Forensic pathology
Types of injuries
Fire Deaths

Author: Lindsey Harle, M.D. (see Authors page)

Revised: 12 January 2017, last major update July 2012

Copyright: (c) 2012-2017, PathologyOutlines.com, Inc.

PubMed search: forensics fire death

Table of Contents
Definition / General
Cite this page: Fire Deaths. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/forensicsfiredeaths.html. Accessed February 22nd, 2017.
Definition / General
Classification of burns:
  • 1st degree: limited to superficial epithelium; erythematous with pain, edema, skin peeling; does not scar
  • 2nd degree: involves full thickness epidermis and superficial dermis; skin appendages are spared; blistering, painful; usually do not scar
  • 3rd degree: involves all skin layers, including full thickness dermis and skin appendages; no pain due to nerve injury; appears white; severe scarring
  • 4th degree: complete destruction of skin, subcutaneous tissue and possibly bone
Documenting thermal injury:
  • Extent of injury recorded as percentage of body surface area; use rule of 9s in adults, chart #2
  • Age adjusted body surface area chart for children; use rule of 5s for infants and young children
Factors affecting burns:
  • Heat intensity, duration of exposure, presence / absence of clothing
Types of burns
  • Flame: occurs when skin is in direct contact with flame
    • Flash burn is due to sudden explosion of gas or particulate matter; produces uniform burn over all exposed skin
  • Contact: occurs when skin is in direct contact with a hot object (e.g. iron)
    • May show pattern injury reflective of the hot object
  • Radiant: occurs when skin is exposed to heat waves; produces blistering and erythema
  • Scalding: occurs when skin contacts hot liquid
    • Immersion burn: occurs commonly when child is placed in tub of hot water
    • May indicate child abuse; as child flexes to avoid water, areas of skin are spared around knees and inguinal region
    • Splash or spill burn: cased by splashing of hot liquid; usually accidental in nature
    • Burn pattern should correspond to the scene description, with more severe burns near the initial point of contact (e.g. child’s hand or head when a pot of liquid is pulled off the stove)
    • Steam burn: can cause severe laryngeal edema when inhaled
  • Microwave: occurs when skin is exposed to electromagnetic waves; usually accidental
    • Tissue with higher water content shows more severe injury (e.g. muscle burns more rapidly than fat)
  • Chemical: occurs when strong acids or alkali contact skin; can also be caused by phosphorus or phenol
    • Burns develop more slowly than those created by thermal injury
    • Alkali agents tend to cause more severe injury; are usually full thickness and appear pale and leathery
    • Acid burns usually are partial thickness and appear erythematous and erosive
Mechanism of death
  • Immediate mechanism of death due to thermal injury
    • Neurogenic shock secondary to severe pain
    • Hypovolemic shock and acute renal failure due to loss of fluid from skin
    • Toxic gas inhalation - CO (most common), cyanide, acrolein, nitrogen dioxide, hydrochloric acid
      • Often see soot in nose / mouth
      • May produce edema, mucosal necrosis of upper airway, or bronchospasm
      • CO levels usually 30% - 60% in fire deaths
  • Delayed mechanism of death due to thermal injury
    • Delayed hypovolemic shock with renal failure
    • ARDS
    • Infection (pneumonia, sepsis, cutaneous)
    • Pulmonary embolus due to immobilization
Postmortem changes in charred / burned bodies
  • Pugilistic attitude: flexion of the upper extremities as the body cools
  • Does not reflect ante- or perimortem body position
  • Skin / muscle splits: occur parallel to muscle fibers; can extend into body cavities
  • Should not be confused with antemortem trauma
  • Loss of fingers / toes / extremities: due to charring or loss at the scene
  • Heat epidural: blood boiling out venous sinuses produces postmortem epidural blood pooling
  • Weight and length measurements are unreliable
Classification of fire deaths
  • Death due to an intentionally set fire is generally a homicide
  • Suicidal if the individual sets him / herself on fire
  • Look for accelerants or volatiles on clothing from the decedent
  • Many fires are accidental
  • Antemortem versus postmortem burn
    • Postmortem burns may appear yellow and dry; microscopic evaluation should reveal no inflammatory reaction
    • Some postmortem burns can be impossible to distinguish from antemortem burns