What a pressure injury stage tells you

Here are the pressure injury stages explained in everyday language. A pressure injury (also called a bed sore or pressure ulcer) is damage to the skin and the tissue under it caused by pressure, often combined with sliding or rubbing. It usually forms over a bony area such as the tailbone, hips, heels, ankles or elbows.

The stage is a label for how deep the damage goes at the time of the exam. It does not predict how long healing will take.

The four numbered stages

Stage 1: unbroken skin that stays discolored

The skin is intact. On light skin there is a red area that does not turn pale when it is pressed and released. The spot may feel warmer, cooler, firmer or softer than the skin around it.

Stage 2: a shallow open area or blister

The top layers of skin are damaged. You may see a shallow, moist, pink or red open area, or a blister filled with clear fluid. No fat or deeper tissue is visible.

Stage 3: through the full thickness of the skin

The wound goes through the skin into the fatty layer beneath and often looks like a crater. There may be yellow dead tissue in it, and the edges may have a pocket underneath. Muscle, tendon and bone are not visible.

Stage 4: down to muscle, tendon or bone

Muscle, tendon or bone is exposed or can be felt in the wound, and tunnels are common. Because bone is close, the clinician watches for deep infection and may order imaging or lab tests.

Two categories without a number

  • Unstageable. The base of the wound is hidden under yellow, tan, brown or black dead tissue, so the true depth cannot be seen. Once the base is visible, the wound is given a stage.
  • Deep tissue pressure injury. A lasting deep red, maroon or purple area, or a blood-filled blister, on skin that may still be intact. The damage began in deeper tissue near the bone. It may open into a deeper wound, or it may resolve.

What a stage does not tell you

  • Stages do not run backward. A stage 4 that is filling in is called a healing stage 4, not a stage 2. The body fills the space with scar tissue, not with the original layers of muscle and fat.
  • Injuries do not always climb the stages in order. Deep damage can appear suddenly as a dark area or an unstageable wound.
  • A stage is not the whole picture. Size, drainage, pain and infection are recorded separately. The guide to understanding wound measurements explains those numbers.
  • Not every sore on the bottom is a pressure injury. Skin damaged by urine, stool or sweat is managed differently. See the page on moisture-associated skin damage.

Questions to ask when you hear a stage

  1. What stage is it, where is it and when was it first noticed?
  2. What is being done to keep pressure off that spot?
  3. How often will it be measured, and who will give me updates?
  4. What should I watch for between visits?

The guides to a repositioning schedule at home and to cushions and mattresses for pressure relief explain the pressure relief options a clinician may bring up.

What to report

Tell the treating clinician or the facility nurse about:

  • A red, purple or dark area that has not faded after the person has been moved off it
  • A new blister or open area, or dark tissue appearing in a wound
  • A wound that is getting larger or deeper
  • A new odor, thick drainage, spreading redness or warmth
  • More pain, or grimacing and guarding in someone who cannot describe pain
  • Fever, chills, new confusion or unusual sleepiness

Call 911 for trouble breathing, a sudden change in alertness, or shaking chills with a high fever.

How Gateway helps with pressure injuries

Gateway arranges visits with partner clinicians in homes and facilities across Greater St. Louis and the Metro East. The treating clinician examines and stages the wound and writes the plan. We coordinate scheduling, records, supply orders and updates to the family members the patient wants included.

Read more about pressure injury and bed sore care, pressure injury prevention and skin checks in primary care. Family caregivers can start with the pressure injury caregiver guide. To ask about a visit, call 314-325-0126 or send a request for care.

Common questions

Is a bed sore the same thing as a pressure injury?

Yes. Bed sore, pressure sore, pressure ulcer, decubitus ulcer and pressure injury all refer to the same problem. “Pressure injury” is the current term because the earliest stage and deep tissue injuries can occur under skin that is still closed, so “ulcer” did not fit every case.

Why did the stage change after the wound was cleaned up?

An unstageable wound is hidden under dead tissue, so its depth is hidden. After a clinician removes that tissue, the base is visible and the wound gets a number, usually a 3 or a 4. That change does not mean the wound suddenly became worse. It means the true depth can finally be seen.

Can a stage 1 pressure injury go away?

Often it can, if the pressure is taken off the area early and kept off. That is why a red or dark spot that does not fade deserves a report right away. Ask the nurse or clinician what should change, such as position, surface or footwear. Do not rub the area.

How do I check for early pressure damage on dark skin?

Redness can be hard to see on dark skin, so compare the area with the skin around it and with the same spot on the other side of the body. Look for a patch that appears darker, purplish or ashen. Then feel it. Skin that is warmer or cooler, firmer or softer, swollen or tender is worth reporting.

Related pages

General information to help you talk with your own clinician. It is not medical advice, and the treating clinician makes every clinical decision. For a medical emergency, call 911.

Updated October 2026