Conditions · Surgery and trauma
Burns (thermal, chemical, electrical; inhalation injury) !
A burn is skin and tissue damage from heat, chemicals, electricity or radiation. Large or deep burns cause shock and need specialised care.
Updated 2026-11-01
Structures involved
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Why it happens
- Patterns of necrosis: coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous
- Thermal injury: burns, hyperthermia and hypothermia
- Mechanical and electrical injury: abrasion, contusion, laceration, wounds
- Vascular changes in acute inflammation: vasodilation, leakage, exudate vs transudate
- Healing of skin wounds: first and second intention
- Causes of cell injury
Show 10 more
- Tissue repair: regeneration or scar; labile, stable and permanent cells
- Abnormal repair: chronic wounds, hypertrophic scar, keloid, contracture
- Disseminated intravascular coagulation: how consumption causes both clots and bleeding
- Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer
- Shock: types, stages and the organs it damages
- Precancerous conditions: when chronic inflammation, metaplasia or hyperplasia raise the risk
- Starling forces at the capillary
- Fluid shifts between compartments
- Carbon monoxide, methemoglobin and cyanide
- Skin: epidermis layers, dermis, hypodermis
What it is
Tissue injury caused by heat (flames, scalds, contact), chemicals, electric current or radiation. Severity depends on the depth, the percentage of total body surface area (TBSA) burned, the site and associated inhalation injury.
Who gets it
Burns cause well over a hundred thousand deaths a year worldwide, most in low- and middle-income countries, and far more people are left with scars and disability. Scalds in young children at home, cooking fires and work-related electrical and chemical burns are common patterns in Latin America; fireworks burns peak in Colombia during the December holidays.
Causes
- Thermal: flames, scalds from hot liquids, contact with hot objects
- Chemical: acids and alkalis (alkalis penetrate deeper)
- Electrical: low- and high-voltage current, lightning
- Radiation, including sunburn
- Inhalation of hot gases and smoke in enclosed-space fires
Risk factors
- Young children and older adults
- Open-fire cooking and unsafe household fuel
- Fireworks and gunpowder
- Work with electricity or industrial chemicals
- Epilepsy, alcohol use and reduced mobility
Pathophysiology
Heat causes coagulation necrosis at the centre of the wound, surrounded by a zone of stasis that can be saved or lost depending on resuscitation, and an outer zone of hyperaemia. Large burns release inflammatory mediators that make capillaries leak throughout the body, producing hypovolaemic (burn) shock, oedema and later a hypermetabolic state. Smoke inhalation injures the upper airway by heat and the lower airways chemically, and carbon monoxide and cyanide cause tissue hypoxia.
Classification
- Superficial (first degree): epidermis only, red and painful, no blisters
- Superficial partial thickness: blisters, moist, very painful, blanches
- Deep partial thickness: into the deep dermis, less painful, may need grafting
- Full thickness (third degree): white, leathery or charred, painless
- Extent by rule of nines in adults (Lund–Browder chart in children; the patient's palm is about 1% TBSA)
Symptoms and signs
- Red, blistered, white or charred skin depending on depth
- Pain, which may be absent in full-thickness areas
- Swelling of the burned area
- Hoarseness, cough, soot in the mouth or nose and singed facial hair after a fire in a closed space
- Entry and exit wounds and possible arrhythmia after an electrical injury
Diagnosis
- Clinical
- ABCDE assessment first, with special attention to the airway, then depth and %TBSA (only partial- and full-thickness burns count). Look for circumferential burns, associated trauma and, in children, signs of maltreatment. Criteria such as extent, site, depth, inhalation and electrical injury decide referral to a burn unit.
- Tests
- Arterial blood gas with carboxyhaemoglobin and lactate (cyanide suspected when lactate is very high), electrolytes, creatinine, creatine kinase and urine myoglobin in electrical or deep burns, blood count, group and crossmatch, and an ECG after electrical injury.
- Imaging
- Chest X-ray as a baseline; flexible bronchoscopy confirms inhalation injury. Other imaging only for associated trauma.
Differential diagnosis
- Toxic epidermal necrolysis and Stevens–Johnson syndrome
- Staphylococcal scalded skin syndrome in children
- Necrotising soft-tissue infection
- Frostbite and other cold injuries
Goal of treatment
Stop the burning process, secure the airway, restore circulating volume while avoiding over-resuscitation, prevent infection and hypothermia, and close the wound early to preserve function and appearance.
Treatment
- Acute
- First aid: stop the burning, remove clothing and jewellery, cool with clean running water for several minutes (not ice) and cover with a clean dressing; prolonged irrigation for chemical burns.
- Acute
- Early intubation when inhalation injury threatens the airway, and high-flow oxygen when carbon monoxide poisoning is suspected.
- Medical
- Fluid resuscitation with crystalloids (usually Ringer's lactate) for major burns, estimated by weight and %TBSA with formulas such as Parkland, half in the first eight hours from the time of the burn, and adjusted to urine output.
- Procedure
- Escharotomy for circumferential full-thickness burns that compromise limb circulation or chest movement.
- Surgical
- Early excision of deep burns and skin grafting, done in a burn unit.
- Follow-up
- Nursing priorities: airway, hourly urine output through a catheter, vital signs and temperature, pain control, tetanus status, wound care with topical antimicrobials, nutrition and infection surveillance.
- Rehabilitation
- Physiotherapy, splints and pressure garments to prevent contractures and hypertrophic scars, and psychological support.
Drugs for this condition
Complications
- Burn shock and acute kidney injury
- Wound infection and sepsis, the main later cause of death
- Inhalation injury, pneumonia and ARDS
- Carbon monoxide and cyanide poisoning
- Compartment syndrome and rhabdomyolysis
- Hypertrophic scars, contractures and disability
- Curling stress ulcer and hypermetabolic state
Prognosis
Mortality rises with age, %TBSA and inhalation injury. Small superficial burns heal without scarring, whereas deep and extensive burns need grafting and long rehabilitation; specialised burn care has greatly improved survival.
Prevention
- Safe cooking practices and keeping children away from hot liquids and stoves
- Smoke alarms and safe storage of flammable substances
- Banning or regulating gunpowder and fireworks use
- Electrical safety at home and at work
- First-aid education: cool running water
Test yourself
Think of the answer, then tap the question to see it.
How is the burned body surface area estimated in adults?
With the rule of nines (head and each arm about 9%, each leg and the front and back of the trunk about 18% each, perineum 1%); the Lund–Browder chart is used in children.
Which burn depth is painless, white or leathery and needs grafting?
Full-thickness (third-degree) burn, because nerve endings in the dermis are destroyed.
Which formula is classically used to estimate fluid needs in the first 24 hours of a major burn, and how is it timed?
The Parkland formula (crystalloid based on weight and %TBSA), giving half in the first eight hours from the time of the burn and titrating to urine output.
Which findings suggest inhalation injury after a fire in a closed space?
Facial burns, singed nasal hair, soot in the mouth, carbonaceous sputum, hoarseness or stridor; they call for early airway control.
What is an escharotomy and when is it needed?
An incision through burned eschar to release a circumferential full-thickness burn that is cutting off limb blood flow or restricting chest movement.
Related conditions
- Carbon monoxide poisoning
- Cyanide poisoning
- Acute compartment syndrome
- Hypovolaemic shock
- Sepsis and septic shock
- Acute respiratory distress syndrome (ARDS)
- Acute kidney injury
- Major trauma (polytrauma): ATLS primary survey
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Burns (World Health Organization, 2026); Burns (MedlinePlus (U.S. National Library of Medicine), 2024).
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