Foot ulcers are open sores that develop on the feet and ankles, often failing to heal or recurring. They result from the breakdown of skin and underlying tissues, making the area vulnerable to infection. Foot ulcers can cause pain and may make walking difficult, especially for individuals with certain underlying health conditions.
Nerve Damage
Nerve damage, known as neuropathy, is a primary cause of foot ulcers, especially in individuals with diabetes. High blood sugar levels associated with diabetes can damage the small blood vessels that supply oxygen and nutrients to the nerves, leading to nerve damage over time. This damage often results in a loss of sensation in the feet, making it hard to detect minor injuries, pressure points, or even ill-fitting footwear.
When sensation is impaired, cuts, scrapes, blisters, or prolonged pressure may go unnoticed, allowing minor trauma to progress into an ulcer. Without protective pain sensation, these injuries can worsen and break down the skin and underlying tissues, forming an ulcer. Neuropathy can also affect motor nerves, leading to muscle weakness and foot deformities like claw toes, creating additional pressure points prone to ulceration.
Blood Flow Problems
Insufficient blood supply to the feet, known as ischemia, is another major contributor to foot ulcers. This often stems from peripheral artery disease (PAD), where fatty deposits like cholesterol build up and narrow the arteries, restricting blood flow. Reduced blood flow means affected tissues receive inadequate oxygen and nutrients, making them susceptible to breakdown and hindering natural healing.
When an injury occurs, poor circulation prevents infection-fighting cells and healing factors from reaching the wound effectively. This impaired delivery causes wounds to heal slowly or not at all, increasing the risk of infection and further tissue damage. Arterial ulcers are painful open wounds that develop due to compromised blood circulation and often appear on the toes, heels, or other pressure points.
Direct Pressure and Injury
Direct external factors, such as sustained pressure and minor trauma, can initiate the ulceration process, particularly when combined with underlying nerve damage or poor circulation. Prolonged pressure on specific areas of the foot can exceed the capillary closing pressure, leading to ischemia and tissue necrosis. This can occur from ill-fitting shoes, prolonged standing, or bony prominences rubbing against surfaces.
Friction or repeated mechanical stress can also contribute to skin breakdown and ulcer formation. Even minor injuries like cuts, scrapes, or blisters can become significant if they go unnoticed or fail to heal due to compromised sensation or blood flow. In individuals with neuropathy, the absence of pain signals means these small injuries may not be addressed promptly, allowing them to deepen and become chronic ulcers.
Other Contributing Conditions
Several other medical conditions and lifestyle factors can contribute to the development of foot ulcers. Kidney disease can lead to chronic swelling (edema) in the feet, which can compromise skin integrity and increase the risk of breakdown. Certain autoimmune diseases, where the immune system mistakenly attacks healthy cells, can cause inflammation of blood vessels or affect skin and connective tissue, potentially leading to ulcers.
Infections can also complicate existing wounds, preventing healing and potentially spreading to deeper tissues or even bone if left untreated. Lifestyle choices like smoking worsen circulation by damaging blood vessels and impeding blood flow, increasing the risk of ulcer formation and hindering wound healing. Obesity and a history of previous foot problems can also predispose individuals to developing foot ulcers.