A foot ulcer is a skin sore or wound. Ulcers can occur on any part of the foot but they are more common on the sole. The skin functions as a wall that surrounds and protects the foot from harmful germs known as bacteria. A foot ulcer is like a crack in that protective wall. Once a crack occurs the foot is prone to invasion from harmful bacteria that can cause infection. The longer an ulcer remains open and untreated the greater the risk of infection.

There are approximately 1.5 million persons in Canada with diabetes. It is estimated that 15% of persons with diabetes will develop a foot ulcer. In other words 225,000 Canadian persons with diabetes will develop a foot ulcer in their lifetime. 14 – 24% of persons with diabetes and a foot ulcer will require amputation (either a partial foot amputation or a leg amputation) because the ulcer won't heal.

What causes a Foot Ulcer?

Foot ulcers are caused by excessive pressure against the skin. Pressure can be caused by an outside source such as poor fitting shoes, bed sheets or even from mattress pressure. Sources from within the feet such as thick toenails or calluses can also be a source of pressure. The skin requires blood for fuel and oxygen. Any pressure against the skin that is higher than the skin blood pressure will cut off the blood supply to the skin. Without blood the skin will begin to break down and ulcers will form. The first sign of an ulcer may be a blister.

It does not take much pressure to cause an ulcer so the skin has a built in protection system that is like a burglar alarm. Sensors in the skin detect increased pressure. When the pressure reaches a level that can cause injury an alarm is sounded. The sensors send a pain signal to the brain to alert the person to check their feet. Persons with diabetes are prone to peripheral neuropathy or loss of feeling, which is like having an alarm with broken sensors. The pressure may go unnoticed until an ulcer or even infection has occurred.

Excessive pressure can be also be likened to pressing one’s fingers against a pane of glass. After a while the fingertips turn white because the pressure from the glass cuts off the blood supply to the finger tips. Without the food and oxygen that is carried in the blood, the fingertips will starve and sores or ulcers may form. In order to protect against the harmful pressure a sensor or nerve in the finger tip will sound a pain alarm. The pain is the signal that causes the person to pull their finger away before sores or ulcers form. The pane of glass could also be thought of as poor fitting shoes, bed sheets, mattress pressure, callus or thick toenails.

Why is it necessary to seek immediate medical treatment for Foot Ulcers?

It is important to treat foot ulcers as soon as possible because the longer an ulcer remains open the greater the chance of developing an infection. Ulcers become infected when germs or bacteria enter the break in the skin and start to grow, and spread. In severe cases infection can spread into the leg. Signs that an ulcer is infected include redness, swelling, increased drainage, sudden elevations in blood sugar, fever, chills and fatigue. Pain may be lacking because of neuropathy.

Ulcer treatment begins with recognizing and eliminating the cause. Frequently the cause is harmful pressure or rubbing against the skin that goes unnoticed because of the broken skin alarm detectors. Pressure reduction or off-weighting are the terms commonly used to describe elimination of the harmful pressure. Pressure reduction may be as simple as switching shoes or it may be more involved and require orthotics, braces or casts. Antibiotics and possibly even surgery may be necessary for some ulcers. Antibiotics will not help ulcers that are not infected. Dressings and care for the wound or ulcer are also important. Some persons will be able to do their own wound care and dressing changes, whereas, other persons will need the help of nurses. The majority of foot ulcers will respond to pressure reduction and dressings.

Regardless of the treatment there are some foot ulcers that just don't heal. Persons with diabetes are often slow healers and one of the reasons for this may be because their wound healing proteins or growth factors are defective. Growth factors are proteins that play an important role in the wound healing process. Without functional growth factors an ulcer can get stuck in a non-healing phase. There are two new biological or active wound healing products on the market that are designed for non-healing diabetic ulcers: living skin equivalents (Dermagraft®) and growth factor (REGRANEX®). Dermagraft® is made from skin cells that are grown in a lab. Dermagraft® is applied to the ulcer once a week and works by replenishing the ulcer with new healthy skin cells. REGRANEX® is a form of the body's natural growth factors that is made in a lab and comes as a clear gel. It is applied to the ulcer once a day and helps to jump-start the ulcer to heal by replacing the defective growth factors. The biological products are not a substitute for good wound care and pressure reduction and should only be selected after consultation with your health care provider.

There are many issues concerning diabetes related foot ulcers including risk of infection, quality of life and fear of amputation. Rapid healing of an ulcer is important and cannot be achieved without identifying and treating the cause of the ulcer in conjunction with good wound care. Those persons with high risk feet should receive risk lowering treatments in hopes of preventing a foot ulcer.

Timothy P. Kalla, D.P.M., F.A.C.F.A.S.