Diabetes, especially poorly controlled diabetes, can cause nerve damage and poor circulation. This can lead to foot ulcers, blisters, pain, and foot infections.

In some cases, the damage can be severe. Infections in the feet can spread, damaging other organs and even becoming life threatening. Severe foot infections may mean a doctor has to amputate the foot.

While most people with diabetes do not develop severe foot complications, diabetes remains a leading cause of amputations.

Diabetes is usually caused by insulin deficiency (type 1 diabetes) or insulin resistance (type 2 diabetes). Insulin is an essential hormone responsible for helping cells absorb sugar from the blood to use for energy.

When this process does not work correctly, sugar remains circulating in the blood, causing health problems.

Prolonged periods of high sugar levels in the blood can cause nerve damage and circulation problems, which can injure the feet.

In this article, we look at foot problems that can occur in people with unmanaged or poorly managed diabetes and discuss how to prevent and manage these effects.

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The following are some foot problems people may experience:

Diabetic neuropathy

People with diabetes have a higher risk of peripheral vascular disease (PVD), especially if they do not take their medication or have difficulty controlling blood sugar. PVD occurs when fatty deposits narrow the blood vessels, reducing circulation.

PVD tends to affect blood vessels leading to and from the extremities, such as the hands and feet, reducing blood flow to both. Reduced blood flow can lead to pain, infection, and wounds that heal slowly.

Over time, peripheral vascular disease can cause nerve damage that leads to numbness in the feet. This can make it hard for people with diabetes to feel sensations in their extremities. High blood sugar also damages the nerves and interferes with their ability to send signals.

The condition also makes it difficult for a person with diabetes to feel irritation, soreness, or infection in the feet. A person may not notice when their shoes are rubbing. This lack of sensation can increase the risk of cuts, sores, and blisters. It can also delay treatment for an infection, since a person may not realize they have one.

Blisters

Diabetes increases the risk of blisters in several ways. First, diabetic neuropathy may make it more difficult for a person to know when their shoes do not fit. It may also change the way a person moves, increasing the risk of blisters.

People with diabetes may also develop a condition called bullous diabeticorum, which refers to the spontaneous formation of blisters. Doctors do not know why the blisters appear.

Blisters can become infected, causing pain and increasing the risk of an infection that spreads throughout the body.

Diabetic ulcers

About 7% of people with peripheral neuropathy develop diabetic foot ulcers each year. A combination of poor circulation and nerve damage means that a person may not notice the ulcers until they are severe. Weak circulation can also slow healing. Left untreated, ulcers can damage the foot and become infected.

Ulcers may also make walking very painful. Shoes and socks may intensify ulcer symptoms.

Diabetic calluses

Calluses are areas of hard, thickened skin cells. Large calluses on the feet can make it hard to walk and may change how shoes fit. The primary issue with calluses is that they increase the risk of ulcers and infections. Keeping calluses clean and removing them when necessary is important for protecting the feet.

Foot infections

Diabetic ulcers can become infected, especially if a person does not treat them or keep them clean. These infections may spread to the bloodstream, damaging organs and endangering a person’s life.

A person may also experience gangrene, which causes tissue death and may lead to amputation.

Foot infections can damage the underlying structures of the foot, including the bones. Poor circulation also damages underlying structures. This can change the shape of the foot, causing further pain and difficulty walking. Doctors call this Charcot foot.

Charcot foot increases the risk of developing more ulcers.

Amputation

Diabetic foot problems can lead to serious infections. To prevent an infection from spreading and minimize damage to nearby regions such as the legs, a doctor may recommend amputation. Amputation means removing a part of the body, such as a toe, foot, or portion of the leg.

Diabetes is a leading cause of amputations. A 2020 study estimates that it plays a role in 25–90% of amputations occurring within studied groups of people.

Death

Severe diabetic foot problems can be life threatening, especially when an infection spreads. Having foot problems severe enough to require amputation is a major risk factor for death, even when a doctor amputates the foot to prevent the infection from spreading.

A 2021 study estimates that the 5-year survival rate following amputation because of a foot infection is just 43%.

Foot symptoms of diabetes vary from person to person and may depend on the specific issues a person is experiencing at the time.

However, symptoms might include:

  • loss of feeling
  • numbness or tingling
  • blisters or other wounds without pain
  • skin discoloration and temperature changes
  • red streaks
  • wounds with or without drainage
  • painful tingling
  • staining on socks

If an infection develops, a person may also experience some of the following:

  • fever
  • feeling very sick
  • chills
  • uncontrollable blood sugar
  • shaking
  • shock
  • redness

Any person with diabetes who experiences symptoms of an infection, especially on the feet, should seek emergency treatment.

Diabetic neuropathy and peripheral vascular disease are serious conditions that a doctor must monitor closely.

Both cause complications that can have serious, ongoing effects. These complications may include:

  • foot ulcers or wounds that do not heal
  • infections, including skin infections, bone infections, and abscesses
  • gangrene, when an infection causes tissue death
  • foot deformity
  • Charcot foot, which alters the shape of the feet as bones in the foot and toe shift or break
  • death
  • damage to surrounding structures, such as the legs

Sometimes, doctors can reverse complications, such as infections. However, other complications, including gangrene, may lead to permanent physical changes.

A doctor may recommend amputation if a person develops gangrene.

Read more about gangrene here.

People who have diabetes should see a doctor regularly as part of their care. A doctor may recommend specific foot care, including daily foot exams.

Anyone who notices any of the following changes should seek immediate medical attention:

  • changes in skin color on the foot
  • swelling in the foot or ankle
  • temperature changes in the feet
  • persistent sores on the feet
  • pain or tingling in the feet or ankles
  • ingrown toenails
  • athlete’s foot or other fungal infections of the feet
  • dry, cracked skin on the heels
  • signs of infection

In diagnosing diabetic foot problems, a doctor may:

  • ask about recent changes in the feet
  • check blood glucose
  • perform X-rays to look for damage to underlying structures
  • test for nerve damage and sensation
  • do bloodwork to look for signs of systemic infection

Treatment for diabetic foot problems varies according to the severity of the condition. A range of surgical and nonsurgical options may help.

Nonsurgical treatment

A doctor will first attempt to treat diabetic foot problems without using surgery. Some methods include:

  • keeping wounds clean and dressed
  • prescribing antibiotics to treat infections
  • removing calluses
  • prescribing immobilization devices, such as a walking cast or total contact cast
  • closely observing any gangrene on the toes until self-amputation occurs, which is when the toes fall off due to lack of blood flow
  • recommending exercises and diet changes to manage peripheral vascular disease and prevent it from getting worse

Surgical treatment

When nonsurgical treatment does not successfully heal diabetic foot problems, a doctor might consider surgery. Surgical options include:

  • removing decaying or dead tissue
  • removing ingrown toenails
  • amputating the affected limb, which may range from a single toe to the leg above the knee
  • surgically stabilizing Charcot Foot
  • performing an arterial bypass for peripheral vascular disease, which assists blood flow to the area
  • performing endovascular surgery with placement of stents, which are small devices that keep blood vessels open

Preventing foot problems is essential for people who have diabetes. Keeping feet healthy is critical, and a person should be vigilant about foot hygiene. An individual can take the following steps:

  • Check the feet each day: Examine the feet daily or ask someone to check for any changes or injuries.
  • Wash the feet daily: Keep the feet clean to prevent infections.
  • Wear supportive shoes and socks: Protect the feet in socks and shoes at all times. A podiatrist may recommend special shoes to help prevent deformities. Do not apply socks so tightly that they restrict blood flow.
  • Promote blood flow to the feet: Put the feet up when sitting, wiggle the toes periodically, and get enough exercise. These actions help promote healthy blood flow to the feet.
  • Trim nails carefully: Trim toenails straight across and keep them short. Rounded nails can grow inward, leading to infection.
  • Care for corns and bunions: Treat corns and bunions carefully. Never shave corns, as this increases the risk of infection.
  • Protect feet from extreme temperatures: Exposure to extreme hot and cold can damage the feet of people with diabetes.
  • Receive regular examinations on the feet: Regular examinations by a doctor are key to preventing infections, amputations, and severe deformities.
  • Control blood sugar: Uncontrolled blood sugars increase the risk of podiatric complications from diabetes.
  • Avoid smoking: Smoking adversely affects blood flow to the tissues, making foot problems worse in people with diabetes.

Learn more about whether people with diabetes can soak their feet in salts here.

Diabetes can cause serious foot problems that can result in foot or limb loss, deformity, and infection. However, a person can prevent or minimize many of these problems.

While controlling blood sugar by following the recommended diabetes treatment plans is the best way to prevent these serious problems, self-care and regular checkups with a doctor can also help prevent problems from developing.

Foot problems in diabetes can occur due to restricted blood flow and unnoticed cuts and infections that develop due to numbness in the area.

A person with diabetes should have regular podiatric checks to ensure that any foot problems do not cause complications.

A doctor will treat the feet using sterilization, observation, and, possibly, immobilization devices, such as a walking boot. If these are not effective, they might recommend surgery to remove infected tissue that has the potential to spread.

This might require amputation.

People with diabetes should keep their feet clean, undergo regular monitoring, and put on supportive footwear to minimize complications and foot issues.

Q:

What other areas does diabetes affect in the body?

Anonymous

A:

When diabetes is not well controlled, long-term complications can develop and affect many different areas of the body.

Uncontrolled blood sugar can cause blood vessel injury that can lead to cardiovascular disease, kidney damage, nerve injury in the extremities, and eye problems. Diabetes can also make a person more susceptible to skin infections.

Elaine K. Luo, MDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.