Stages of Pressure Injuries

Art & Research: Xiaoying Wu

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What Are Pressure Injuries?

Ever heard of bed sores? Or pressure ulcers? They are also known as pressure injuries! Pressure injuries are the breakdown of skin areas that are under pressure for a long period of time (NCBI - Pressure Ulcer). So how do they happen? Pressure injuries occur when there is a reduced blood flow to an area of the skin due to pressure, and the lack of blood flow leads to the death of skin cells (CDC). Common sites of pressure ulcers include the heels, buttocks, lower back, elbows, and the back of the head (Mayo Clinic). This is a serious medical condition, and treatment is advised as soon as possible.

Stage 1 Pressure Injury

Pressure injuries can occur as early as 2 hours of having the skin under pressure. In stage 1, the skin will be red or pink, and it is nonblanchable, meaning that the redness of the skin does not go away when pressing on it. There is no skin breakdown yet, and thus the skin is still intact. (NCBI - Pressure Ulcer)

Stage 2 Pressure Injury

In stage 2 of a pressure injury, there is partial thickness loss of skin where the epidermis, or the outermost layer of skin, is broken down. Part of the dermis, or the middle layer of skin, is broken down as well. (NCBI - Pressure Ulcer)

Stage 3 Pressure Injury

In stage 3 of a pressure injury, the skin is fully broken down to where the subcutaneous layer is visible. The subcutaneous layer is also known as the fatty tissue layer. Thus, yellow fatty tissue will be visible at stage 3. (NCBI - Pressure Ulcer)

Stage 4 Pressure Injury

At stage 4 of a pressure injury, there is total loss of skin and fatty tissue, where the muscles and bone are exposed. (NCBI - Pressure Ulcer)

Deep Tissue Injury & Unstageable

Some pressure injuries are unstageable because they can be covered by dry, black, dead tissue called eschar or yellow dead tissue called slough (NCBI - Wound Assessment). It may be required to remove the dead issue to view the base of the injury in order to determine the stage. On the other hand, a deep tissue injury is when the underlying tissue is damaged, leading to a purple or maroon color of the intact skin (NCBI - Differential diagnosis of suspected deep tissue injury).


Patients on bed rest are at risk of developing pressure injuries due to the lack of movement. Thus, it is important for people, especially those with medical conditions, to change their positions at least every 2 hours to relieve the pressure and prevent pressure injuries (NCBI - Preventing pressure ulcers)!

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