Thermal Burn

Thermal burns are skin injuries caused by excessive heat from contact with hot surfaces, liquids, steam, or flames, affecting approximately 450,000 people annually in the United States, with most burns being minor enough to treat at home.

Table of contents

• What is a thermal burn?
• Causes and risk factors
• How common are thermal burns?
• Symptoms
• Understanding burn severity
• First aid treatment
• When to seek medical help
• Prevention

What is a thermal burn?

A thermal burn is a type of injury that happens when your skin comes into contact with something extremely hot or extremely cold, damaging the tissues of your body. These burns involve cell damage from extreme temperatures.^[1][2]

The skin is the largest organ of the body, making up about 16% of a person’s body weight. When a thermal burn occurs, the heat causes soft tissue damage, increasing the ability of tiny blood vessels called capillaries to let fluids pass through their walls, which leads to fluid loss from the damaged area. In severe burns, the blood may become thicker and small blood clots may form.^[1][7]

Causes and risk factors

Thermal burns result from tissue exposure to an external heat source. Burns that occur at higher temperatures or for longer contact times result in deeper, more severe injuries.^[7]

There are different sources of heat that can cause thermal burns. Dry sources include fire flames, hot metal, glass, or other objects. Burns from wet sources are called scalds, which can be caused by hot water, oil, other liquids, or hot steam.^[6][1]

The main ways thermal burns happen include:^[7][4]

• Flash and flame burns occur due to direct or indirect exposure to a flame source. These require an ignition source, oxygen, and a fuel source to occur.
• Scald burns result from exposure to high-temperature liquids. Grease burns and those caused by hot oils are often much deeper than they initially appear.
• Contact burns occur from direct contact with a high-temperature object like a hot stove or iron.

You can also burn your airways if you breathe smoke, steam, or superheated air.^[6]

Several factors increase the risk of thermal burns:^[1][3]

• Young age — Children often come into contact with hot liquids. Nearly three quarters of all burn injuries suffered by young children are scalds, with most scald burns in children younger than 5 years caused by accidental spilling of hot liquids.
• Male gender — Males are at higher risk for burn injuries, mainly due to occupation-related injuries.
• Alcohol consumption — This is a common risk factor in adults who suffer burn injuries.
• Lack of smoke detectors in the home increases risk from fire-related burns.
• Certain medical conditions like epilepsy or habits like alcoholism that may cause periods where a person cannot move away from a heat source.

Burns occurring in the home account for 25% of all serious burns.^[1]

How common are thermal burns?

Thermal burns are extremely common and usually unintentional. Worldwide, about 10 million people experience burns, and about 180,000 die from them each year. In the United States, about 486,000 people receive medical care for burns each year.^[8]

Approximately 450,000 patients receive treatment for burns annually in the United States, and about 30,000 require admission to burn centers. About 86% of burns are thermal burns — 43% from fire or flame, 34% from scalds, and 9% from hot objects. Other types include electrical burns (4%), chemical burns (3%), and other types (7%).^[1]

Annually, approximately 3,400 patients die from burns or related complications such as smoke inhalation, carbon monoxide or cyanide poisoning, organ failure, or infection. Roughly 72% of these deaths occur from residential fires. Burns represent the fourth leading cause of trauma deaths and the second leading cause of accidental deaths in children ages one to four.^[1]

The good news is that the overall survival rate for all types of burns is about 97%, and deaths from burns have declined by about 75% from the 1960s.^[1]

Symptoms

Thermal burn symptoms depend on the location and the severity of the burn. They are usually worse during the first few hours or days after the burn.^[6]

Common symptoms of burns include:^[6][8]

• Pain — Burns can hurt a lot, especially when they’re in sensitive places like on your hands or face. However, full-thickness (very deep) burns may destroy nerve endings, so they may not hurt in the center of the burn.
• Blisters — Fluid-filled bumps that form on the skin.
• Swelling — The area around the burn may become puffy.
• Skin color changes — Red, white, or charred (blackened) skin.
• Peeling skin — The outer layer of skin may come off.
• Skin appearance or texture changes — The skin may become leathery and stiff in severe burns.

If you have breathed in smoke, steam, or hot air, you may have symptoms of airway burns, including:^[6]

• Burns on your head, face, neck, eyebrows, or nose hairs
• Burned lips and mouth
• Coughing
• Shortness of breath or wheezing
• Dark, black-stained mucus
• Voice changes

Understanding burn severity

The severity of a burn depends on how deep it goes into the skin. According to a theory called Jackson’s thermal wound theory, there are three zones of major burn injury:^[4]

• Zone of coagulation is the area that received maximum damage from the heat source. Cell death is certain in this area due to destruction of blood vessels.
• Zone of stasis surrounds the coagulation area, where tissue is potentially salvageable. This is the main area of focus when treating burn injuries.
• The outermost zone where tissue can recover with proper care.

Burns are classified by depth:^[8][4]

Superficial burns (similar to first-degree burns) only damage the top layer of skin called the epidermis. These are minor and cause redness and may peel. They are always self-treatable and usually heal within a couple of weeks.

Partial-thickness burns (similar to second-degree burns) go deeper, damaging the outer two layers of your skin. They can blister, cause color or texture changes more than just simple redness, and be painful.

Full-thickness burns (similar to third-degree burns) go through all skin layers and can reach all the way to the fatty tissue underneath. These burns destroy nerve endings, so the center of the burn may not hurt, although the area around it will. The skin may look leathery, charred black, or ashen and gray.

Burns can extend even deeper and damage muscles, nerves, bones, and other deep tissues. These aren’t as common, and experts sometimes call these fourth-degree burns.^[8]

Most burns are minor and can be treated as outpatients or at local hospitals. Approximately 6.5% of all burned patients receive treatment in specialized burn centers. The decision to transfer and treat at burn centers is based on the extent of body surface area burned, the depth of the burns, and individual patient characteristics such as age, other injuries, or other medical problems.^[1]

First aid treatment

The management of seriously burned patients in the first few hours can significantly affect their long-term outcome. It is important that the patient be managed properly in the early hours after injury.^[5]

For all burns, follow these immediate steps:^[10][11]

1. Stop the burning immediately — Put out the fire or stop the person’s contact with hot liquid, steam, or other material. Remove the person from the area if safe to do so.
2. Remove hot or burned clothing — Take off jewelry, belts, and tight clothing immediately, as burns can swell quickly. However, do not try to remove anything that’s stuck to the burnt skin, as this could cause more damage.
3. Cool the burn — Hold burned skin under cool (not cold) running water for at least 20 minutes as soon as possible after the injury. You can also use compresses if running water isn’t available. The water should be cool or lukewarm, maintained at temperatures ranging from 41°F to 77°F. Do not use ice, iced water, or extremely cold water, as this can cause further damage and lower body temperature dangerously.
4. Keep the person warm — Use a blanket or layers of clothing, but avoid putting them on the injured area. This will prevent hypothermia, where a person’s body temperature drops below 95°F.
5. Cover the burn — After cooling, cover the burn loosely with cling film or a sterile, non-adhesive bandage or clean cloth. Lay the cling film over the burn rather than wrapping it around a limb. A clean, clear plastic bag can be used for burns on your hand.
6. Treat the pain — Give over-the-counter pain relievers such as paracetamol (Tylenol) or ibuprofen (Advil, Motrin). Always check the manufacturer’s instructions. Children under 16 years of age should not be given aspirin.
7. Raise the affected area — If possible, lift the burned area above heart level to help reduce swelling.

For minor burns affecting only the top layer of skin, after cooling the burn, you can apply a petroleum-based ointment or first aid burn cream (non-perfumed) and a bandage. Change the bandage regularly and watch for signs of infection.^[10]

Do not use butter, oil, lotions, creams (especially if they contain fragrance), mayonnaise, mustard, honey, or toothpaste on burns. While these products may not necessarily make a burn wound worse, they may trap heat and impede healing. If they are contaminated in any way, they can lead to infection.^[10][22]

Do not pop or break burn blisters yourself. If your burns are severe enough to blister, you should be seen at a burn center where providers can properly drain the blisters and provide dressings to protect the skin underneath.^[22]

When to seek medical help

Call emergency services (911) or go to the nearest emergency room immediately if:^[6][10][11]

• The burn penetrates all layers of the skin
• The skin is leathery or charred looking, with white, brown, or black patches
• The person has symptoms of an airway burn
• The burn is on the face, neck, hands, feet, any joints, or genitals
• The burn is larger than three inches or bigger than the size of the affected person’s hand
• The person is an infant or a senior
• The person is having difficulty breathing
• The person has a head, neck, or leg injury along with the burn
• There are symptoms of shock — cold, clammy skin, sweating, rapid shallow breathing, weakness, or dizziness

You should also see a doctor if:^[10][11]

• You see signs of infection, like increased pain, redness, swelling, fever, or oozing from the burn
• The burn blister is larger than two inches or oozes
• Redness and pain last more than a few hours
• The pain gets worse with time
• There is pus oozing from the burn
• There is a change in the thickness of the burn
• There is a bad smell coming from the burn
• The person needs a tetanus shot or booster

If someone has breathed in smoke or fumes, they should also get medical attention at a hospital, as some symptoms may be delayed.^[11]

For electrical burns, always seek immediate medical attention at an emergency department, even if the burn doesn’t look serious, as they can be very damaging internally.^[11]

Prevention

Many thermal burns can be prevented by taking simple safety measures at home and in the workplace. Prevention is especially important for protecting young children and older adults who are at higher risk.^[1]

To prevent scalds from hot liquids:^[4]

• Keep hot drinks and foods away from the edges of tables and counters
• Never hold a child while holding a hot drink or cooking
• Test bath water temperature before placing a child in the bath
• Set water heaters to a safe temperature (below 120°F or 49°C)
• Turn pot handles toward the back of the stove
• Use back burners when possible

To prevent burns from fire and flames:^[1]

• Install and maintain smoke detectors in your home
• Keep matches and lighters out of reach of children
• Be careful with candles and never leave them unattended
• Use caution with fireworks
• Store gasoline and other flammable products safely
• Have a fire escape plan and practice it with your family

To prevent contact burns:

• Keep children away from hot appliances like irons, stoves, and ovens
• Use protective covers on electrical outlets
• Be careful with exhaust pipes on vehicles and equipment
• Test the temperature of objects before allowing children to touch them