Injury: Burns and Scalds
Injury: Burns and Scalds
Burns are injuries caused to the skin or underlying tissues by direct heat or extreme cold; scalds are burns caused by hot liquids or gases (such as steam).
The severity of burns is measured in two ways: by the depth of the burn (see sidebar) and by the size of the affected area. Doctors use the
“rule of nines” to evaluate how much of a person's total body surface area (TBSA) has been burned. In adults, the head and neck together count as 9 percent of the body; each arm also counts as 9 percent. The front of the trunk, the back, and each leg are considered to each represent 18 percent of the TBSA. Doctors count only second- and third-degree burns in estimating the affected areas of the body.
Thermal burns (and scalds) are defined as burns caused directly by heat or by chemical reactions that release heat. They are divided into several categories according to the specific cause:
- Flame burns. This type of burn results from direct contact with fire. Flame burns may take the form of a sudden flash burn produced by a flammable liquid or gas igniting. Pouring lighter fluid on burning charcoal is a common cause of flash burns.
- Contact burns. These burns are caused by touching a hot object like a heated iron or cooking pan. Scalds are contact burns caused by hot liquids or gases.
- Electrical burns. These can be caused by contact with a live electrical wire or in rare cases by lightning. Electrical burns are serious because they can cause serious injury to internal organs that is not obvious from the size of the skin burn.
- Radiation burns. Radiation burns can be caused by welding equipment, radiation therapy for cancer, or overexposure to sunlight or tanning equipment. Sunburn is a common form of radiation burn.
- Chemical burns. Chemical burns can be caused by either strongly alkaline materials like lye, or by strong acids like sulfuric acid and nitric acid. Some acids are strong enough to eat through the skin and muscles down to the underlying bone.
Thermal burns affecting a person's airway can be as dangerous as burns affecting the surface of the body. The tissues of the airway can be burned by breathing in superheated air from a fire, toxic gases, smoke, or steam. In the United States, most people who die in house or office fires die from smoke inhalation rather than from skin burns.
Skin can also be burned by exposure to cold, either by lengthy exposure to cold outdoors (frostbite) or by brief exposure to extremely cold materials like dry ice.
The experience of a burn varies considerably depending on the cause of the burn, the parts of the body that are affected, the severity of the burn, and the situation in which the burn occurred. Human soft tissue will burn at any temperature above 115°F (46°C). Most burns are accidental; however, about 10 percent of cases of child abuse involve intentional burning or scalding of the child.
Degrees of Burns
Burns are classified according to the degree of injury that they cause. Some doctors prefer to classify them according to the layers of skin and muscle tissue that are injured. Both methods of classification are outlined here:
- First-degree burn: Also known as a superficial burn, this type of burn affects only the epidermis, the outermost layer of skin. It produces reddening and minor pain but no blisters.
- Second-degree burn: Also called a partial-thickness burn, a second-degree burn injures the upper level of the dermis, the layer of skin just below the epidermis. Second-degree burns are marked by blisters filled with clear fluid and pain.
- Third-degree burn: Also called a full-thickness burn, a third-degree burn destroys the dermis and some underlying muscle tissue or fascia. The damaged tissue is hard, purplish or white, and there is no pain because the nerve endings in the injured tissue have been destroyed. The hair on the skin is also destroyed in a third-degree burn.
- Fourth-degree burn: In this type of severe burn, the tissue may be destroyed and charred down to the bone. Grafting is necessary in order to save the affected limb.
Burns are commonplace injuries worldwide, partly because they have so many potential causes. In the United States, about one million people seek treatment for burns in hospital emergency rooms each year. This
figure actually represents a decline from the early 1960s, when the number was about two million. About 40,000 people are hospitalized for burn injuries each year rather than being treated as outpatients; of those admitted to hospitals, 60 percent, or 25,000 people, are sent to one of the 125 hospitals in the United States with specialized burn centers.
According to the American Burn Association, there are about 4,000 deaths from burns each year in the United States, 3,500 from house fires and the remaining 500 from automobile and aircraft crashes, contact with electricity, chemicals or hot liquids and substances. About 75 percent of these deaths occurred at the scene of the accident or on the way to the hospital.
Burn injuries vary according to age group:
- Infants and children: most burn injuries in children four years and younger are caused by scalds (65 percent) and contact burns (20 percent). These injuries often occur when children pull pots and pans containing hot food or boiling water from a stove top.
- Adolescents and children between the ages of four and fourteen: about 88,000 are treated in hospital emergency rooms each year. The most common causes in this age group are hair curlers, curling irons, room heaters, ovens and ranges, clothing irons, gasoline, and fireworks.
- Among adults, men are more likely to require hospitalization for burn injuries than women; 70 percent of patients admitted to specialized burn centers are male. Forty-three percent of these severe injuries occurred at the person's home; 17 percent on the street or highway; 8 percent in the workplace; and 32 percent in other locations.
Burns are caused by exposure to a source of heat, whether direct flame, electricity, radiation, contact with a hot object, or chemicals. Airway burns are caused by breathing in steam, heated air from a fire, or smoke and toxic gases.
Symptoms of first-degree burns include pain and reddening of the affected area. Second-degree burns produce blisters as well as reddened skin and pain. Third-degree burns are painless because the nerve endings in the affected area have been destroyed. The affected skin may be white or charred, and is usually dry or leathery.
The symptoms of airway burns include:
- Charred or burned mouth and lips; burns on the face or neck
- Wheezing and difficulty breathing
- Singed nose hairs or eyebrows
- Dark soot-colored mucus being coughed up
- Changed voice
The diagnosis of burns and scalds is usually obvious from the patient's situation and the appearance of the injury. Patients taken to the emergency room will usually be given a chest x ray to check for evidence of smoke inhalation or other injury to the airway.
Most of the evaluation in the hospital consists of determining the extent of the patient's injuries. The rule of nines is used to estimate the area of body surface covered by second- or third-degree burns. Another quick measurement that can be used to estimate the size of the burn is the area covered by an adult's palm, which is about 1 percent of total body area. Emergency room doctors use these rules to tell whether a patient should be sent to a specialized burn center:
- Third-degree burns covering more than 5 percent of body surface area (BSA)
- Second-degree burns covering more than 10 percent of BSA
- Any second- or third-degree burn on the face, genitals, hands, feet, or skin covering a major joint
- Burns caused by electrical currents, lightning, or chemicals
- Burns occurring together with other major injuries (head trauma, broken bones, etc.)
- Burns in patients with inhalation injuries
Minor first-degree burns can be treated at home by cooling the injured part by holding it under cool tap water for several minutes. Ice should not be used because it can make the injury to the skin worse. Butter or margarine should not be applied because oily substances will not help heal the burn and may increase the danger of infection. Aspirin or Tylenol can
be taken to ease pain, and an antibiotic ointment can be applied to the skin to reduce the risk of infection.
If a person's clothing is on fire, they should be told to “stop, drop, and roll” to put out the fire. They should be pulled away from the hot object or open flame and their clothing removed if possible. Burned clothing that is stuck to the skin should not be removed, however. The burned person should be doused with water and covered with a clean sheet or other cloth while emergency services are called. Severe burns should never be treated with ointments or other household remedies while waiting for emergency help.
Treatment of severe burns in the hospital begins with an evaluation of the patient's airway and their blood circulation. The next step is removal of burned clothing and careful inspection of the burns. After the patient's burns have been washed with sterile solution, he or she will be given intravenous fluids to prevent shock and dehydration. Painkillers are also given intravenously to relieve the patient's pain as quickly as possible.
The next step in burn treatment is surgical debridement (cutting away) of open blisters and dead tissue. If the person's burns are not severe enough to require transfer to a burn center, they will be kept in the hospital overnight to make sure that their airway has not been injured.
The prognosis of burns and scalds varies from excellent to poor depending on the location of the burn, its cause, the patient's age and overall health, and how quickly they received treatment. Minor burns rarely cause long-term complications. Second-degree burns, however, can become infected and the infection can spread into the bloodstream if not treated promptly. Patients can also become dehydrated after a burn injury. Anyone with a burn who notices red streaks or pus in the burned area, increased pain, swollen lymph nodes near the burn, or fever; or anyone who feels dizzy, lightheaded, extremely thirsty, or cannot urinate after a burn should see their doctor at once.
According to the American Burn Association, 95 percent of patients treated in specialized burn centers survive their injuries.
Prevention is one of the most important aspects of burn care, as public health doctors estimate that 75 percent of burns are preventable. The
Centers for Disease Control and Prevention (CDC) recommend the following preventive steps:
- Install smoke detectors in the home and check their batteries regularly.
- Teach small children about fire safety, including the dangers of matches and fireworks.
- Set the household water heater at 120°F (49°C) or lower to prevent accidental scalding in the tub or shower.
- Keep small children from climbing up on the stove; turn the handles of pots and frying pans toward the back of the stove to prevent children from grabbing them.
- Place fire extinguishers in key locations in the home and workplace.
- Keep electrical appliances in good repair and keep electrical cords off the floor.
- Practice fire escape routes in the home, school, and workplace.
Burns are likely to continue to be a common form of accidental injury. Better education as well as further research into burn treatment may help to lower the number of injuries and deaths caused by burns. One of the most important factors in lowering the rate in the last twenty years is the increased use of smoke detectors. A major new area of research is the development of skin substitutes for covering major burns instead of using grafts taken from the patient's own skin.
SEE ALSO Child abuse; Frostbite; Smoke inhalation; Smoking; Sunburn
WORDS TO KNOW
Debridement: The medical term for cutting away dead or damaged tissue from a burn or other injury.
Dermis: The lower layer of skin that contains blood vessels, sweat glands, and hair follicles.
Epidermis: The outermost layer of the skin.
Fascia: A sheet of connective tissue that covers and binds together the muscles, glands, blood vessels, and internal organs of the body.
Scald: A burn caused by steam or a hot liquid.
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