Pressure ulcers are sores resulting from prolonged pressure on the skin.
Developing in stages from tender sections of reddened skin to deep wounds impacting deeper tissues and muscle, pressure ulcers typically develop on bony sections of the body left in contact with a bed, wheelchair, or other resting surface over a lengthy period of time–including your feet and ankles.
Foot and ankle pressure ulcers typically occur in patients already suffering from another medical condition, one which either keeps them immobile or render them unable to feel the pain of a developing wound.
What Causes Pressure Ulcers?
Pressure against the bony parts of your foot like the ankle, ball of your foot, or heel, where the tissue might be compressed between bone and the resting surface, can result in reduced blood flow through the affected tissues. This in turn can allow the skin to become damaged or die outright from a lack of oxygen and nutrients.
More specifically, doctors point to three types of force usually involved in the development of pressure ulcers.
- Pressure. Constant pressure from the weight of the body resting on the same surface for prolonged periods of time is key in most cases of a pressure ulcer. Even in mild cases where the skin and other tissues do not die, inconsistent blood flow can weaken the tissues and make them more susceptible to injury from the other forces.
- Friction. Skin rubbing against other surfaces can, over time, weaken the surface of the skin and make it susceptible to wounds. Enough friction over time can remove protective outer layers of skin, exposing skin which is susceptible to infection and more serious injury to the surface.
- Shear. Shear occurs when forces act to pull your skin in two different directions at once. For example, your foot sliding in an ill-fitting shoe may result in skin near the surface being pulled in one direction while deeper skin pulls in another direction. Over time, or in skin already weakened by other injuries, this can cause wounds beneath the surface which develop into ulcers.
Pressure ulcers on the foot usually aren’t a problem in wheelchair bound patients, but are very common in patients who are confined to a bed and patients who cannot feel their extremities well.
Symptoms and Warning Signs
Pressure ulcers develop in stages, and often in patients who cannot feel them, so usually the first symptom a patient notices is the presence of a fully formed pressure ulcer. Early warning signs to be alert to before the formation of a pressure ulcer include:
- Changes in skin. Any change in the skin could preface the development of a pressure ulcer; changes in color, in texture, in skin temperature, and in sensitivity all arise. The exact details will depend on how the ulcer has formed; friction will make skin raw and red, while shear-induced ulcers may result in bruising while leaving the surface intact.
- Swelling. Swelling in bony areas of the foot should be taken as a major warning sign, as it typically indicates at least minor damage in the underlying tissues..
- Drainage. Patients or caretakers may only notice ulcers due to the presence of drainage on socks or sheets. Drainage can also preface full ulceration, if the injury begins below the surface.
Each of these should be treated urgently, as doing so can prevent the full formation of pressure ulcers. Even in cases which do not develop later into pressure ulcers, these symptoms should be treated as a warning to maintain better habits of adjustment and inspection.
Risk Factors
The risk factors for pressure ulcers are relatively straightforward:
- Immobility. Patients with no or limited movement are far more susceptible to pressure ulcers than patients who can get up and move around.
- Poor nutrition. Allows skin condition to deteriorate faster and more severely when injured.
- Impaired perception of skin. Allows ulcers to fully form or develop in severity without being noticed by patients. Foot ulcers are common with peripheral neuropathy from diabetes, for example.
- Health problems effecting blood flow. Patients who are already prone to poor blood flow must be especially careful about maintaining blood flow when confined to a bed. Some patients may even need to take care with how tight they lace shoes.
Avoiding Pressure Ulcers
To prevent pressure ulcers as a patient or caretaker, keep these points in mind.
- Mobility. Even minor adjustment of seating or resting position throughout the day can prevent bedsores from forming through immobility.
- Skin care. Hygiene, moisturizing, and other skin care activities can greatly protect against pressure ulcers.
- Nutrition. Good nutrition allows skin susceptible to pressure ulcers to recover quickly and efficiently instead of deteriorating.
- Cushioning. Good cushioning and bedding can reduce the exposure of patients to the three forces responsible for pressure ulcers, when immobile, as can well-fitted socks and shoes in mobile patients susceptible to ulceration.
- Inspection. Inspecting regularly for pressure ulcers can help prevent them from forming and reduce their severity should they occur.
Seeing a Doctor
Untreated pressure ulcers can lead to serious, life-threatening complications including infections, sepsis, and certain forms of cancer. If you notice pressure ulcers forming, it’s usually a good idea to check in with a doctor for further instruction—even if they already seem to be healing.