“I woke up with a huge blister on my big toe, as well as smaller black blisters on two other toes. What is this from and what should I do?” This question from a DiabetesTeam member reflects a common concern: foot problems like blisters and swelling may be linked to diabetes. Another member asked, “My feet have been swelling lately. I know about sodium, but could it also be diabetes-related?”

As it turns out, it’s common for people living with type 2 diabetes to experience foot issues, such as swelling and blisters. People who also have poor circulation or diabetic neuropathy have an even higher risk of developing these foot conditions.

These problems can increase your risk of complications, which is why it’s important to act quickly and take good care of your feet. The discomfort and pain of foot problems can make it harder to get around, which could affect your quality of life while living with diabetes. Here’s a look at how diabetes can affect the feet.

How Diabetes Can Affect the Feet

In people with diabetes, foot problems are usually caused by peripheral neuropathy (nerve damage) and peripheral artery disease (PAD), which is poor blood flow. These diabetes complications can happen when high blood sugar levels damage small blood vessels and nerves over time.

Peripheral neuropathy happens when nerves outside the spinal cord and brain are damaged. With PAD, a buildup of fat and cholesterol in the arteries of the legs and arms makes it hard for the body to supply oxygen to limb tissue.

These complications of diabetes contribute to foot problems. Nerve damage from neuropathy makes it hard to notice injuries to the feet. Meanwhile, PAD decreases blood flow. Poor blood circulation means wounds don’t heal as quickly.

Diabetic Foot Conditions

Ulcers and Blisters

Open sores — commonly called ulcers — on the feet and toes develop in about 15 percent of people with diabetes. By definition, ulcers are wounds that don’t heal or that come back over and over again. “I had a foot ulcer in January, went to the hospital, and had it cut out to repair. It has been 5 months, and this hole in my foot is not healing,” one member shared.

Blisters are collections of fluid under the skin that often form due to friction. They can be caused by shoes that don’t fit well, not wearing socks, or walking a lot. Diabetic blisters are rare but most often appear on the feet and lower legs. They may also develop on the toes or hands. These look like burn blisters, but aren’t painful. They tend to heal on their own in a few weeks with blood sugar control.

People with neuropathy may not feel blisters or wounds form on their feet. Blisters and cuts can become ulcers if they are left untreated.

You may find ulcers on different parts of your foot, including:

• The bottom of your foot
• Bony parts of your foot that press against your shoe or other surfaces
• The heel
• The areas between your toes
• The tips of the toes
• The nail bed

Depending on your skin tone, ulcers may look pink, red, yellow, gray, or black. Black ulcers can be a sign of dead tissue, also known as gangrene. This happens when part of the skin or body tissue dies because it isn’t getting enough blood. Foot ulcers can come in different shapes, but they often look like craters or wedges. They can be as small as a pea or grow as large as your whole foot.

For treatment, your doctor may refer you to a podiatrist (foot specialist) or a wound specialist. In more serious cases, your doctor may refer you to other specialists.

Dry Skin

Diabetes can also lead to dry foot skin, called diabetes dry feet. This is because moisture and oil levels in the feet are affected by nerve damage. The skin on the feet can get so dry that it starts to crack and peel.

To manage dry skin on the feet, apply petroleum jelly after showering. This helps your skin hold in moisture, but make sure your feet are completely dry first. Leaving extra moisture on the skin can lead to infection.

Calluses and Corns

You may also notice calluses — patches of thick, hard skin — and corns — hard, raised bumps within irritated areas of skin. Like blisters, calluses and corns often form due to friction and pressure on the skin. On the feet, they may be caused by rubbing of shoes, walking barefoot, or poor walking posture. Calluses, specifically, tend to form faster in people with diabetes.

Corns may feel painful or uncomfortable, while calluses are usually not painful. However, both must be treated properly. Without treatment, they can turn into ulcers and may become infected. Seeing your doctor can help prevent these complications. Using a pumice stone on your feet after showering and using lotion can help prevent calluses.

Swelling and Temperature Changes

Edema (swelling) of the feet is something else you may notice. High blood sugar can slow down blood flow and make it harder for your body to manage fluids. With poor circulation, fluid may build up in your tissues, especially the lower legs and feet. This can cause uncomfortable swelling of the feet. One member noted, “I have to watch my food very carefully or else my feet swell up at night.”

Charcot foot is a rare foot complication of diabetes that can begin with swelling. It often develops in people with severe peripheral neuropathy and can progress quickly without causing pain. That’s why it can be hard to notice at first, but catching it early is very important. Untreated, it can cause the joints in your foot to collapse. Other early symptoms of Charcot foot may include pain, redness or discoloration, and a warm sensation, especially in only one foot. Poor circulation can also make your feet feel cold and may cause changes in skin color.

Fungal Infections

People living with diabetes and poor circulation have a higher risk of infection. Fungal infections in people with diabetes are most often caused by Candida albicans (a kind of yeast). If you have diabetes, you may develop athlete’s foot, a common fungal infection.

Athlete’s foot may appear on different parts of the feet, including:

• Between your toes
• The top or bottom of your foot
• The edges of your foot
• Your heels

This contagious rash can cause the skin to itch, burn, or sting. Skin may appear irritated and scaly or flaky. See your doctor if you have diabetes with itchy skin or signs of athlete’s foot.

Diabetes and Foot Care

If you have diabetes, you may develop different foot conditions. It’s important to examine your feet daily to check for cuts, blisters, and swelling. This is especially true if you’ve had reduced feeling in your feet due to neuropathy. The goal is to catch any issues early to stop them from getting worse.

If you develop any foot conditions, it’s important to see your healthcare provider. Prompt treatment will help prevent complications. Skin infections can be serious complications of ulcers in people with diabetes, and some infections can’t be treated effectively. In some cases, doctors may need to perform an amputation — surgery to remove a toe or foot — to stop the infection from spreading. Between 14 percent and 24 percent of people with diabetes will need an amputation after an ulcer.

Taking daily care of your feet — including checking for cuts or blisters, keeping them clean and moisturized, and managing your blood sugar levels — can help prevent problems before they start. Staying on top of foot health is one of the best ways to protect your mobility and overall well-being while living with diabetes.

Find Your Team

DiabetesTeam is the social network for people with diabetes and their loved ones. On DiabetesTeam, members come together to ask questions, give advice, and share their stories with others who understand life with diabetes.

Do you have diabetes that affects your feet? What foot symptoms have you noticed? Share your experience in the comments below, or start a conversation by posting on your Activities page.