Diabetic Foot Ulcers: What Are They and How Can You Avoid Them?

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Diabetic Foot Ulcers: What Are They and How Can You Avoid Them?

If you have diabetes, you have a higher risk of getting foot sores, or foot ulcers, as they’re often called. Between 15% and 25% of people with diabetes will have a foot ulcer. Foot ulcers can take weeks or months to heal, but if not caught and treated properly, they increase the risk of amputation. Learn more about foot ulcers and what you can do to prevent them.

What is a foot ulcer and what does it look like?

Foot ulcers are open sores or wounds that don’t heal or keep recurring. They may develop under a callus on the foot due to pressure and rubbing; they can also result from an injury or trauma to the foot. Foot ulcers usually occur on the bottom of the foot.

What causes foot ulcers?

Foot ulcers can result from several factors, such as:

Diabetic peripheral neuropathy is the main cause of foot ulcers, and this occurs due to chronically high blood sugar levels (hyperglycemia). Peripheral neuropathy can also change the way you walk, and may lead to foot deformities, such as bunions, hammertoes, and Charcot foot (a complication that affects the bones and joints in the foot, causing a deformity). A deformed foot can lead to ulcers on the ankle or bottom of the foot.

Diabetes can damage the nerves and blood vessels in the feet, leading to numbness and reduced feeling in the feet. As a result, your feet are more likely to get injured — for example, stepping on a nail or a piece of glass — and your feet may not heal well. And unless you are checking your feet regularly, you may not realize that you have a foot ulcer because you might not feel any pain.

Foot ulcers are concerning because they can quickly get infected and possibly lead to gangrene. If not caught and treated promptly, the infection can get into the muscle and the bone.

How do you know if you have a foot ulcer?

If you have a foot ulcer, you may have pain, but you might not if you have a loss of sensation in your feet. Signs of a possible foot ulcer are:

  • Drainage or blood that stains your socks or stockings or shoes
  • Redness or swelling
  • Unpleasant odor
  • Tan, brown, or black tissue, called “eschar,” that surrounds the ulcer

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Are you at risk for a foot ulcer?

Having diabetes puts you at risk for foot ulcers. Other factors that can increase the risk of foot ulcers include:

How are foot ulcers treated?

If you have — or think you might have — a foot ulcer, make sure to see your health care provider as soon as possible. Your provider will likely do the following:

  • Check for signs of infection, such as redness, warmth, swelling, discharge, or discoloration.
  • Look for blisters, cuts, scratches, or ingrown toenails (which could cause additional ulcers).
  • Check the pulses in your foot to evaluate the rate of blood flow.
  • Ask you to stand and walk to check your gait and the shape of your foot.

You may need X-rays, an MRI and/or blood tests, as well.

One way to treat a foot ulcer is debridement, which removes dead skin and tissue. This involves cleaning and disinfecting the skin around the ulcer; the wound is probed to see how deep it is and to see if there is any foreign matter in the ulcer. Dead tissue is cut away and the ulcer is cleaned out.

Once the wound is clean, special bandages and medications are applied to absorb fluid, protect the wound, and help it to heal. You might be taught to do dressing changes yourself, or you might have a visiting nurse do this for you. Ulcers will heal faster if they’re kept covered and moist. Treatment might include the use of growth factors, special dressings, and skin substitutes.

Your provider may prescribe “offloading,” which means taking weight off your foot to let it heal. This might be done with special shoes, a brace, a cast, crutches, or a wheelchair. You will likely be given oral or IV antibiotics to cure the infection, and possibly other medications, such as anticlotting medications.

Depending on how severe the foot ulcer is, you may be hospitalized. Surgery might be indicated if you have a lot of dead tissue around the ulcer, if you have peripheral arterial disease that prevents adequate blood flow to the feet, or if you have repeated ulcers due to poor alignment of bones in your feet. In severe cases, amputation may be needed to prevent the infection from spreading.

How you can prevent foot ulcers

The best defense against foot ulcers is preventing them in the first place. Here’s what you can do:

Focus on your blood sugars.

Uncontrolled blood sugars can lead to neuropathy, which can lead to loss of feeling in your feet and result in a sore or ulcer going unnoticed.

Take care of your feet.

Wash your feet every day, keep your toenails trimmed, make sure your feet stay dry and moisturized, and check your feet daily for cuts, sores, and areas of redness (notify your provider if you see that cuts aren’t healing).

Never perform “bathroom surgery.”

If you have corns or calluses, see your provider or a podiatrist. Cutting and over the counter products can damage your skin and cause an infection.

Trim toenails properly.

Trim your toenails with toenail clippers and go straight across. Don’t cut into the corners of your toenails. Have a podiatrist trim your toenails if you can’t see, feel, or reach your feet; if your toenails are thick or yellowed; or if your nails curve and grow into the skin.

Wear shoes that fit.

Make sure the shoes provide enough support and cushioning and have a wide-enough toe box so that they don’t pinch your feet. Try on shoes at the end of the day.

Don’t go barefoot.

Always wear shoes or slippers, even around the house.

Wear clean and dry socks.

Socks should wick away moisture and not be too tight or have seams that could irritate your skin.

Protect your feet from hot and cold.

Always wear shoes at the beach and on hot pavement. Keep your feet away from heaters and open fires. Avoid using hot water bottles or heating pads on your feet.

Want to learn more about keeping your feet healthy with diabetes? Read “Caring for Your Feet When You Have Diabetes,” “How to Choose Footwear” and “Improving Blood Flow to the Feet.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter, DiabeticConnect.com, and CDiabetes.com

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