Burn injury results from exposure to heat, chemical, or electricity. The extent of the injury is dependent upon temperature and duration of exposure, as well as the vascular supply and the thickness of the injured skin. At the center of the exposure there is an irreversible tissue necrosis. Surrounding the area of central necrosis is a zone of ischemia in which there is a reduction in dermal microcirculation. This ischemic zone may progress to full necrosis unless the ischemia is reversed. At the periphery of the burn is a third zone of hyperemia characterized by a reversible increase in blood flow.
In the United States in 2012, there were approximately 450,000 emergency department/urgent care/outpatient visits resulting in 40,000 acute hospitalizations for burn injuries. There were 2,550 deaths from residential fires and an additional 550 deaths from other sources including motor vehicle crashes, aircraft crashes, and contact with electricity, chemicals or hot liquids. The World Health Organization (WHO) states a high percentage of patients admitted to burn units worldwide are children younger than 12 years. Fortunately, most burns are superficial and involve less than 5% of total body surface area (TBSA).
Superficial burns in children result most from scalding with hot liquids. Deeper burns are usually secondary to direct contact with flame, hot objects, chemicals, and electricity. Smoke inhalation is seen in 18% of reported injuries and has a significant impact on mortality and length of hospital stay.
Burns are classified by depth and surface area of skin involved:
First-degree burns involve the epidermal layer only. This results in pain and erythema but the burn usually heals in a few days without scarring.
Second-degree burns involve the epidermis and part of the underlying dermis. They are further classified based on the depth of injury:
Superficial partial-thickness burns are characterized by erythema, blister formation, and weeping. They are painful but generally heal in 1-2 weeks with minimal to no scarring.
Deep partial-thickness burns involve the reticular and the papillary layers of the dermis and the burn does not blanch with pressure. A nonelastic red or white layer on top of the burn characterizes these burns. They require up to 3-4 weeks to heal and will often have significant scarring.
Third-degree (full-thickness) burns are characterized by an injury with a thick white, brown, or tan overlying layer with a leathery texture. They are insensate and do not blanch. The surrounding area may have painful, deep partial-thickness burn. These burns require excision and skin grafting.
Fourth-degree burns are characterized by involvement of all layers of ...