The danger of fire

What is a burn and what causes are there?

A burn is a damage to the skin caused by excessive heat exposure. Heat damages or destroys tissue, whether the injury is a burn or a scald. Depending on how long and how intense the heat exposure is, different types of skin damage occur. 

Burns are most commonly caused by flames. Next come scalds, chemical agents, sun exposure or electric shocks. A scald occurs when hot liquid or hot steam comes into contact with the skin – for example boiling water, very hot tea or coffee, or hot frying oil.

How are burns classified by severity?

Burns are classified into four degrees according to their depth. First-degree: the skin reddens, but the injury is superficial and limited to the outermost skin layer (epidermis). The burn is painful but the skin heals completely. 

Second-degree: the burn reaches the second skin layer, the dermis, and blistering occurs. The blister serves a protective function: fluid forms between the affected skin layers and cools the wound under the blister. A further distinction is made between 2a and 2b. In 2a the wound bed is pink and hairs are still firmly attached. In 2b the wound bed is necrotic and white, and hairs are easily removed. Pain is reduced due to damage to local pain fibres. From burn degree 2b onwards, long-term consequences can occur: tissue destruction and cell death prevent skin regeneration and scars form. Surgical treatment may be necessary.

Third-degree: the two upper layers of the skin are destroyed and the third layer (subcutis) is damaged. The skin hangs in shreds and whitish tissue lesions are visible. Usually the burnt skin is removed surgically and skin is transplanted from another site. 

Fourth-degree: the skin is charred and black, muscles, tendons and joints are damaged. These burns are usually associated with further complications and require hospital treatment.

What symptoms occur with burns?

Burn changes are divided into three zones: coagulation zone (core of the thermal injury), stasis zone (zone around the core with impaired cell functions) and hyperaemic zone (where local compensatory mechanisms lead to hyperaemia and heat dissipation). 

Depending on the duration and intensity of the heat exposure, different symptoms occur with a burn. Being burned means: reddened, scaly skin, blisters, swelling and white or black charred skin. 

Mild burns are painful. In severe burns the sensation of pain is disturbed due to destruction of the nerve endings and acute pain is usually absent or minimal. 

How is the percentage area of burns calculated?

Two criteria are used to assess severity: the depth of the burn and the extent of the affected body surface area. In adults the rule of nines is useful for estimation. According to this rule, head and neck account for 9%, each arm 9%, the whole trunk 36%, each leg 18% and the genitals 1% of the body surface. The more skin that is affected, the more dangerous the burn.

What complications can occur with severe burns?

Depending on the depth and extent of the burn, not only local reactions can occur but also systemic reactions, e.g. a circulatory shock and an inflammatory whole-body reaction – burn disease. 

In the worst case this is accompanied by a loss of organ function in organs that were not initially affected (e.g. acute kidney failure). In addition, severe burns weaken the immune system, increasing the risk of wound infection.

Burned – what now? Top first-aid tips at a glance

• From second-degree burns onwards, see a doctor. Emergency services must be called if burns are severe and extensive. This also applies if smoke has been inhaled or if sensitive areas such as the head, face, hands or genitals are affected.
• For minor burns and scalds, carefully remove clothing and jewellery from the affected skin areas as they can otherwise act as heat reservoirs. If clothing is stuck to the skin, cut it away carefully around the area.
• Cool the affected area immediately after the burn for five to ten minutes or until pain no longer occurs after stopping the cooling. Tepid tap water is best. Prolonged cooling has not been shown to significantly reduce skin damage and may reduce blood circulation and thus worsen the injury. Never apply ice or cold packs to the burn wound as they can further damage tissue.
• Do not cool extensive burns. There is a risk of hypothermia. Rule of thumb: only cool if the burned body surface is at most five percent — which corresponds approximately to the forearm area in adults. For children, only cool the arms and legs, not the trunk. Do not cool unconscious persons, newborns and infants as they become hypothermic very quickly.
• Avoid home remedies such as powder, flour, raw potato, baking soda, banana peels, honey, oils and the like. They can contaminate the wound and cause infection and partly prevent cooling of the wound.
• Special hydroactive wound dressings prevent the wound from drying out and can remain on the skin for days. As hydrogels they have a mild cooling effect. Hydroactive dressings are fixed with adhesive tape or a gauze compress.
• For severe scalds remove clothing immediately; for severe burns clothing should be left on the body because removing it can cause further injury. Call emergency number 144. If available, cover wounds with a sterile burn or wound dressing and secure with a loose bandage. Open wounds are particularly prone to infection. If no sterile dressing is available, do not cover the burn wound with a bandage.
• For trunk burns and other large-area burns, the wound is covered with a metallised foil. Metallised foils are sterile sheets coated with a vapour-deposited aluminium layer and do not stick to the wound.
• Do not puncture burn blisters, as this can allow germs to enter and lead to infection and inflammation of the skin. If the blister is very large and at risk of bursting due to high tension or if redness and swelling occur indicating infection, a doctor should be consulted. There the blister will be opened under sterile conditions.
• Signs of a life-threatening shock are paleness, trembling, restlessness and cold sweat. Keep the person warm, talk to them. Lay the legs slightly elevated so blood can flow to vital organs. In sudden loss of consciousness check responsiveness and breathing. If breathing is normal, place the person in the recovery position. If there is no breathing, start resuscitation immediately (30 chest compressions, 2 rescue breaths). Continue until the emergency services arrive or the person shows signs of life.

Fortunately many burns are harmless and can be treated at home!