What causes pressure ulcers?

Damage to the skin is usually caused by one of 3 main things:
•    Pressure – the weight of the body pressing down on the skin and impeding the blood supply
•    Shear – when layers of skin are forced to slide over one another for example when you slide down or are pulled up a bed or chair
•    Friction – rubbing of the skin

The only one of these three that will cause a pressure ulcer is pressure.  The other two will cause damage to the skin but the damage will not be a pressure ulcer without pressure being present.


How do you avoid getting a pressure ulcer?

They key is to know what is normal so that you can look for changes to the skin.  Its important to regularly check your own skin or have someone else check it for you.  Check the most common places for pressure ulcers to appear such as the bottom, heels, lower back, ankles, shoulders and other bony parts of the body.  If an area of skin has changed colour (white skin to red or darker pigmented skin to blue or purple) perform a simple test, known as the blanch test, to check if there is still a healthy supply of blood to that area of the skin. 


Lightly press on the red, pink or darkened area with your finger. The area should go white; remove the pressure and the area should return to red, pink or darkened color within a few seconds, indicating good blood flow. If the area stays white or does not go white to begin with, then blood flow has been impaired and damage has begun.

Click here to watch a video of how to perform the blanch test.

Dark skin may not have visible blanching even when healthy, so it is important to look for other signs of damage like colour changes, temperature changes, swelling or hardness compared to surrounding areas.

Limit the amount of time that you sit or lie in one position.  It is recommended that people who would be considered to be more at risk should limit sitting in a chair to two hours at a time.  Use reminders to encourage you to move - the adverts on the TV, news reports on the radio or getting to the end of a chapter in a book.

If you are already or become incontinent, it is important that you keep the skin as dry and clean as possible.  Avoid scrubbing the skin when washing and pat dry with a towel.  If you have had barrier creams and sprays prescribed make sure that you know how to use them properly because incorrect application can dry out the skin.

Make sure you are eating a healthy balanced diet and taking on plenty of fluid every day.  Making sure that you body gets all the nutrients that it needs is key to maintaining healthy skin.  If your eating habits change suddenly and you become unwell make sure that you let somebody know as it could be the sign of an underlying health problem.


So the four simple things that you can check regularly:

S - Skin inspection: check for colour changes, blisters or swelling in areas which are vulnerable. 

K - Keep moving: Encourage gentle movement frequently - chair based exercise will help to encourage circulation and alleviate pressure from the key areas. Encourage movement forward and backwards, left to right in a seated position with feet flat on the floor.

I - Incontinence: is this deteriorating?  If the person at risk is incontinent then make sure a proper plan is in place and that barrier creams are being used as directed after washing and drying the skin.

N - Nutrition and hydration:is the person taking on adequate food and drink?  If not is there a problem that can be easily rectified (sore throat, mouth ulcer, broken dentures) or do they need to see a doctor?


If you want to see what pressure ulcers look like, from category I through to category IV then please click this link.  Warning, some of these are quite graphic images and can make people feel a little unwell.

If you want to use the Pressure Ulcer Triggers form that is provided for residential and domiciliary care settings, this will help you to record what you are concerned about around the five main areas for preventing risk - surface, skin inspection, mobility, incontinence and nutrition and hydration.  You can download the form here.