By Dr. Steven Gershman, DPM
The underlying causes of most diabetic foot ulcers are neuropathy, causing poor or no sensation, poor circulation, deformities in the feet causing hot spots or areas of pressure or rubbing in the shoes or on the floor, and trauma.
Now what is an ulcer? It is a wound or hole in the skin that occurs when the skin is damaged and breaks down. The outer layers of the skin initially wear or slough off. If left untreated, the ulcer can reach deeper into the fat, muscle or bone which is why it’s important to prevent diabetic foot ulcers. The most common areas to develop an ulcer on the feet is the sole. Some ulcers become infected which adds to the damage and danger.
What causes diabetic foot ulcers?
Neuropathy is by far the biggest issue in the occurrence of diabetic foot ulcers. Neuropathy basically means damage to the nerves leading to the feet. The reduction or loss of feeling caused by neuropathy leads to the inability to recognize areas of irritation or pressure spots on the feet. This is called loss of protective sensation. If the foot is subject to constant irritation or pressure, eventually the skin is damaged and breaks down, leading to an ulcer. To reduce the risk of neuropathy and its intensity and to prevent neuropathy and diabetic foot ulcers, you need to control the glucose or sugar. As the a1c rises from the increased glucose, the nerves are damaged more and more, leading to pain or the loss of sensation and in extreme cases complete lack of feeling in the feet. This is the number one cause of diabetic foot ulcers.
Poor circulation can lead to foot ulcers and more importantly is the main issue in poor healing of ulcers. Blood is the key factor in healing wounds and as circulation is diminished, the ability to heal is reduced. Reduced circulation can be either in the large blood vessels in the legs and feet or in the small blood vessels in the skin called the microcirculation or a combination of both. Either way, the tissue is not getting enough blood to heal and be healthy.
There are many causes of poor circulation. The good news is that there are a few things you can do to keep your circulation under control and prevent diabetic foot ulcers. Keeping the glucose, cholesterol and triglycerides under control, exercising and not smoking are major factors that can help with improving circulation. Diet has a significant effect on both sugar and fats (cholesterol and triglycerides) and your doctor can prescribe medication to help. The fats in your diet and body can block the arteries, reducing blood flow. Increased sugar can damage the lining of the arteries which carry the blood. Exercise helps increase the blood flow and create new blood vessels. Talk to your doctor before starting a new exercise program. And of course, smoking is the single most damaging factor to blood vessels. It causes an immediate clamping down of the small vessels, reducing flow and long-term damage to all the vessels. Stopping smoking is a huge factor in improving circulation and general health.
Foot deformities. The most common deformities on the feet are at the forefoot where bunions and hammertoes occur. Bunions are bumps on the big toe side of the forefoot. Often the big toe is deviated toward the 2nd toe. The bump on the side of the foot becomes a risk for shoe irritation. A bunion is bone so it doesn't give when pressured by the shoe. Most shoes aren't wide enough to handle a large bunion. As a result, the skin over the bump can open and form a wound or ulcer. A tailor's bunion is a bunion on the side of the little toe. It often mirrors the big toe bunion. Many people have both. Again, the bump on the little toe side can be irritated by the shoe causing an ulcer.
Hammertoes are deformities to the toes causing them to buckle with the toe sticking up in the air higher than the foot unlike than a normal toe which is straight and flat. The top of the toe is often irritated by the toe box of the shoe as regular shoes often don't have much room in the toe box. The constant rubbing leads to ulcers on the top of the toes or sometimes at the tip of the toes where they rub on the bottom of the shoe.
In addition, sometimes when the shoe has a tight toe box the toes are jammed together, especially if there are bunions. This can cause ulcers on the sides of the toes where they butt into each other. Hammertoes can cause back pressure on the bottom of the ball-of-the-foot. This pressure can lead to ulcers on the bottom of the foot.
In some people the metatarsal bones that make up the forefoot can be uneven leading to isolated areas of pressure on the bottom of the foot. This is a common cause of calluses which can lead to ulcers.
Other areas of deformities leading to ulcers are the heel when the normal fat pad is thinner than normal due to years of overuse. Also, the outside of the foot at the midfoot where there is a normal protuberance sticking out, can be irritated and ulcerate. Some people also have collapsed arches leading to flat foot and bony outgrowths that can ulcerate.
So how do you prevent diabetic foot ulcers when you have deformities?
Shoes, shoes, shoes---. It’s all about the shoes. Wearing regular shoes, most commonly found in shoe stores exacerbate foot problems and increase the risk of developing ulcers. The best shoes for diabetic ulcers are diabetic shoes that are specially designed with wider and deeper toe boxes to accommodate the deformities listed above. The extra room reduces the irritation to the feet and toes which causes the ulcers and helps with diabetic foot ulcer prevention. Also, the leather is softer and gives. The diabetic shoe also comes in multiple widths including extra extra wide to accommodate most deformities. In severe cases, custom made shoes may be necessary. These are made from a mold of the foot.
The second important factor in the shoes to reduce the risk of an ulcer is the insole. Diabetic insoles are specially made to support the arch and off load any bony protuberances. Off-loading means to create space around a bony area that sticks out, so it won’t be irritated. The top layer of the diabetic insole is made of a special material that molds to the foot over time to protect it. Also, the material breaks down before the skin in many cases which reduces the risk of ulcer.
Wearing diabetic shoes and insoles like the ones offered by Orthofeet is a big step in the right direction that can help prevent foot ulcers from happening in the first place. Orthofeet offers a large selection of women’s and men’s styles such as diabetic sneakers, diabetic boots, diabetic sandals and more. To learn about Orthofeet diabetic shoes and view the collection, click here.
Trauma can include simply jamming your feet or toes specifically into hard objects such as furniture. This is quite common and without shoes to protect the feet, can lead to fractures and later new deformities especially to the toes. Trauma also includes minor daily micro trauma such as poorly fitting shoes that damage toenails, causing ingrown nails as well as thick hard to cut nails. Wearing shoes all the time when on your feet can reduce the risk of trauma and later diabetic foot ulcers. Correct fitting diabetic shoes with diabetic insoles are the best way to go and prevent diabetic foot ulcers from occurring.
Other tips for diabetic foot ulcer prevention
Check your feet daily. Ulcers usually have a precursor such as callus formation, red areas, blisters, swelling, blood on the socks. If you check your feet every day you have a good chance of preventing the diabetic foot ulcer if you act immediately. Checking your feet yourself can be hard for some people. A mirror to see the bottom or a cell phone picture with a selfie stick will allow you to visualize the all-important bottom of the feet. You can also have a family member or other support person do this for you. The key is then to act immediately if you see something suspicious. When in doubt don't wait. Call your podiatrist or other medical provider as soon as possible. One day later can lead to an infection or worsening ulcer. The faster you act the better the outcome.
Control your sugar. The higher the sugar, the greater risk of ulcer and subsequent infection. As the sugar rises it damages the collagen that is the cement holding the skin together. The skin becomes weaker and is more prone to ulceration. Also, the higher sugar weakens the local immune system that fights infection.
Apply moisturizing cream to the feet daily. Moist skin is softer and better able to fight off diabetic foot ulcers. Dry cracking skin ulcerates easier.
Don't try and treat calluses by yourself. Don't ever use a sharp object to cut off the callus. Let your podiatrist or medical professional treat it. Also, your podiatrist can diagnose the underlying cause of the callus and treat it. Many calluses can be treated by proper diabetic shoes and insoles. Don't ever use over the counter corn remover pads with acid in them. They can burn a hole in your foot causing an ulcer. Finally, remember just like managing diabetes, preventing diabetic foot ulcers is a long-term lifelong commitment. The good news is it is doable and by following the tips for diabetic ulcer prevention, you will keep your feet for life.