Foot Ulcers

Foot Ulcers

Authored by Dr. Gregg Congdon

Reviewed by Dr. Kelsey Armstrong

• Overview
• Foot Ulcer Symptoms
• Progression of Foot Ulcers
• Types/Causes: Foot Ulcers
• Diagnosis of Foot Ulcers
• Treatment of Foot Ulcers
• Foot Ulcer Prevention

An open sore on the foot is a foot ulcer, which due to circumstances may fail to heal normally or recur.

Foot Ulcer Symptoms

Initially, you may not be aware that you have a foot ulcer. You may have swelling, itching or burning of the foot or notice a rash,  callus, redness, or brown discoloration of the skin. A foot ulcer may not be painful in persons who have decreased nerve sensation(s) in the lower leg. The lack of pain can be misleading.

Foot ulcers most commonly occur on the side or bottom of the foot, which is another reason why an ulcer in this location can easily go unnoticed. They can also occur on a toe. Obvious signs of a foot ulcer are a foul odor and drainage of fluid.

Progression of Foot Ulcers

Certain health conditions, such as diabetes, prevent the body from healing normally and contribute to the development of ulcers. Foot ulcers in disabled or elderly persons are often discovered by a caregiver after the ulcers have progressed. This is because of decreased sensation in their feet due to nerve damage or because of poor vision and limited flexibility, which prevents proper inspection of the feet.

At first, a foot ulcer will involve only the skin surface and often looks like a shallow red crater with a thickened, callused border. As the ulcer progresses, it will involve all the layers of the skin, the crater will deepen and the surrounding skin may begin to die (necrosis) and become infected. Eventually—after weeks, months, or even years—a foot ulcer may involve other structures, such as tendons and bones.

An infected ulcer can develop into:

• Cellulitis (widespread inflammation of skin and underlying tissue) or an abscess (pus-filled tissue)
• Osteomyelitis (bone infection)
• Gangrene (death of tissue caused by a loss of blood flow)

In the most severe foot infections, amputation of part or all of the foot or lower leg may be necessary.

Types and Causes of Foot Ulcers

The 3 common types of foot ulcers are:

• Neurotrophic or diabetic ulcers – primarily affect people with diabetes. According to the American Family Physician, diabetic ulcers are the most common foot injuries leading to lower extremity amputation. However, neurotrophic ulcers can affect anyone who has an impaired sensation of the feet. The ulcers are often caused by neuropathy, nerve damage in the feet or lower legs, which can result from decreased blood supply to the feet. The resulting oxygen depletion causes the nerve cells to shrink, or atrophy.
• Venous statis ulcers – are common in people who have recurrences of leg swelling, varicose veins, or blood clots in either the superficial or the deep veins of the legs.
• Arterial or ischemic ulcers – occur in people with poor circulation, often a result of peripheral artery disease, a condition of the blood vessels that leads to arteriosclerosis, or narrowing and hardening of the arteries, which develops when fatty deposits build up inside arteries that supply the legs and feet.

Other conditions that can decrease blood supply to the feet and cause foot ulcers include: venous insufficiency (congestion and slowing of blood circulation in the veins), kidney failure, hypertension, lymphedema (fluid buildup that causes swelling in the feet), inflammatory disease, high cholesterol, heart disease, sickle cell anemia, bowel disorders, smoking, genetics, and malignancy.

Use of some medications, such as cholesterol-reducing statins, can also lead to foot ulcers. Foot abnormalities as a result of fracture or severe arthritis may promote foot ulcer development.

Diagnosis of Foot Ulcers

The gross appearance of a foot ulcer is usually enough for diagnosis. However, your doctor will need to examine the ulcer to determine its cause and capability of healing, which will guide treatment. Be prepared to answer questions about your symptoms and medical history as well as foot hygiene.

During the physical examination, your doctor will look for signs of infection (such as redness and warmth); the size, depth, and location of the ulcer; any foot abnormalities; and problems with walking. After testing the sensation in your feet, checking your reflexes, and using a tuning fork to see if you can feel the vibration in your toes, your doctor may be able to tell whether you have neuropathy.

Your Podiatrist may also feel the pulses in your feet. Weakened pulses may indicate poor circulation, which may require further testing with Doppler ultrasound studies.

If the findings suggest an underlying condition, your Podiatrist may refer you to a specialist for further evaluation.

Tests may include any or all of the following:

• Wound culture of purulent drainage or material from the ulcer base
• Radiograph if a bone infection is suspected
• Computed tomography (CT) or magnetic resonance imaging (MRI) scans to evaluate an abscess
• Doppler or arteriographic studies to assess blood flow to feet
• Complete blood cell count
• Blood glucose and glycohemoglobin test, in patients with diabetes
• A bone scan or bone biopsy

Treatment of Foot Ulcers

The treatment of foot ulcers varies depending on its cause.

• Neurotrophic or diabetic ulcers: The main goal of treatment is to obtain wound closure. Management is guided by the severity and vascularity of the ulcer and the presence of infection. Your Podiatrist will advise you to rest and elevate the affected foot to relieve pressure.
• Venous statis ulcers: compression of the leg is used to minimize edema or swelling. This can be achieved by (wearing compression stockings),  multi-layer compression wraps, or wrapping an ACE bandage or dressing from the foot to just below the knee. The compression type is based on the ulcer’s characteristics and amount of drainage.  After ulcer closure, then compression stockings would be helpful to help control the venous insufficiency.
• Arterial or ischemic ulcers: treatment depends on how severe arterial disease is. Your doctor may recommend further testing to assess the potential for wound healing. Endovascular therapy or bypass surgery to restore circulation to the affected leg may be required.

Treatment often includes debridement (trimming away or removal) of all necrotic, callus, and fibrous tissue, which is a mainstay of ulcer therapy. After debridement, various dressings can be used depending on the state of the ulceration (a saline wet-to-dry dressing is applied). If necessary, specialized footwear or bandages to relieve pressure on the ulcerated area may be prescribed. Infected ulcers are treated with antibiotics. Management of the underlying cause of the ulcer is essential.

Foot ulcers can take weeks or months to heal, and multiple visits to a Podiatrist at Advanced Foot & Ankle Center will be required.

“Rates and speed of healing are best in ulcers that are mainly a result of neuropathy. In trials of off-loading techniques [use of customized orthotics], 21–50% of patients healed within 30 days, and 58–90% within 12 weeks…However, despite good management, healing rates in large multicentre trials were 24% at 12 weeks and 31% at 20 weeks.” (The Lancet, 2003)

For foot ulcers that do not respond to conservative therapy, a more detailed investigation is warranted to determine the cause.

Foot Ulcer Prevention

People with diabetes and others who know they are at risk for foot ulcers should examine their feet daily and practice good foot hygiene.

Those with foot ulcers should keep the wound clean and dry, change the dressing as directed, take prescribed medications, maintain a healthy diet, and wear appropriate shoes.

By controlling risk factors, such as diabetes, high blood pressure, and high cholesterol levels, you may be able to prevent foot ulcers from developing or worsening. Quitting smoking, exercising, and losing weight if you are overweight can also greatly reduce your risk of foot ulcers.