An open sore on the foot that recurs or fails to heal normally is a foot ulcer.
Foot Ulcer Symptoms To Watch For
Initially, you may not be aware that you have a foot ulcer. You may have swelling, itching, or burning of the foot, or you may 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 in the lower leg, but this 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.
What Is The 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’s 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 (a condition called 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 of Foot Ulcers That May Develop
The three common types of foot ulcers are:
Neurotrophic or diabetic ulcers, which primarily affect people with diabetes.
“Diabetic ulcers are the most common foot injuries leading to lower extremity amputation.” (American Family Physician, 1998)
However, neurotRophic ulcers can affect anyone who has impaired sensation in their 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 recurrent 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, and are often a result of peripheral artery disease, a condition of the blood vessels that leads to arteriosclerosis, or narrowing and hardening of the arteries. Arteriosclerosis develops when fatty deposits build up inside the 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
- Lymphedema (fluid buildup that causes swelling in the feet)
- Inflammatory disease
- High cholesterol
- Heart disease
- Sickle cell anemia
- Bowel disorders
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.
How Are Foot Ulcers Diagnosed?
The appearance of a foot ulcer is usually enough for diagnosis. However, your doctor will need to examine the ulcer to determine its cause, which will determine the course of treatment. Be prepared to answer questions about your symptoms, your medical history, and your foot hygiene habits.
During the physical examination, your doctor will look for signs of infection, such as redness and warmth). Your doctor will also look at the size, depth, and location of the ulcer, and look for any foot abnormalities.
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 doctor may also feel the pulse in your feet. Weakened pulse may indicate poor circulation, which may require further testing with Doppler ultrasound studies.
If the findings suggest an underlying condition, your doctor may refer you to a specialist for further evaluation. Tests that may be conducted 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 tests, in patients with diabetes
- A bone scan or bone biopsy
How Are Foot Ulcers Treated?
The treatment of foot ulcers varies depending on the cause of the ulcer.
Neurotrophic or diabetic ulcers: The main goal of treatment is to obtain wound closure. How treatment will be managed will depend on the severity and vascularity of the ulcer and whether there is any infection. Your doctor will advise you to rest and elevate the affected foot to relieve pressure.
Venous statis ulcers: Compression is applied to the leg 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 type of compression that will be applied will depend on the ulcer’s characteristics and amount of drainage. After ulcer closure, compression stockings may help control the venous insufficiency.
Arterial or ischemic ulcers: Treatment depends on how severe the 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, callused, and fibrous tissue, which is a mainstay of ulcer therapy.
After debridement, 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 the doctor are often 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 percent of patients healed within 30 days, and 58–90 percent within 12 weeks.
However, despite good management, healing rates in large multicentre trials were 24 percent at 12 weeks and 31 percent 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 Tips You Should Consider
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.