Critical Care Trauma Centre


Thermal Burns                                                               

How are Burns Classified?
Partial Thickness 
(1st degree)

  • superficial burns are limited in depth to the first 2 or 3 of the 5 layers of the epidermis 
  • characterized by erythema, hyperemia, tenderness and pain
  • no vesicles or blisters
  • due to the shallow depth, regeneration of skin will occur within several days
Moderate Partial Thickness 
(2nd degree)

  • burns involve entire epidermis (blue zone) and upper third of dermis (mauve zone)
  • skin will usually appear red
  • injury to microvessels that perfuse the skin results in wet wounds with bullae and blisters
  • very painful; pain increases when exposed to air currents
  • will heal within 1 - 6 weeks with minimal scarring

Deep Partial Thickness 
(2nd degree)

  • burn includes the entire epidermis and deep into the dermis
  • impairment of blood supply often limits fluid leakage; blisters are not usually present and only a modest amount of plasma leakage appears on the wound
  • wound usually red with white appearance in center; blanches following assessment for capillary refill
  • dermal necrosis and surface protein turns gives burn surface a yellow appearance
  • will heal spontaneously by slow granulation, often leaving unstable epithelium, scarring and contractures
  • grafting is the desired treatment as it improves the quality of the healing (better cosmetic and functional healing) and reduces the opportunity for infection
  • can progress to full thickness injuries if infection develops

Full Thickness Burn
(3rd degree)

  • results in destruction of skin through all layers of epidermis and dermis, extending into subcutaneous fat and underlying tissue
  • subcutaneous layer contains hair follicles and sweat glands and is poorly vascularized; this is below the stratum germinativum layer (dark blue area) which is responsible for the generation of new skin cells
  • burn appears white, red or brown and is often charred and leathery in appearance 
  • skin is usually dry and insensitive to pin or palpation
  • if skin is broken, subcutaneous fat may be visible
  • associated with extensive fluid and electrolyte imbalances, altered thermoregulation, metabolic disturbances and infection
  • although small wounds will contract and eventually heal, larger wounds require grafting 

Diagram 1

blue area

Stratum Germinativum: 
dark blue area

mauve area

Subcutaneous Fat: 
yellow area

Burn Depths:
partial thickness (1)
moderate partial thickness (2)
deep partial thickness (3)
full thickness (4)

Diagram 1

Calculation of Percentage of Burned Area

Management and Monitoring of the Burned Patient

Derek Brzozowski and Brenda Morgan.  (October 23, 2000)

Thelan, L., Urden, L., Lough, M., & Stacy, K. Critical Care Nursing: Diagnosis and Management. Mosby: Toronto.  pp. 1141-1170.