Thermal injury to skin classified by depth (superficial / partial / full) and TBSA; severity determines fluid resuscitation and disposition.
Also known as: burns, thermal burn, first degree, second degree, third degree, scald, flame burn
Overview
Tissue injury caused by exposure to heat (flame, scald, contact, flash, friction). Burns are classified by depth (superficial / superficial partial-thickness / deep partial-thickness / full-thickness / subdermal) and by total body surface area (TBSA) involved. Severity dictates fluid resuscitation, transfer to burn center, and long-term outcomes.
Epidemiology
~500,000 US burn injuries annually receiving medical treatment; ~40,000 hospitalizations; ~3,000 fire-related deaths. Scalds are most common in young children; flame burns in adults. Bimodal age peaks (young children and elderly).
Try two board-style Burns questions
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Question 1DermatologyMedium
A 62-year-old man presents with a non-healing ulcer on his lateral calf. Thirty years ago he sustained a deep flame burn to that leg that healed with a thick, contracted scar. Over the past 4 months a firm nodule developed within the old scar, then broke down into a chronic ulcer with raised, everted margins that bleeds with minor trauma and has not responded to topical antibiotics or dressings. He has no fever, and the surrounding skin is not warm or erythematous. Which of the following complications is this lesion most likely to represent?
ASquamous cell carcinoma
BNodular basal cell cancer
CChronic venous leg ulcer
DPyogenic granuloma nodule
EPyoderma gangrenosum ulcer
Reveal answer & full explanation
Correct answer: A — Squamous cell carcinoma
ASquamous cell carcinoma✓
BNodular basal cell cancer
CChronic venous leg ulcer
DPyogenic granuloma nodule
EPyoderma gangrenosum ulcer
Why Squamous cell carcinoma is correct
A Marjolin ulcer is an aggressive squamous cell carcinoma that arises in a chronic burn scar or other chronically inflamed, non-healing wound, classically decades after the original injury.
The hallmark presentation is a new nodule or non-healing ulcer with raised, everted margins developing in long-standing scar tissue that fails routine wound care, exactly as described here.
Any chronic burn-scar wound that will not heal warrants biopsy to exclude malignant transformation; Marjolin ulcers metastasize more readily than typical cutaneous squamous cell carcinoma.
Why the others are wrong
Nodular basal cell cancer is the most common skin cancer overall, but it favors chronically sun-exposed skin and forms a pearly, telangiectatic papule; it is not the malignancy characteristically arising within old burn scars.
Pyoderma gangrenosum ulcer is a neutrophilic ulcer with violaceous, undermined (not everted) borders, associated with inflammatory bowel disease and pathergy; it is not a recognized late complication of a healed thermal burn.
Chronic venous leg ulcer occurs over the medial malleolus or gaiter area in patients with venous insufficiency, with sloping irregular borders, edema, and hyperpigmentation, rather than a firm nodule with heaped-up everted edges arising in scar tissue.
Pyogenic granuloma nodule — bleeding with minor trauma is its hallmark, and it can follow local injury, but a pyogenic granuloma is a soft, friable red vascular papule that grows rapidly over weeks; it does not form a firm, chronic ulcer with raised, everted margins arising in decades-old burn-scar tissue.
Question 2DermatologyEasy
A 14-month-old boy is brought to the emergency department after pulling a cup of freshly brewed coffee off a kitchen counter onto his chest and arm. On examination he has pink, moist, blistered areas that are very painful and blanch with pressure, covering roughly 6% of his total body surface area. The injury follows an irregular splash pattern with run-off across the flexor creases, consistent with the reported mechanism. His mother asks why young children like him are especially prone to this kind of injury. Which of the following is the strongest risk factor for burn injury in this age group?
AUnsupervised access to fireworks
BContact with a hot clothing iron
CAccess to spilled hot liquids
DChewing on electrical cords
EExposure to a residential house fire
Reveal answer & full explanation
Correct answer: C — Access to spilled hot liquids
AUnsupervised access to fireworks
BContact with a hot clothing iron
CAccess to spilled hot liquids✓
DChewing on electrical cords
EExposure to a residential house fire
Why Access to spilled hot liquids is correct
Scalds from hot liquids are the single most common cause of thermal burns in young children, driven by curiosity, short stature that places them at counter and stovetop level, and the ability to grab cups, pot handles, and tablecloths.
Unsafe water-heater settings (>120F) and unsupervised access to stoves, ovens, candles, and fireworks add risk, but spilled or pulled-down hot liquids account for the majority of pediatric burns and fit this child's irregular splash pattern and partial-thickness depth.
An accidental scald produces an irregular splash distribution with run-off across the flexor creases; by contrast, a stocking-glove immersion pattern with sharp lines and sparing of the flexor creases would raise concern for inflicted (abuse) burns and mandate reporting.
Why the others are wrong
Contact with a hot clothing iron — Contact burns from irons, stovetops, and oven doors are the second most common burn mechanism in toddlers but are far less frequent than scalds; they leave a sharply demarcated burn in the shape of the hot object, and a patterned iron-shaped burn should also prompt evaluation for inflicted injury.
Chewing on electrical cords — Mouthing a live cord or extension-cord junction causes oral commissure burns from electrical arcing in toddlers, but electrical injuries account for only a small fraction of pediatric burns and injure the lips rather than producing a chest-and-arm splash pattern.
Unsupervised access to fireworks — Fireworks cause flame and blast burns mainly in older children, adolescents, and young adults around holidays; they are an uncommon cause of burns in a 14-month-old compared with hot-liquid scalds.
Exposure to a residential house fire — house fires are the leading cause of burn-related deaths in children, which makes this tempting, but they are a far less common cause of burn injury than scalds in toddlers, who are burned mostly by hot liquids at home; flame burns become relatively more common in older children.
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Heat denatures proteins, disrupts cell membranes, and triggers inflammatory cascade. Jackson's burn zones: (1) zone of coagulation (irreversible necrosis at center), (2) zone of stasis (potentially salvageable with resuscitation), (3) zone of hyperemia (peripheral vasodilation, fully reversible). Large burns (>20% TBSA) cause systemic inflammatory response with capillary leak → massive fluid shifts → hypovolemia and shock if not resuscitated; hypermetabolic state lasting months.
Clinical presentation
Symptoms
Pain (intact in partial-thickness; ABSENT in full-thickness — neural destruction)
Dyspnea, hoarseness, stridor, soot in nares/mouth — suspect airway burn
Anxiety, agitation
Loss of consciousness or carbon monoxide poisoning symptoms (headache, confusion, cherry-red skin — late finding)
Signs / physical exam
Superficial (first-degree): erythema, dry, painful, blanches; epidermis only; e.g., sunburn; heals in 3-7 days without scarring; NOT counted in TBSA
Superficial partial-thickness (second-degree): pink-red, MOIST, BLISTERS, very painful, blanches; epidermis + papillary dermis; heals in 7-21 days with minimal scarring
Deep partial-thickness (second-degree): mottled red/white, drier, less blanching, decreased pinprick sensation, often blistered; epidermis + deep dermis; heals in 3-8 weeks with scarring, often needs grafting
Full-thickness (third-degree): white, leathery, charred, or waxy; DRY, INSENSATE, non-blanching, may show thrombosed vessels; involves full dermis; requires grafting; scarring inevitable
Subdermal (fourth-degree): extends into fat, muscle, bone; charred, may have eschar; reconstructive surgery, amputation
Calculate TBSA — Rule of Nines (adult): head 9%, each arm 9%, each leg 18%, anterior trunk 18%, posterior trunk 18%, perineum 1%. Children: head 18%, each leg 14% (modified). Patient's palm = ~1% TBSA — useful for scattered burns. ONLY partial- and full-thickness count; superficial burns excluded.
Clinical depth assessment + TBSA calculation. Major burn (American Burn Association burn center transfer criteria): partial-thickness >10% TBSA; any full-thickness; face/hands/feet/genitalia/major joints/perineum; electrical/chemical/inhalation injury; comorbidities; pediatric burns at non-pediatric centers; concomitant trauma.
Labs
All major burns: CBC, BMP, glucose, lactate, ABG with carboxyhemoglobin (suspect CO poisoning), cyanide level if industrial/structure fire, troponin (electrical burns), CK (rhabdomyolysis), urinalysis (myoglobinuria), type and cross
Give 100% O2 empirically to all suspected CO poisoning (COHb correlates poorly with symptoms); consider hyperbaric O2 for COHb >25%, neurologic/cardiac involvement, syncope, or pregnancy
Cyanide poisoning → hydroxocobalamin
Wound cultures for delayed presentation or signs of infection
Imaging
Chest X-ray (baseline + 24-48 h for inhalation injury progression)
CT brain if altered mental status, trauma history
Bronchoscopy if inhalation injury suspected — gold standard for diagnosis
Imaging for associated trauma (fall from height, MVC)
Diagnostic algorithm
Depth
Skin Layers
Appearance
Sensation
Healing
Superficial (1st°)
Epidermis
Erythema, dry, blanches (sunburn)
Painful
3-7 d, no scar; NOT counted in TBSA
Superficial partial (2nd°)
Epidermis + papillary dermis
Pink, moist, blisters, blanches
Very painful
1-3 wk, minimal scar
Deep partial (2nd°)
Epidermis + deep dermis
Mottled red/white, drier, less blanch
Decreased pinprick
3-8 wk, scarring; often graft
Full thickness (3rd°)
Full dermis
White/leathery/charred, DRY, non-blanching
INSENSATE
Requires grafting; scar inevitable
Subdermal (4th°)
Fat, muscle, bone
Charred, eschar
Insensate
Reconstruction or amputation
Burn depth classification — appearance, sensation, and healing potential.
Treatment
First-line
Initial management — ATLS approach: Airway (low threshold to intubate before edema; cuffed tube), Breathing (100% oxygen, manage inhalation injury), Circulation (large-bore IV access; avoid burned skin if possible), Disability, Exposure (remove clothing/jewelry, prevent hypothermia)
Stop the burning process: cool with room-temperature water 10-20 min (do NOT use ice → tissue injury, hypothermia); remove smoldering clothing and jewelry
Fluid resuscitation for >20% TBSA partial/full-thickness burn (adult) or >10% (child):
• Parkland formula: 4 mL × kg × %TBSA Lactated Ringer's over first 24 hours; ½ over first 8 hours from time of injury, ½ over next 16 hours (the classic exam formula; current ABLS starts adults at 2 mL × kg × %TBSA, children at 3 mL plus maintenance dextrose if <30 kg, and electrical injury at 4 mL, then titrates to urine output)
Monitor for compartment syndrome (extremity, chest, abdomen)
Escharotomy (longitudinal incision through full-thickness eschar along the medial and lateral mid-axial lines) at bedside or OR — indicated for a circumferential full-thickness burn with distal vascular compromise (loss of Doppler pulses, cool pale limb, delayed capillary refill, worsening pain or paresthesias) or chest-wall eschar impairing ventilation; expected resuscitation edema or an elevated CK alone is not an indication
Fasciotomy if compartment pressures elevated
Definitive coverage
Early excision and split-thickness skin grafting for deep partial-thickness and full-thickness burns (typically within 1 week)
Allograft or biologic skin substitutes (Integra) for large burns lacking donor sites
Cultured epidermal autograft for massive burns
Second-line / adjunct
Rehabilitation: physical/occupational therapy from day 1 — splinting, positioning, range-of-motion to prevent contracture
Superficial (first-degree) burns are NOT counted in TBSA for resuscitation calculations.
Full-thickness burns are PAINLESS due to neural destruction; intense pain suggests partial-thickness — counterintuitive at the bedside.
Parkland formula = 4 mL × kg × %TBSA Lactated Ringer's over first 24 h, half in first 8 h; titrate to urine output, NOT formula.
Suspect inhalation injury with facial burns, singed nasal hair, carbonaceous sputum, hoarseness — intubate EARLY before airway edema makes it impossible.
References
ABA 2024 — American Burn Association Practice Guidelines and Burn Center Referral Criteria
ABLS / ATLS — Advanced Burn Life Support Course (ABA) and Advanced Trauma Life Support (ACS-COT)
ISBI 2016 — ISBI Practice Guidelines Committee (Steering and Advisory Subcommittees). ISBI Practice Guidelines for Burn Care. Burns 2016;42(5):953-1021
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