve tissue damage

    • Tissue affected: Epidermis, dermis, and subcutaneous layers of the skin
    • Healing time: N/A; requires excision
    • Possible complications: Scarring; contractures; amputation
  • Fourth degree burn

    Fourth degree burn

    Fourth-degree (full-thickness with muscle and bone damage) - characterized by black, charred, dry skin with eschar and no pain

    • Tissue affected: All skin layers, muscle, and bone
    • Healing time: N/A; requires excision
    • Possible complications: Amputation; significant functional impairment, gangrene, death

Some sources number burn degrees up to six as in Degrees of Burns (Buzzle). In this scale, the fourth-degree burn affects skin and muscle tissue: the fifth-degree burn affects skin, muscle, and bone; and the sixth-degree means the body charred throughout, including charred bones. The sixth-degree is identified in autopsy only because burns of this magnitude cannot be tolerated and result in death.

By surface area

The severity of a burn, especially a second-, third-, or fourth-degree burn, can be determined in part by its surface area on the body. Systems for estimating the total body surface area (TBSA) of a burn are listed in this section.

  • Rule of nines- a method for estimating the TBSA of an adult by dividing the body into regions as indicated below:
    • Head and neck: 9%
    • Each arm: 9%
    • Each leg: 18% (anterior: 9%; posterior: 9%)
    • Chest: 9%
    • Abdomen/anterior pelvis: 9%
    • Upper back: 9%
    • Lower back/buttocks: 9%
    • Genitalia/perineum: 1%
  • Lund and Browder chart- a method for estimating the TBSA of patients similar to the rule of nines but taking into consideration the body’s development at different ages.

    Lund and Browder Chart

    Lund and Browder Chart for TBSA Estimation

Typically, these measurements are for second-degree burns and deeper. This is because first-degree burns (e.g., sunburns, etc.) rarely cause any immediate health risks or permanent scarring.

By location

Burns in certain locations of the body are considered more serious than similar burns in less critical body locations. Critical burns include those to:

  • The face, eyes, ears, neck, or throat (including inhalation injuries)
  • The chest (if it causes breathing difficulty)
  • One or both hands
  • One or both feet
  • Any joint (when it affects mobility)
  • The circumference of the trunk or any extremity (because of problems with blood flow)
  • More than one body region (i.e., second-degree burns in 10-15% TBSA; third-degree burns or higher in 2% TBSA)
  • The genitalia and/or perineum

More advanced medical care should be called  for any critical burn you encounter.

By patient

Burns have a more debilitating effect on young children, the elderly, and those with chronic medical conditions.

  • Pediatric burns:
    • Children have an increased risk of morbidity because of:
      • Greater surface area per pound/kilogram of body weight
      • Greater evaporative water loss and limited body temperature regulation
      • Disporportionately thinner skin (especially children less than 2 years of age) that make second- and third-degree burns more likely
    • Children under 3 usually have scalds while older children are burnt by open flame or contact with hot objects
    • Very small children may present with electrical burns on the mouth or hands from sucking on electrical cords or inserting objects into exposed electrical outlets
    • Any second-degree burn or higher should be seen by the child’s physician as soon as possible
  • Geriatric burns
    • Older adults have increased risk of morbidity because of:
      • Daily tasks like cooking, boiling water, making a fire, smoking, etc. may become more difficult and lead to accidental burning
      • Thinner, less sensitive skin makes severe burns more likely
      • Weakness, lack of mobility, confusion make make escape from a burning source impossible
    • Any second-degree burn or higher should be seen by the patient’s physician as soon as possible
  • Burns affecting patients with other medical conditions
    • Patients with diabetes may be at increased risk for leg burns due to diabetic neuropathy; they also do not heal well and have increased complications related to reconstructive surgery
    • Patients with chronic respiratory problems (e.g., asthma, chronic obstructive pulmonary disease [COPD], etc.) may be more adversely affected by inhalation injuries or burns that affect breathing.
    • Pregnant women are rarely severely burned, but when it happens, there can be complications affecting both mother and baby, including fluid loss, hypoxemia, and sepsis.

Caring for Burns

This section includes general care steps as well as specific care for different mechanism of injury.

General care steps

General care steps apply to all suspected burns and begin with assessment of the scene and patient:

  1. Size up the scene carefully. If you suspect the patient has been burned, determine the mechanism of injury and make sure you can safely approach the patient without being burned yourself.
  2. Remove the patient from the burning source. If you can safely approach the patient, make sure to remove the patient from the burning source.
  3. Perform a primary assessment and pay attention to the airway and breathing. If you detect breathing difficulty or a critical burn, call for more advanced medical personnel, monitor vital signs, and administer emergency oxygen.
  4. Perform a secondary assessment beginning with the head-to-toe exam. Note areas of the body that have been burned and estimate the total body surface area affected. Also check for burns in critical locations. If the burn is due to electricity or explosion or if the burn caused the patient to fall or suffer other trauma, check for other injuries. For electrical burns, look for an entry and exit wound.
  5. Provide specific care for the type of burn sustained (see Specific Care Steps below).
  6. Minimize shock by having the patient rest, maintaining the patient’s normal body temperature, minimize pain, and reassuring the patient.
Specific care steps

To provide specific care for burns (see step 5 above), determine the mechanism of injury.

  • For chemical burns:
    • Call for more advanced medical personnel
    • Flush with water at least 20 minutes or until emergency medical personnel arrive and take over
  • For frostbite/cold exposure:
    • Immerse the affected part in 100 to 105 °F (38 to 41 °C) for about 20 minutes or until normal color returns to the area
    • Pat the area dry carefully; avoid rubbing the area
    • Loosely bandage the area with dry, sterile dressings and bandages
    • Protect digits from rubbing each other by wrapping them separately or by placing folded gauze pads in between the digits before bandaging
    • Do not break blisters or rub the area to try to improve circulation
  • For electrical burns/lightning strikes:
    • Use safety precautions to prevent exposure. Handle electricity with care and prevent accidental exposure, especially by children. Turn off power before approaching the patient. For lightning, prevent exposure by planning activities in, on, and around the water when the weather is fair. Whether swimming, boating, diving, etc., leave the water immediately at the first flash of lightning or sound of thunder. Move everyone indoors and away from metal pipes, plates, glass, electrical equipment, etc.
    • Call for more advanced medical personnel
    • Care for life-threatening conditions first
      • Check pulse and breathing; be prepared to perform CPR
      • Monitor vital signs
      • Lightning strikes and high-voltage electrical incidents may cause trauma, including spinal injuries
    • Identify and care for the entry and exit wounds (often present with electrical wounds)
      • If the patient complaints of a burning sensation, flush the wound with water until cool
      • Carefully pat the wounds dry and loosely bandage
    • Look for other injuries, such as broken bones, bumps or bruises from falling, etc.
  • For friction burns:
    • Flush with water to cool the burns and clean any wounds caused by scraped away skin
    • Cover and bandage as you would any soft-tissue wound
  • For thermal (heat) or radiation burns:
    • Cool the burned area with large amounts of water to stop the burning and to lessen pain; do not use ice or ice water
    • Do not apply any ointments, creams, commercial oir home remedies, butter, oil, etc.
    • Do not break blisters or try to remove clothing or melted materials in the wound
    • Cover the burning area with a sterile dressing and bandage loosely to protect against infection