A diabetic foot ulcer (DFU) is an open sore or wound on the foot that occurs as a serious complication of diabetes mellitus. These wounds range from shallow breaks in the skin to deep craters that expose bone or tendon. Developing a DFU is a common event, affecting up to one-third of all individuals with diabetes during their lifetime. Early identification of these visual characteristics is crucial for effective treatment and preventing severe outcomes like amputation.
Identifying Characteristics of Diabetic Foot Ulcers
A diabetic foot ulcer often presents as a circular, crater-like lesion, typically found on the sole or bottom of the foot. These wounds frequently develop over areas of high pressure, such as the ball of the foot, the heel, or the tips of the toes. The skin surrounding the ulcer may appear dry, red, or inflamed, and it is often encircled by a ring of thick, callused tissue.
The ulcer’s base provides clues about its severity. A healthy, healing ulcer is often pink or reddish, indicating new granulation tissue and good blood flow. Conversely, poor circulation or infection is suggested by tissue covered in yellow or white fibrous tissue (slough), or black, hardened necrotic tissue (eschar). If infected, the wound may produce a purulent, foul-smelling discharge, and the surrounding area might be noticeably warm or swollen.
A dangerous characteristic of a DFU is the lack of pain. Due to sensory neuropathy (nerve damage), individuals often do not feel the injury when it occurs, allowing it to progress unnoticed. This absence of protective sensation means ulcers are often discovered only after they become deep or show signs of infection, such as drainage. Therefore, regular, visual inspection is the only reliable method for early detection.
The Underlying Causes in Diabetes
DFU development results from a complex interplay between nerve damage, poor circulation, and mechanical stress. Chronic high blood sugar levels gradually damage the peripheral nerves, causing diabetic neuropathy. This nerve damage leads to the loss of protective sensation, meaning the feet cannot feel pain or injury, making them highly susceptible to unnoticed trauma from tight shoes or foreign objects.
Neuropathy also affects motor nerves, causing muscle weakness and imbalance that lead to foot deformities like claw toes or hammertoes. These structural changes alter weight distribution during walking, creating concentrated areas of high pressure on the sole. This repetitive, excessive pressure acts as a mechanical trigger, causing the skin to break down and form an open sore, often starting beneath a thick callus.
Many people with diabetes also suffer from peripheral arterial disease (PAD), where blood vessels in the legs and feet narrow due to atherosclerosis. Reduced blood flow (ischemia) starves the tissue of oxygen and nutrients needed for repair, meaning even minor cuts struggle to heal. The diabetic state also impairs immune cell function, reducing the body’s ability to fight bacteria. This combination transforms a simple wound into a chronic, non-healing ulcer prone to severe infection.
Immediate Steps and Medical Treatment
Once a foot ulcer is identified, immediate professional medical attention is necessary, as these wounds rarely heal without expert intervention. The first step in treatment is achieving pressure relief, known as offloading. Offloading involves completely removing weight-bearing pressure from the ulcerated area, allowing the damaged tissue to rest and begin healing.
For plantar ulcers, specialized devices like a total contact cast (TCC) or a non-removable cast walker are used to redistribute pressure across the lower leg. Concurrent with offloading, professionals perform debridement, which is the careful removal of dead, damaged, or infected tissue. This procedure eliminates a breeding ground for bacteria and exposes healthy tissue necessary for new growth.
Infection management is guided by wound cultures to identify specific bacteria. Systemic antibiotics, administered orally or intravenously, are prescribed to clear the infection and prevent spread to the bone (osteomyelitis). After debridement, the wound is dressed with advanced materials to maintain a moist environment, optimizing healing speed and quality. Proper care, offloading, and infection control must be sustained until the ulcer has fully closed.
Strategies for Preventing Recurrence
Preventing DFU formation and recurrence requires proactive, long-term self-care and professional monitoring. A foundational strategy is maintaining optimal blood glucose control, which slows the progression of nerve damage and vascular disease. Regular monitoring of hemoglobin A1C levels helps mitigate the underlying physiological mechanisms that cause ulceration.
Daily inspection of the feet is a routine for all high-risk individuals with diabetes. This involves thoroughly checking the entire foot, including the bottom and the spaces between the toes, for any signs of redness, blisters, cuts, or swelling. A small hand mirror can be used to check areas that are difficult to see. Additionally, the inside of shoes should always be checked for foreign objects or rough seams before wearing them.
Wearing properly fitted, therapeutic footwear is effective for managing mechanical stress and preventing injury. Prescription shoes and custom-molded insoles accommodate foot deformities and evenly distribute pressure across the foot’s surface, protecting high-risk areas. Regular visits with a podiatrist are also essential for routine screening, professional callus removal, and early detection of pre-ulcerative lesions.