Pressure sores (bed sores) are an injury to the skin and underlying
tissue. They can range from mild reddening of the skin to severe tissue
damage—and sometimes infection—that extends into muscle and bone. Pressure
sores are described in four stages:
Stage 1 sores are not open wounds. The
skin may be painful, but it has no breaks or tears. The skin appears
reddened and does not blanch (lose color briefly when you press your finger on it then remove your finger). In a dark-skinned person, the area may appear to be a different color than the surrounding skin, but it may not look red. Skin temperature is often warmer. And the stage 1
sore can feel either firmer or softer than the area around it.
stage 2, the skin breaks open, wears away, or forms an
ulcer, which is usually tender and painful. The sore expands into deeper layers
of the skin. It can look like a scrape (abrasion), blister, or a shallow crater
in the skin. Sometimes this stage looks like a blister filled with clear fluid.
At this stage, some skin may be damaged beyond repair or may die.
During stage 3, the sore gets worse and extends into the
tissue beneath the skin, forming a small crater. Fat may show in the sore, but
not muscle, tendon, or bone.
At stage 4, the
pressure sore is very deep, reaching into muscle and bone and causing extensive
damage. Damage to deeper tissues, tendons, and joints may occur.
In stages 3 and 4 there may be little or no pain due to
significant tissue damage. Serious complications, such as infection of the bone
(osteomyelitis) or blood (sepsis), can occur if pressure sores progress.
Sometimes a pressure sore does not fit into one of these stages.
In some cases, a deep pressure sore is suspected, but cannot be
confirmed. When there isn't an open wound but the tissues beneath the surface
have been damaged, the sore is called a deep tissue injury (DTI). The area of
skin may look purple or dark red, or have a blood-filled blister. If you or
your doctor suspect a pressure sore, the area is treated as though a pressure
sore has formed.
There are also pressure sores that are
"unstageable," meaning that the stage is not clear. In these cases, the base of
the sore is covered by a thick layer of other tissue and pus that may be
yellow, gray, green, brown, or black. The doctor cannot see the base of the
sore to determine the stage.
Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
Margaret Doucette, DO - Physical Medicine and Rehabilitation, Wound Care, Hyperbaric Medicine
E. Gregory Thompson, MD - Internal Medicine & Margaret Doucette, DO - Physical Medicine and Rehabilitation, Wound Care, Hyperbaric Medicine
How this information was developed to help you make better health decisions.