ENCYCLOPEDIA
BRITANNICA:
Physicians have traditionally categorized burns as first-,
second-, or third-degree injuries, according to the depth of skin damage. In a
first-degree burn, only the epidermis is affected. These injuries are
characterized by redness and pain; there are no blisters, and edema (swelling
due to the accumulation of fluids) in the wounded tissue is minimal. A classic
example of a first-degree burn is moderate sunburn.
The damage in a second-degree burn extends through the
entire epidermis and part of the dermis. These injuries are characterized by
redness and blisters. The deeper the burn the more prevalent the blisters,
which increase in size during the hours immediately following the injury. Like
first-degree burns, second-degree injuries may be extremely painful. The
development of complications and the course of healing in a second-degree burn
depend on the extent of damage to the dermis.
Third-degree, or full-thickness, burns destroy the entire
thickness of the skin. The surface of the wound is leathery and may be brown,
tan, black, white, or red. There is no pain, because the pain receptors have
been obliterated along with the rest of the dermis. Blood vessels, sweat
glands, sebaceous glands, and hair follicles are all destroyed in skin that
suffers a full-thickness burn. Fluid losses and metabolic disturbances
associated with these injuries are grave.
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