Bedsores, also called pressure sores or pressure ulcers, are one of the harder parts of caring for someone who cannot move around easily. They can appear quickly and heal slowly, which is worrying when you are the one looking after the person.
The good news is that once you understand what causes them, a lot of the care becomes clear.
This guide explains what causes bedsores, where they form, how to help one heal, and the signs that mean it is time to call for medical help.
What causes a bedsore?
A bedsore is caused by constant pressure on one area of skin, which squeezes the small blood vessels shut and cuts off the blood supply. Without blood, the skin and the tissue beneath it are starved of oxygen, and they start to break down.
This happens fastest where a bone sits close to the surface, because the skin there gets pinched between the bone and the bed or chair.
Two other things make it worse. Friction, when skin rubs against a surface, and shear, when the skin is dragged one way while the body slides another, both damage the skin. Moisture from sweat or leaks softens the skin and makes it break down more easily. Put these together with unrelieved pressure and a sore can form in hours.
Who is most at risk of bedsores?
The people most at risk are those who cannot move or shift their weight on their own. If a person stays in one position for long periods, the same patch of skin takes the pressure without relief.
That includes people confined to bed, people who use a wheelchair, and anyone recovering from a serious illness or surgery.
A few things raise the risk further. Reduced feeling in the skin, from paralysis or nerve damage, means the person does not feel the discomfort that would normally make them move. Poor nutrition and weight loss leave the skin thin and fragile. And moisture from incontinence or heavy sweating weakens the skin. The more of these that apply, the closer the watch needs to be.
Where do bedsores usually form?
Bedsores form over the bony points that take the most pressure, and these change depending on how the person is lying or sitting. Knowing the map helps you check the right places.
For someone lying on their back, the common spots are the tailbone, the heels, the shoulder blades, and the back of the head.
For someone lying on their side, it is the hips, the outer knees and ankles, and the ears. For someone sitting for long periods, the tailbone and the buttocks take the load. Check these areas every day, since a sore caught at the first sign is far easier to deal with.
What do the early signs of a bedsore look like?
The earliest sign is a change in the skin over a pressure point, usually before the skin is broken. On lighter skin this often looks like a red patch that does not turn pale when you press it gently.
On brown and darker skin, redness can be hard to see. The area may instead look purple, blue, or darker than the skin around it, and it may feel warmer, cooler, firmer, softer, or more painful than nearby skin.
Trust changes you can feel as much as ones you can see.
If you notice any of these, treat it as an early warning. Take the pressure off that area straight away and keep a close eye on it, because acting at this stage can stop a sore from opening up at all.
How can you help a bedsore heal?
The single most important step is to take the pressure off the sore, because it cannot heal while it is still being crushed. Reposition the person regularly, usually about every two hours in bed and more often in a chair, following any schedule the nurse has set.
A pressure-relieving mattress or cushion spreads the load and takes pressure off the vulnerable spots between turns.
Keep the skin clean and dry, and manage any moisture from leaks or sweat quickly. The wound itself needs proper care from a nurse or doctor, so follow their dressing advice rather than improvising.
Good nutrition supports all of this by giving the body the protein and nutrients it needs to rebuild skin. Our guide on what to feed someone with a bedsore covers that side in detail. Food and pressure care are two halves of the same job.
Can bedsores be prevented?
Many bedsores can be prevented, and prevention is far easier than healing one. The core habit is regular repositioning, so no area takes unrelieved pressure for too long.
Check the skin over the bony points every day, so you catch any early change before the skin breaks.
Keep the skin clean, dry, and moisturised, and deal with incontinence or sweat promptly. Use pressure-relieving surfaces where you can, and support the person with good food and enough fluids, since well-nourished skin is more resilient. These small daily routines prevent far more sores than any treatment fixes.
When should you get medical help for a bedsore?
Get medical help if a sore is deep, getting worse, or showing signs of infection. Any sore that has broken the skin should be seen by a nurse or doctor so it can be assessed and dressed properly.
Seek help promptly if the skin around the sore is spreading red, warm, or swollen, if there is pus or a bad smell, or if the person has a fever or seems unwell.
Dark or black tissue in the sore, or a wound that is getting bigger or deeper, also needs professional care. Pressure sores can become infected, and deeper ones need proper treatment, so it is always better to ask than to wait.
The bottom line
Bedsores come from unrelieved pressure on the skin, made worse by friction, shear, and moisture, in people who cannot move freely. That is why the heart of both prevention and healing is the same simple thing: take the pressure off, again and again.
Alongside that, keep the skin clean and dry, get proper wound care, and support the body with good nutrition and fluids. Food gives the body materials to heal, working with the physical care rather than replacing it.
For more, see what to feed someone with a bedsore and which nutrients your body needs to heal a wound.