Burns: degrees, risks, first aid, and treatment

Burns, also known as thermal skin injury or dermal corrosion, are caused by skin tissue damage due to excessive heat and long exposure. The medical literature refers to burns as thermal insults.

FAQ: 

What are the possible causes of burns?

What are the degrees of burns?

Besides having weeping burns, how do they manifest themselves?

What should be the first response and what does treatment look like?

The term "thermal insults" also includes the effects of cold burns, i.e. frostbite. Thermal energy can act in various forms, such as a hot fluid, touching a hot object, fire, radiation, chemical, electrical energy or explosion.

The effect of heat is either direct or indirect injury. Burn injury can be either superficial or deep that damages the deep dermis and subcutis, such as tendons or muscles. The burn acts locally, but the heat may spread to the wider area and damage the surrounding tissue.

The medical literature mentions different types of classification, i.e. dry, wet or chemical. For example, dry burns are caused by a flame, touching a hot object, or friction. Friction burn (also: abrasion or rug burn) is caused by the rapid or repeated movement of coarse rope rubbing against skin.

People are also prone to sunburn due to excessive sunbathing.

Wet burns include scalding and the action of hot steam or other hot liquids. Injuries caused by scalding very often occur in the home environment, including injuries to children.

Chemical burns include those caused by a caustic substance, such as an acid or alkali. They are called alkali burns. Aggressive substances are found at industrial sites, but also in households or in the garden. Therefore, they are not among the rare types of injuries.

Table: Burns can cause physical or chemical effects

Burns are among the most common injuries. They occur very often in childhood. In young children around the age of three to six, burn injuries are mostly bruises. Children are often exposed to burns in their homes as a result of contact with hot tea, coffee and other liquids.

During 2003–2011, 81 181 patients attended the specialised burn service for assessment and admission in England and Wales. Of these, 57 801 were admitted to the services. Source: A review of the international Burn Injury Database (iBID) for England and Wales: descriptive analysis of burn injuries 2003–2011 | BMJ Open

Older children are more likely to come into contact with flame despite parental warning. Burns caused by contact with a hot object and due to electric shock are also frequent childhood injuries.

Kex facts by WHO:

• In India, over 1 000 000 people are moderately or severely burnt every year.
• Nearly 173 000 Bangladeshi children are moderately or severely burnt every year.
• In Bangladesh, Colombia, Egypt and Pakistan, 17% of children with burns have a temporary disability and 18% have a permanent disability.
• Burns are the second most common injury in rural Nepal, accounting for 5% of disabilities.
• In 2008, over 410 000 burn injuries occurred in the United States of America, with approximately 40 000 requiring hospitalization.
• Source: Burns (who.int)

Another form of division determines the severity of the burn based on its extent. The extent of the burn is important in determining the diagnosis, especially the subsequent treatment. Wallace's Rule of Nines is used to make a rough estimate. The rule of nines divides the surface of the body by percentage. After evaluating the total percentage of damage, the severity can be determined.

The rule of nines determines the extent of burn surface area in adults:

• hea dand neck 9 %
• one arm 9 %
• one leg 2 x 9 %, or 18 %
• anterior trunk 2 x 9 % = 18 %
• posterior trunk 2 x 9 %, or 18 %
• perineum (crotch area) 1 %

In children, the rule of nines determines the percentage of bodily injury:

• head and neck 2 x 9 %
• trunk 4 x 9 %
• arms 2 x 9 %
• legs 2 x 9 %

Another typology is an estimate of the approximate size of the palm, with one palm equaling 1%.

This also applies to burns in children. Second- and third-degree burns amounting to more than 20% in adults represent serious conditions. In children, the measurement is done by age, namely:

• 0 - 3 years of age at a rate of more than 5% in case of second-degree burns
• 3 - 15 years of age more than 10 %
• and in the case of grade 3 burns, the risk is at any extent
• Burns in the face, neck, arms and legs are serious injuries in children

Table: Burns are classified according to the degree we state

A very serious group of burns is inhalation injuries as a result of airway burn. This type of burn, and others, like burns caused by electricity, i.e. high voltage, and radiation injuries are life-threatening.

So, burns are caused by severe heat that acts long enough to cause damage. Nerve endings perceive temperatures above 40 °C as an imminent danger, which is signalled by pain.

There are different causes of burns, depending on the effect of heat due to contact, fire, hot water, i.e. scalding. Corrosive substances cause caustic burns. Another group consists of burns due to electric shock or radiation.

Thermal injuries caused by hot fluids are among the most common, representing more than 60% of cases. Flame injuries are less common, i.e. about 25 percent. Skin injury on contact is about 5%, electrical burns 3%, chemical and radiation burns less than one percent.

Thermal burns and heat

Exposure to excessive heat and for a sufficiently long time will cause tissue damage. The cells die off either gradually or immediately. It depends on the temperature and the duration of the effect. The heat acts directly and spreads evenly into the surrounding tissue.

As a result, there is an inflammatory reaction (unlike a purulent skin inflammation). Small blood vessels, i.e. capillaries, will increase the transport of fluids from other blood vessels, resulting in a swelling known as a blister.

 Burns are mentioned on cave paintings dating back as many as 3,500 years.
The first written mention is fpund in the Ebers papyrus dating back to 1500 BC.
According to written records from 600 BC, the Chinese treated burns with tea decoctions.

In 1832, a French military surgeon, Baron Dupuytren, classified 6 degrees of burn severity.
The first hospital specialised in burns was established in 1843 in London.
Physician Earle was the first to suggest applying ice water to the burned area in 1879.

During World War I, Henry D. Dakin and Alexis Carrel developed a method for cleaning and disinfecting wounds.

A burn causes a local reaction or an overall response of the organism if the burned area is bigger. First, primary heat damage to the tissue occurs. As a sequel, an inflammatory reaction occurs, which has a negative effect at first. As a complication of the burn, a vascular supply disorder occurs, resulting in impaired blood flow, i.e. ischemia of the injured tissue.

Since the damaging process starts at a temperature above 45 °C, the cells die in a gradual fashion. This process takes a long time. Temperatures higher than 60 °C destroy the cell in a matter of seconds.

Table: water temperatures in scalding and time required for cell damage

The symptoms of burns are local, but if the extent of the injury is bigger, they affect the whole organism. Local first- and second-degree burns manifest as superficial injury due to the small extent of the affected body surface. If the extent is greater, the burn injury manifests itself as a generalised reaction of the whole body.

This general reaction is referred to as burn disease, sometimes as burn disorder, or burn syndrome. In adults, it affects more than 15% of the body surface. In children, over 5%. This reaction is characterised by a process that drains various substances from the site of burns, skin, and subcutaneous tissue.

Those substances are mediating compounds, such as bradykinin, histamine, prostaglandins, oxygen radicals and so on. Vascular permeability increases. The fluid passes from the vessels to the surrounding areas. It is primarily located at the site of the burn. At a later stage, it is found all over the body. This results in a systemic inflammatory response syndrome, or SIRS for short.

In turn, that results is a reduction in the efficiency of blood circulation and a reduction in blood pressure. A serious form which is a response to this large-scale burn is a burn shock. At this point, the sufferer's life and health are in danger. Prompt and professional treatment must be given.

Blood pressure values in an overview.

Larger-scale burns, i.e. during a burn syndrome, the following systemic levels will be affected:

• fluid imbalance, extravascular electrolyte and water transfer (outside the vascular system)
• metabolic disorders, accelerated metabolism, increased energy requirements and oxygen consumption
• vital organ function, i.e. risk of renal, gastrointestinal (ileus) failure, respiratory failure, and risk of Multiple Organ Dysfunction Syndrome (MODS)
• bacterial infection of damaged tissue is a gateway for the entry of bacteria and other microorganisms, the consequent risk of septic shock

A brief overview of burn symptoms:

• redness, first-degree burns
• swelling, local at the site of the burn and without blisters, i.e. first-degree burns
• pain, in first- and second-degree burns
• blisters, in second-degree burns
• necrosis of the skin and tissues appears white, brownish to black in colour, third-degree burns
• disruption of the skin's sensation, affected tissues do not hurt
• charred skin, black eschars, fourth-degree burns

The condition is severe if the heat affects the face and chest areas. In this case, there is a high risk of airway damage, and therefore inhalation injury or airway burn. This occurs when inhaling hot air, flames, steam, smoke, or products of combustion.

In case of airway burns, the upper airways are most often affected. Burns in this area are dangerous due to swelling. The swelling can partially or completely block the airways, causing suffocation. Damage to the lower respiratory tract is usually due to the inhalation of hot steam.

Lung damage usually occurs as a result of inhaling particles generated due to combustion. Inhalation results in a complex chemical reaction that results in respiratory failure. It is manifested by difficulty breathing, and later on by pulmonary edema. Respiratory failure can evolve for hours to days.

Inhalation burn presents with the following symptoms:

• cough
• stridor
• coughing up mucus containing combustion particles, soot
• difficulty breathing, respiratory arrest
• pulmonary edema even 24 hours after the event
• vomiting

Beware of burn complications

A burn is a superficial injury to the skin. Of course, in the case of first-geade burns, there is no risk of deteriorating health unless the size of the affected area is large. The issues subside and heal within a few days. However, the situation changes in cases of more severe thermal injuries.

Serious complications of burns:

• shock, systemic inflammatory response syndrome
  • respiratory failure, pulmonary edema
  • heart failure
  • brain swelling
  • renal failure
  • gastrointestinal failure (ileus) and gastrointestinal bleeding
• infection to septic shock (colloquially, blood poisoning)
• loss of shape and function of the tissue that heals with the scar
• the development of contractures, such as muscle shortening

Diagnosis is mainly based on medical history, i.e. the patient's subjective description. The condition of the affected area is evaluated by sight. The skin is red, it has blisters. The blisters will appear within minutes. Next, it is important to assess the degree and extent of burns and continue with treatment.

In the event of a caustic burn, the clinical picture includes, for example, pain assessment. Pain is usually felt as a burning sensation, drinking a corrosive substance creates a burning sensation in the mouth, the lips change colour, and the sufferer has stomach pain. When hitting the eye, the possibility of opening the eyelids, eye pain, but also cramps of the eye muscles.

The following actors are considered when evaluating burns:

• age
• the health status of the affected person and primary diseases, especially in the elderly
• the affected site
• cause
• extent, depth and degree
• body temperature (assumed)
• first aid provided 
• associated injuries, such as wounds, head injury, chest injury, abdominal injury
• intoxication (alcohol, medication)

Examinations for minor burns are usually performed by a GP, sometimes a surgeon or a traumatologist. In more serious situations, the victim is usually hospitalised in the intensive care unit or burn centre, depending on the condition.

The following is used for rapid evaluation at the initial examination:

• minor burns - less than 15% in adults and less than 10% in children
• extensive burns in adults - more than 15% and in children more than 10%

A physical examination and evaluation of basic vital functions are performed. Mental state, respiration and blood circulation are assessed. The victim may remain fully conscious, with orientation intact, or have psychological effects.

Breathing is assessed in terms of whether it is spontaneous, unobstructed, or laboured. Stridor, cough, coughing up mucus may be present. Respiratory rate may be accelerated. If inhalation trauma is suspected, an X-ray or CT of the lungs is also performed.

Blood circulation is also subjected to a comprehensive evaluation. Blood pressure and pulse rate, which reflect heart activity, are measured. Low pressure, i.e. hypotension, fast pulse, i.e. tachycardia, weak or impalpable pulse, and worsened blood flow to the periphery (distal or end parts of the body), are all signs of a burn shock.

Professional examination is necessary for the following types of burns:

• deep burns
• burns 
  • on the face, mouth, nose, ears
  • shoulder
  • chest, trunk
  • extensive lower limb burns
  • genitals
• second-degree burns larger than the palm
• all burns greater than 5% of the body surface, including superficial
• burn in a child
• impossibility or inability to assess the condition of the burn

Burns are damage to the skin or mucous membranes and deeper structures due to excessive heat. This heat must be applied long enough, and the extent of the damage also depends on the temperature.

The first reaction to high temperature is pain. The skin turns red in a few seconds. Swelling occurs immediately afterwards. In case of a second-degree burn, blisters form within a few minutes, about 10 minutes.

The top layer is destroyed first. Mediators are exiting the body, which triggers a reaction. These mediators have a negative effect on blood vessels which are now more permeable. Intravascular fluid is transferred from the vessels. There is a swelling that is only local with small burns.

However, if the extent of the burn is larger, a systemic reaction, swelling, and capillary leakage may occur. At the same time, the blood pressure is reduced. The risk of shock is more than 15% in adults and more than 10% in children.

Burn shock worsens the overall stress due to thermal injury, pain, capillary leakage, and reduced tissue oxygenation. The shock is life-threatening. In particular, there is a risk of multiorgan failure, or inhalation trauma which is just as severe a condition.

Even in the case of a minor burn, immediate first aid is of utmost importance. Of course, this is all the more important when a more serious injury occurs. First aid is also important in terms of subsequent treatment and overall health.