A pressure sore is also known as a 'bed sore' or a 'pressure ulcer'. It is a sore or broken (ulcerated) area of skin caused by irritation and continuous pressure on part of your body.
Pressure sores are more common over places where your bones are close to your skin (bony prominences) such as your heels, the lower part of your back and your bottom. There are various things that can increase your risk of developing a pressure sore. In particular, risk increases if your mobility is reduced for some reason and you are spending long periods lying in bed or sitting in a chair.
There are various measures you can take to prevent most pressure sores developing. These include changing your position as much as possible and also using pressure-relieving devices.
What is a pressure sore?
A pressure sore is an ulcerated area of skin caused by irritation and continuous pressure on part of your body. It starts as an area of skin damage. The damage can then spread to your tissues underlying your skin. In very severe cases, there can be permanent damage to muscle or bone underneath your skin. This is not common though. Pressure sores can be very painful and can take a very long time to heal.
Pressure sores can affect any area of your body but are more common over places where your bones are close to your skin (bony prominences). Common areas for pressure sores to occur are around the lower part of the backbone and buttocks (your sacrum), your heels, your elbows, your hips, your back, your bottom, the back of your head and your shoulders.
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Pressure sores can develop very quickly. In people who are at high risk (see below), it can take less than an hour for a pressure sore to develop.
What causes pressure sores?
Pressure sores are caused by the pressure from the weight of your body pressing down on your skin. They usually occur when a place where you have bone close to your skin (a bony prominence) is pressed against a surface such as a chair or a bed. This compresses your skin and your underlying tissues and can also damage blood vessels. Rubbing (friction) of your skin can also play a part in the formation of a pressure sore.
If you are spending long periods in bed or in a chair, you may slide down and need to be pulled back up again by someone else (or you may be able to pull yourself back up). However, as these sliding and pulling movements happen, the layers of your skin also slide over each other, as well as over the underlying tissues. These sliding, or 'shearing', forces can also contribute to pressure sore formation. Changes to your skin as it ages may make this sliding of your skin more likely.
A lot of moisture around your skin (for example, if you have urinary or stool (faecal) incontinence or you are sweating a lot) can increase the effects of pressure, friction and shearing forces. Damp skin becomes softer and more fragile.
Using the correct preventative measures (see below) should mean that most pressure sores are avoidable.
Who develops pressure sores?
Most pressure sores occur when someone is admitted to hospital. They affect between 1 to 5 in every 100 people admitted to hospital. However, pressure sores can also develop in someone at home, or in a nursing or residential home.
A pressure sore is more likely to develop if you:
- Are seriously ill (including someone in an intensive care unit).
- Are not very mobile (for example, you may be confined to a chair or a bed), particularly if you are not able to change your position without help from someone else.
- Have had a spinal cord injury (this means you are unable to move or feel your legs and sometimes your arms).
- Have a poor diet.
- Are wearing a prosthesis (for example, an artificial limb), a body brace or a plaster cast.
- Are a smoker.
- Are incontinent of urine or stool (faeces). This causes damp skin which is more easily damaged.
- Have diabetes (this can affect sensation and ability to feel pain over parts of your body).
- Have chronic obstructive pulmonary disease (COPD) or heart failure.
- Have Alzheimer's disease, Parkinson's disease or rheumatoid arthritis.
- Have recently had a broken hip or undergone hip surgery.
- Have poor circulation in your legs or arms, caused by narrowing of your arteries by atheroma (peripheral arterial disease).
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Pressure sore staging
Pressure sores can look different depending on how severe they are. They are graded depending on their severity and how deep they go:
- Grade 1 - your skin is permanently red but is not broken at all. It may feel warm, hard or slightly swollen. In dark-skinned people, your skin may be purple or blue in colour.
- Grade 2 - the skin is broken (an ulcer) but the ulcer is still superficial. It may look like a blister or abrasion.
- Grade 3 - the ulcer goes through the full thickness of the skin and there is damage to the tissues underneath the skin.
- Grade 4 - this is the most severe form. The ulcer is deep and there is damage to muscle or bone underneath.
Pressure sore prevention
The National Institute for Health and Care Excellence (NICE) has produced guidelines with recommendations for best practice for the prevention of pressure sores (ulcers). NICE recommends that all people who are admitted to hospital, a nursing home or similar, or people who are receiving nursing care at home, should be assessed for their risk of developing a pressure sore. This is usually done by a healthcare professional (usually a nurse). This assessment should be reviewed regularly because your situation may change.
There are various pressure sore risk assessment scales that may be used, looking at factors such as your diet, your mobility, your continence, your consciousness level and any underlying illnesses that you may have, etc.
If you are assessed and found to be at increased risk then one or more of the following may be suggested:
1. Change your position as much as possible
Ideally, you should get up and move around as much as possible. However, if this is not feasible, you should change your position as much as possible when you are sitting or lying in bed. You may need help from someone else to change your position. Changing your position means that you are relieving pressure on areas of your body that may be prone to developing pressure sores. Ask your healthcare professional for advice about:
- How to sit or lie.
- How often you should move or have help with your position change and what position you should move to.
- How to support your feet.
- How to maintain a good posture (for example, how to stop your body slipping down in a chair).
2. Make sure you eat and drink the right things
It is important that you are eating a balanced diet and drinking plenty of fluids to help prevent pressure sores. Your healthcare professional may discuss your diet with you to see if it is likely that you are lacking in any nutrients. They may refer you to a dietician and/or you may be advised to take some supplements.
3. Use pressure-relieving devices
There are various devices that are available that can help to relieve pressure and prevent pressure sores. They include special beds, mattresses, cushions and overlays (these are placed on top of a mattress). They can work in the following ways:
- Spreading out the pressure (for example, by moulding around the body).
- Regularly removing pressure from different parts of the body (these are the more 'high-tech' devices).
All the surfaces that you sit or lie on need to be considered for pressure-relieving devices. This includes chairs and beds.
Mattress pads (overlays) lie on top of the mattress to help decrease pressure on the skin. This helps to prevent sores in people who have to stay in bed most of the time. There are many different types of mattress pads, such as egg crate mattress pads and alternating pressure pads.
4. Make regular checks of your skin
Your healthcare professional should check your skin regularly to look for any signs of a pressure sore. You or your carer may also be able to check your skin (this may sometimes need the help of a mirror). Tell your healthcare professional if there are any areas of your skin that you are worried about.
Pressure sore treatment
If you already have a pressure sore, it should be assessed by a qualified healthcare professional. They may want to take a tracing or a photograph of the sore. This can then be used to monitor your response to treatment. They should be able to determine what grade of pressure sore you have, look for any signs of infection and try to work out what caused the sore.
For a pressure sore to heal, you need to change your position as much as possible (as described above) and also to use pressure-relieving mattresses and cushions. These both help to relieve the pressure on the pressure sore.
Seating is very important for pressure sores on the buttocks. The use of pressure cushions alone will not help the pressure sore to heal if posture is not properly assessed and the cause of the pressure sore identified. Chairs that are the wrong size or not adaptable to posture and positioning will increase the risk of developing pressure damage.
Current recommendations are that someone with a pressure sore should use a high-specification foam mattress. A high-specification foam or equivalent pressure-redistributing cushion should be used if you use a wheelchair or sit for prolonged periods.
Other treatments are often needed for pressure sores. These may include:
- Pain relief - a pressure sore can be painful. Simple painkillers like paracetamol may be helpful. Sometimes stronger painkillers are needed.
- A change to your diet - a poor diet can slow the healing of a pressure sore.
- Dressings - various different dressings may be used, including gel and foam-based dressings.
- Antibiotics - these may be needed if there are any signs of infection.
- Surgery - sometimes surgery is needed to remove damaged or dead skin. The medical term that is used for this type of surgery is 'debridement'. Sometimes plastic surgery may be used to close a pressure sore that is not healing. Skin grafts may be needed.
Are there any complications of pressure sores?
If treatment is started early, pressure sores usually cause few if any complications. Complications are much more likely with advanced stages of pressure sores.
A pressure sore can become infected. Rarely, this infection can spread to the surrounding skin (cellulitis), to your blood (causing 'blood poisoning', or sepsis), or it can spread to your bone underneath the pressure sore (causing osteomyelitis). In severe cases, a pressure sore can cause permanent damage or loss of muscle or bone underneath the affected area of skin.
Other possible complications that may occur with advanced stages of a pressure sore include anaemia, kidney failure, coma and even death.
What is the outlook for pressure sores?
The outlook (prognosis) for pressure sores is usually good if they are treated before they reach an advanced stage and before any complications develop.
The outcome can be much worse for advanced stages of pressure sores that aren't treated early enough. The outcome will also depend on where the pressure sore is on your body, your general well-being and how well you respond to the treatments.
If you have a pressure sore, you're more likely to develop another pressure sore in the future.
Further reading and references
Pressure ulcers: prevention and management of pressure ulcers; NICE Clinical Guideline (April 2014)
Treatment of Pressure Ulcers: Quick Reference Guide; National Pressure Ulcer Advisory Panel, 2014
Boyko TV, Longaker MT, Yang GP; Review of the Current Management of Pressure Ulcers. Adv Wound Care (New Rochelle). 2018 Feb 17(2):57-67. doi: 10.1089/wound.2016.0697.