Older adults tend to have thinner skin, making them more susceptible to damage from minor pressure. They also tend to have less natural cushioning over their bones. Muscle atrophy and wasting are often common in elders especially those with paralysis. If there is loss of fat and muscle, there is no or less cushion over the bones
Add to it poor nutrition, other health conditions such as long term diabetes or spinal injuries which can reduce pain perception, you have the making of a bed sore.
Further, problems with bladder control can greatly increase risk of pressure sores because skin stays moist, making it more likely to break down. And bacteria from fecal matter not only can cause serious local infections but also can lead to life-threatening systemic complications such as sepsis, gangrene and, rarely, necrotizing fasciitis, a severe and rapidly spreading infection. Smokers tend to develop more severe wounds and heal more slowly, mainly because nicotine impairs circulation and reduces the amount of oxygen in blood, giving another reason for you to ask your loved ones to quit smoking.
If you are managing a dependent elder/patient yourself, keeping them clean (Nursing Clean!) is of utmost importance along with proper nutrition with foods rich in Proteins, Zinc and Vitamin C
Note: “Nursing Clean” is different from “Just Clean”: read elsewhere on this discussion forum.