The skin helps maintain the delicate FLUID AND ELECTROLYTE BALANCE essential for life. After a burn injury, massive FLUID loss occurs through excessive evaporation. The rate of evaporation is in proportion to the total body surface area (TBSA) burned and the depth of injury.
The skin is an excretory organ through sweating. Full-thickness burns destroy the sweat glands, reducing excretory ability.The sensations of PAIN, pressure, temperature, and touch are triggered on the skin in normal daily activities, which allows a person to react to changes in the environment. All burn injuries are painful. With partial-thickness burns, nerve endings are exposed, increasing sensitivity and PAIN. With full-thickness burns, nerve endings are completely destroyed. At first, these wounds may not transmit sensation except at wound edges. Despite this destruction, patients often have dull or pressure-type of pain in these areas.Skin exposed to sunlight activates vitamin D. Partial-thickness burns reduce the activation of vitamin D, and this function is lost completely in areas of full-thickness burns.The internal body temperature remains within a narrow range (about 84.2° to 109.4° F [29° to 43° C]) compared with the temperatures of the external environment. Skin TISSUE INTEGRITY is important in maintaining normal body temperature. Circulating blood in the skin both provides and dissipates heat efficiently. When heat is applied to the skin, the temperature under the dermis rises rapidly. As soon as the heat source is removed, compensatory processes quickly return the area to a normal temperature. If the heat source is not removed or if it is applied at a rate that exceeds the skin's capacity to dissipate it, cells are destroyed.Physical identity is partly determined by the skin's cosmetic quality, which contributes to each person's unique appearance. A patient who sustains a major burn often develops reduced self-image and other psychosocial problems as a result of a change in appearance.Depth of Burn InjuryThe severity of a burn is determined by how much of the body surface area is involved and the depth of the burn. The degree of TISSUE INTEGRITY loss is related to the agent causing the burn and to the temperature of the heat source, as well as to how long the skin is exposed to it.Differences in skin thickness in various parts of the body also affect burn depth. In areas where the skin is thin (e.g., eyelids, ears, nose, genitalia, tops of the hands and feet, fingers, and toes), a short exposure to high temperatures causes a deep burn injury. The skin is thinner in older adults (Touhy & Jett, 2014), which increases their risk for greater burn severity, even at lower temperatures of shorter duration.Burn wounds are classified as superficial-thickness wounds, partial-thickness wounds, full-thickness wounds, and deep full-thickness wounds. The partial-thickness wounds are further divided into superficial and deep subgroups.