Burns are incurred from thermal sources (as in the case of sunburn, direct heat, or scalding), electrical damage, or chemical exposure. The management and prognosis of burns depend on their severity. Burns, traditionally classified as first, second, or third degree, are now classified using terminology that more accurately reflects the tissue involvement: superficial, partial thickness, deep dermal partial thickness, and full thickness. Other factors that influence outcomes and management of burns include extent (% total body surface area) of the injury, site of injury, type of inciting agent and duration of exposure, and whether or not infection occurs.

Scalding hot and flammable liquids and fires are responsible for the most serious burns; chemical-, electrical-, and smoking-related incidents can also cause severe injury. By losing the protective barrier of the skin, burns predispose their victims to infections, the major cause of morbidity and mortality in this population. Infections that complicate burns result in up to 10,000 deaths per year in the United States alone. Compounding the problem of infection, those with significant burns suffer systemic immunosuppression from an impaired population of white blood cells, including reduced helper T cells and increased suppressor T cells.

Extent.