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What are the six stages of a pressure sore and how are they treated?

Mary Zeigler, MS

Clinical Nurse Specialist Rehabilitation Institute of Chicago

This classification system comes to us from the National Pressure Ulcer Advisory Panel, which is an extremely knowledgeable body of experts that have been writing guidelines for pressure-ulcer treatment for years.  They have come up with six stages. 

The first stage, which is the lease injury, is an injury where you have just the skin, the outer layer of skin, which is known as the epidermis, damaged.  So this will appear as pigmentation change, such as redness or pinkness on the pale-toned individual, and for the darker-toned individual, it’s going to look a little darker than their natural skin tone.  This area of pigmentation change will not blanch.  In other words, when you press your finger on it, it’s not going to change in any way; it will remain that solid color that you see.  Again, this stage only involves the outer layer of the skin known as the epidermis, and the skin is intact. 

Stage two is when you have a break in the skin; there’s further damage now.  We’ve penetrated the epidermis, we’ve broken the skin, and we’re now involved with the dermal layer, the next layer.  The dermis looks red, now it is considered a partial-thickness injury; this is a stage two.  The treatment for a stage one and a stage two is, of course, relief of pressure until there’s complete resolution of the color change, and until the skin become intact again.  We have a variety of treatments, we have creams that reduce friction and shear, we have special transfer sheets and the like, that we treat this level of damage to the skin. 

The next stage is a stage three.  Now we have a full-thickness injury.  We have penetrated through the dermal layer, beyond the epidermis, into what we call the subcutaneous layer.  The wound itself will look red, and it may have necrotic tissue in it.  Necrotic tissue is dead tissue, we don’t want dead tissue.  We want to get rid of all the dead tissue to make room for healthy tissue to grow.  Dead tissue can be a variety of colors—yellowish, blackish, grayish, even whitish—this is the stage three pressure ulcer.  There has to be relief of pressure until this wound resolves, and we use, again, a wide range of different treatments depending on the character of the wound.  If the wound is a highly draining wound, we’re going to use an absorbent dressing, a dressing that wicks away the drainage.  If it’s a very dry wound, we need to give the wound moisture, and so forth. 

A stage four pressure ulcer is a full-thickness injury, where the damage has extended into the muscle, and perhaps into the bone, the tendon or joint capsule.  You may see bone, you may palpate bone, you may see tendon, you may see muscle.  This is a large cavity wound, usually of depth, and of course, you must have relief of pressure until there’s resolution, and similar modalities of treatment are used as with stage three pressure ulcer. 

The next stage is what we refer to as “unstageable,” but it is a stage.  An unstageable pressure ulcer is when it is completely covered with necrotic or dead tissue, so that you cannot visualize the wound base.  So we don’t know what the extent of damage is until we’ve removed, or what we call, “debride,” the necrotic tissue.  Then we can classify this wound as either a stage three or stage four. 

The last stage is what we call the “suspected deep-tissue-injury.”  This wound will appear intact, but it will be bruised looking, and it will have a tissue texture consistency that is soft instead of firm.  And what’s happening here with the suspected deep tissue injury is that there is injury at the bony tissue interface; that’s where the bone meets the tissue.  So there’s tissue damage going on underneath, and it has not reached the surface of the skin, or the epidermis.  So the skin remain intact, but in many instances, the suspected deep-tissue-injury subsequently  heralds a stage three or stage four full-thickness pressure ulcer.