Below are images of pressure ulcers from category I through to unstageable deep tissue damage.

Category I: Non-blanching erythema

Intact skin with non-blanchable redness of a localised area usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its colour may differ from the surrounding area.

Category II: Partial thickness skin loss

Partial thickness loss of dermis presenting as a shallow open ulcer with a red pink wound bed. May also present as an intact or open/ruptured serum-filled blister.

Category III: Full thickness skin loss

Full thickness tissue loss. Subcutaneous fat may be visible but bone, tendon or muscle are not exposed.

Category IV: Full thickness skin loss

Full thickness tissue loss with exposed bone, tendon or muscle.

Unstageable: depth unknown

Full thickness tissue loss in which the base of the ulcer is covered by slough (yellow, tan, gray, green or brown) and/or eschar (tan, brown or black) in the wound bed.

Suspected Deep Tissue Injury: depth unknown

Purple or maroon localised area of discoloured intact skin or blood-filled blister due to damage of underlying soft tissue from pressure ulcer and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, warmer or cooler as compared to adjacent tissue.