Surgery chapters
Burns: area and depth in adults and children, criteria for transfer to a burns unit
How to measure the size of a burn (rule of nines, palm method, Lund and Browder chart) in adults and children, how to judge burn depth, and which patients need a specialist burns unit.
- Burn size is expressed as % TBSA: use the patient's whole hand = 1% for small burns, the rule of nines for a quick adult estimate and the Lund and Browder chart for children and accuracy.
- Simple erythema is not counted. Depth runs from epidermal to superficial partial, deep partial and full thickness, judged by blistering, colour, blanching and pinprick sensation.
- Refer to a burns unit for large burns, inhalation injury, special areas (face, hands, feet, perineum, joints), full-thickness, electrical and chemical burns, extremes of age and suspected abuse.
On this page
Overview
Two numbers decide how serious a burn is: its area (as a percentage of total body surface area, % TBSA) and its depth. The third major factor is inhalation injury. Area drives fluid needs; depth decides whether the wound will heal by itself or needs surgery. These assessments also decide whether the patient should go to a specialist burns unit.
Assessing burn area
Rules
- Assess in a warm room with the whole patient exposed (log-roll to see the back), after washing off soot. Avoid hypothermia.
- Count partial-thickness and full-thickness burns only.
- Do not count simple erythema (epidermal or "first-degree" burn, like sunburn).
Methods
| Method | Use |
|---|---|
| Patient's hand (palm with fingers closed) = about 1% TBSA | Small or patchy burns |
| Rule of nines (Wallace) | Quick estimate in adults, prehospital and emergency room |
| Lund and Browder chart | Most accurate; allows for age; best for children and larger burns |
The patient's own hand, including the fingers, is about 1% of their body surface. Use the patient's hand, not the examiner's.
Rule of nines in adults
| Region | % TBSA |
|---|---|
| Head and neck | 9 |
| Each upper limb | 9 (two = 18) |
| Front of trunk | 18 |
| Back of trunk | 18 |
| Each lower limb | 18 (two = 36) |
| Perineum and genitalia | 1 |
| Total | 100 |
A man has burns of the whole front of the trunk, the whole right arm and the front of the left leg. A patch of red, unblistered skin on the face is ignored.
Front of trunk 18 + right arm 9 + front of left leg (half of 18) 9 = 36% TBSA
Children: why the rule changes
A young child has a relatively larger head and smaller legs than an adult. Using the adult rule overestimates leg burns and underestimates head burns.
| Region | Infant / young child (paediatric rule) | Adult |
|---|---|---|
| Head and neck | 18% | 9% |
| Each upper limb | 9% | 9% |
| Front of trunk | 18% | 18% |
| Back of trunk | 18% | 18% |
| Each lower limb | 14% | 18% |
On the Lund and Browder chart, the head share falls and the thigh and leg shares rise steadily with age until adult proportions are reached in the teens. This is why the chart is preferred for children.
A toddler pulls a pot of hot water over himself and scalds the whole head and neck and the whole front of the trunk.
Paediatric values: head and neck 18 + front of trunk 18 = 36% TBSA
Using the adult rule (9 + 18 = 27%) would underestimate the burn.
In children, the head is 18% and each leg is 14%. A question asking for "rule of nines in an infant" expects these values, not the adult 9% and 18%.
Assessing burn depth
Clues from the history
- Burn damage depends on temperature and time of contact.
- Scalds in older children and adults are usually superficial (deeper in infants and without good first aid).
- Hot fat, flame and contact burns are often deep.
- Electrical contact burns are full thickness.
- Alkali (including cement) is often deep; strong acids can be deep.
Classification
| Depth (old name) | Layers damaged | Appearance | Blanching / capillary refill | Sensation | Healing |
|---|---|---|---|---|---|
| Epidermal (first degree) | Epidermis only | Red, dry, no blisters | Blanches | Painful | Few days; not counted in TBSA |
| Superficial partial thickness (superficial dermal) | Epidermis and papillary dermis | Blisters, pink, moist | Blanches, brisk refill | Very painful, pinprick normal | About 2 weeks, little or no scar |
| Deep partial thickness (deep dermal) | Into the reticular dermis | Drier, red or mottled; fixed capillary staining | Does not blanch | Reduced; cannot tell sharp from blunt | 3 weeks or more; usually hypertrophic scarring; often needs surgery |
| Full thickness (third degree) | Whole dermis | White, waxy, brown or black; hard and leathery; thrombosed veins | No capillary return | Painless (nerve endings destroyed) | Does not heal except from the edges; needs excision and grafting |
The bedside tests are capillary refill (blanching) and pinprick sensation. Painful and blanching means superficial; insensate, leathery and non-blanching means full thickness.
Burns that look superficial on day 1 can deepen over 48 hours (especially scalds). Reassess any burn of uncertain depth after about 48 hours before deciding on surgery.
The deeper the burn, the less it hurts: painful = superficial, painless = full thickness.
Factors that make a burn more serious
- Larger % TBSA.
- Inhalation injury (doubles mortality).
- Deep burns.
- Extremes of age, pre-existing disease, associated trauma.
- Circumferential burns of a limb or chest.
Criteria for transfer to a specialist burns unit
Not every burn needs a burns unit. The usual criteria combine Bailey & Love (UK practice) and ATLS (American Burn Association list):
| Category | Examples |
|---|---|
| Size | Partial-thickness burns over 10% TBSA (ATLS); any burn likely to need IV fluid resuscitation |
| Depth | Full-thickness burns in any age group; any burn likely to need surgery |
| Special areas | Face, hands, feet, genitals and perineum, and burns over major joints |
| Airway | Suspected airway or inhalation injury |
| Type | Electrical burns (including lightning) and chemical burns (e.g. concentrated hydrofluoric acid) |
| Patient | Extremes of age; pre-existing illness (diabetes, renal failure); burns with major trauma |
| Social | Suspected non-accidental injury; psychiatric or social reasons not to send home; children in hospitals without paediatric facilities |
Burns to the face, hands, feet, perineum and joints need specialist care even if small, because scarring there causes major loss of function.
Before transfer:
- Secure the airway if inhalation injury is suspected and transport will be long (intubate before transfer).
- Start fluids and a urinary catheter for large burns.
- Cover wounds with clean dressings or cling film.
- Send a written record of burn area, fluids given and urine output.
- Discuss with the receiving unit first.
Recognising non-accidental burns
- Story does not match the injury, or delay in seeking help.
- Sharp-edged, symmetrical immersion scalds ("glove and stocking"), sparing of flexures.
- Burnt soles in a child (the feet were held down in hot water).
- Small circular burns (cigarette), patterned contact burns (iron).
- Old burns with new injuries.
Pakistani context
Flame burns from gas cylinders and stoves, scalds in children and electrical burns from overhead lines are common, and many patients arrive late. Referral criteria and resuscitation practice follow local burns-centre protocols, which can change, so check current hospital or national guidance.
Expect: rule of nines values (head 9%, arm 9%, leg 18%, each side of trunk 18%, perineum 1%), the larger head (18%) and smaller legs (14%) of children, the Lund and Browder chart as the most accurate method, the patient's hand as about 1%, that erythema is not counted, how to tell superficial partial, deep partial and full-thickness burns by blisters, blanching and pinprick, healing times, and the list of burns needing transfer to a burns unit (inhalation, special areas, large burns, electrical and chemical burns, extremes of age, abuse).
Quick revision
- Adult: 9 head, 9 each arm, 18 each leg, 18 front, 18 back, 1 perineum.
- Child: head 18, each leg 14.
- Patient's hand with fingers = about 1% TBSA.
- Lund and Browder chart: most accurate, age-adjusted.
- Erythema alone is not counted.
- Superficial partial: blisters, blanches, painful, heals about 2 weeks.
- Deep partial: fixed staining, no blanching, less sensation, 3 weeks or more, scars.
- Full thickness: leathery, painless, no capillary return; needs grafting.
- Refer: inhalation, face/hands/feet/perineum/joints, large, full thickness, electrical, chemical, extremes of age, abuse.
Written by The House Job from standard surgical references (Bailey & Love; ATLS Student Course Manual).
FAQ
Why is the rule of nines not accurate in children?
A child's head is a larger share of the body surface and the legs a smaller share, so the adult values misjudge the burn. The Lund and Browder chart corrects for age.
Should simple redness be included in burn area?
No. Epidermal burns with erythema only, like sunburn, are excluded when calculating % TBSA for fluids and referral.
How can you tell a deep dermal burn from a superficial one?
A superficial partial-thickness burn is pink, moist, blistered, blanches and is very painful. A deep dermal burn has fixed red staining that does not blanch and reduced sensation.
Does a small burn of the hand need a burns unit?
Usually it should at least be discussed with one, because burns of the hands, face, feet, perineum and joints can cause serious functional problems even when small.