The white arrow points an area of recent burn, where the skin has been denuded by the recent burn. The black arrow points to an area where the burn has already healed with the formation of a large area of hypo-pigmented scar tissue. Burns can occur due to a variety of reasons, including exposure to fire or fluids at high temperature, chemicals such as acids, bases and oxidizing agents, high voltage electricity and exposure to the sun.
Burns cause coagulation necrosis of exposed tissues.
Burns are classified as partial or full thickness depending upon the depth to which the skin has been subjected to injury. In partial thickness wounds, only the superficial layers of the epidermis are subjected to injury. Cells show evidence of coagulation necrosis and are converted into a uniform pink staining material. In full thickness burns, the entire epidermis, parts or all of the dermis, and the subcutaneous tissue may be injured. As with a particular thickness burn, the tissue involved is converted into a homogenously staining material.