Diabetes mellitus (DM) represents several diseases in which high blood glucose levels over time can damage the nerves, kidneys, eyes, and blood vessels. Diabetes can also decrease the body’s ability to fight infection.
When diabetes is not well controlled, damage to the organs and impairment of the immune system is likely. Foot problems commonly develop in people with diabetes and can quickly become serious.
With damage to the nervous system, a person with diabetes may not be able to feel his or her feet properly. Normal sweat secretion and oil production that lubricates the skin of the foot is impaired.
These factors together can lead to abnormal pressure on the skin, bones, and joints of the foot during walking and can lead to breakdown of the skin of the foot. Sores may develop.
Damage to blood vessels and impairment of the immune system from diabetes make it difficult to heal these wounds. Bacterial infection of the skin, connective tissues, muscles, and bones can then occur. These infections can develop into gangrene.
Because of the poor blood flow, antibiotics cannot get to the site of the infection easily. Often, the only treatment for this is amputation of the foot or leg. If the infection spreads to the bloodstream, this process can be life-threatening.
People with diabetes must be fully aware of how to prevent foot problems before they occur, to recognize problems early, and to seek the right treatment when problems do occur.
Although treatment for diabetic foot problems has improved, prevention – including good control of blood sugar level – remains the best way to prevent diabetic complications.
People with diabetes should learn how to examine their own feet and how to recognize the early signs and symptoms of diabetic foot problems.
They should also learn what is reasonable to manage routine at home foot care, how to recognize when to call the doctor, and how to recognize when a problem has become serious enough to seek emergency treatment.
Diabetes and foot problems facts
Two main conditions, peripheral artery disease (PAD) and peripheral neuropathy, are responsible for the increased risk of foot problems in people with diabetes.
People with diabetes have an increased risk of ulcers and damage to the feet.
A number of different kinds of foot problems can occur in people with diabetes. These include bunions, corns, calluses, hammertoes, fungal infections, dryness of the skin, and ingrown toenails.
Treatment depends on the exact type of foot problem. Surgery may be required for some cases.
Gangrene (dry gangrene) is tissue death due to absence of blood circulation. It can be life-threatening if bacterial infection develops (wet gangrene).
Many diabetes-related foot problems can be prevented by good control of blood sugar levels combined with appropriate care of the feet.
How can diabetes cause foot problems?
Both type 1 and type 2 diabetes cause damage to blood vessels and peripheral nerves that can result in problems in the legs and feet. Two main conditions, 1) peripheral artery disease (PAD), and 2) peripheral neuropathy are responsible for the increased risk of foot problems in people with diabetes.
Peripheral artery disease (PAD), sometimes referred to as peripheral vascular disease (PVD), means that there is narrowing or occlusion by atherosclerotic plaques of arteries outside of the heart and brain. This is sometimes referred to as “hardening” of the arteries.
Diabetes is a known risk factor for developing peripheral artery disease. In addition to pain in the calves during exercise (medically known as intermittent claudication), the signs and symptoms of peripheral artery disease relate to a decreased delivery of oxygen to the lower legs and feet.
In severe cases, the lack of oxygen delivery to tissues can result in ulcers and even gangrene (tissue death).
Peripheral neuropathy refers to damage to the peripheral nerves directly as a result of diabetes. Symptoms of peripheral neuropathy include decreased sensation in the nerves of the legs and feet, making it difficult to perceive injuries due to lack of feeling.
Peripheral neuropathy also causes a tingling, pain, or burning in the involved areas. It can also cause the muscles of the feet to work improperly, leading to misalignment of the foot that can put pressure on certain areas of the foot.
What are examples and symptoms of foot problems caused by diabetes?
In the most severe case, as mentioned above, due to a combination of decreased sensation and reduced blood flow to the feet, ulcers may develop. If the tissues continue to receive insufficient oxygen, tissue death (gangrene) occurs.
Gangrene is a serious and potentially life-threatening condition. Other potentially serious problems that may develop include cellulitis (infection of the tissues beneath the skin) and osteomyelitis (infection of the bone); sepsis (the infection spreads to the bloodstream) also is possible.
People with diabetes are at increased risk for milder problems with the feet that are not specific to diabetes but may occur more frequently due to problems with the nerves and circulation to the feet.
Some of these conditions are:
- Calluses and corns, that may develop due to abnormal alignment of the feet or abnormal gait
- Fungal infections of the nails, which can appear as thickened, discolored, and at times brittle nails
- Tinea pedis, or athlete’s foot, a fungal infection of the skin of the feet
- Hammertoes, or bent toes due to muscle weakness.
- Bunions, or the angling of the big toe toward the second toe. The area of the bunion may become reddened and irritated, leading to callus formation.
- Ingrown toenails
- Cracking of the skin of the feet, especially the heels, due to dry skin
Diabetic Foot Care Causes
Several risk factors increase a person with diabetes chances of developing foot problems and diabetic infections in the legs and feet.
Footwear: Poorly fitting shoes are a common cause of diabetic foot problems.
If the patient has red spots, sore spots, blisters, corns, calluses, or consistent pain associated with wearing shoes, new properly fitting footwear must be obtained as soon as possible.
If the patient has common foot abnormalities such as flat feet, bunions, or hammertoes, prescription shoes or shoe inserts may be necessary.
Nerve damage: People with long-standing or poorly controlled diabetes are at risk for having damage to the nerves in their feet. The medical term for this is peripheral neuropathy.
Because of the nerve damage, the patient may be unable to feel their feet normally. Also, they may be unable to sense the position of their feet and toes while walking and balancing. With normal nerves, a person can usually sense if their shoes are rubbing on the feet or if one part of the foot is becoming strained while walking.
A person with diabetes may not properly sense minor injuries (such as cuts, scrapes, blisters), signs of abnormal wear and tear (that turn into calluses and corns), and foot strain. Normally, people can feel if there is a stone in their shoe, then remove it immediately. A person who has diabetes may not be able to perceive a stone. Its constant rubbing can easily create a sore.
Poor circulation: Especially when poorly controlled, diabetes can lead to accelerated hardening of the arteries or atherosclerosis. When blood flow to injured tissues is poor, healing does not occur properly.
Trauma to the foot: Any trauma to the foot can increase the risk for a more serious problem to develop.
Athlete’s foot, a fungal infection of the skin or toenails, can lead to more serious bacterial infections and should be treated promptly.
Ingrown toenails should be handled right away by a foot specialist. Toenail fungus should also be treated.
Smoking: Smoking any form of tobacco causes damage to the small blood vessels in the feet and legs. This damage can disrupt the healing process and is a major risk factor for infections and amputations. The importance of smoking cessation cannot be overemphasized.
How are foot problems caused by diabetes treated?
Treatment depends upon the type of foot problem. For example, some problems such as corns may require wearing corrective shoes, while others such as mild infections may be treated with antibiotics or antifungals.
Other problems may need surgical debridement and antibiotics. Gangrene, or tissue death, cannot be reversed, but treatments are available to prevent gangrene (often termed dry gangrene) from spreading or becoming infected (dry gangrene becomes infected and develops into wet gangrene).
Surgical removal of the dead tissue is typically required, and antibiotics are given to prevent the development of life-threatening infections in the dead tissue. In severe cases of gangrene, amputation of the affected part may be necessary.
Other types of foot problems can be relieved by proper footwear, sometimes with orthotic devices, and splinting or bracing. For some conditions like hammertoes, bunions, and ingrown toenails; surgery may be necessary to correct severe cases.
Taking proper care of your feet (see Prevention section) can help prevent or relieve many common foot problems in people with diabetes.
Can diabetes-related foot problems be prevented?
Some diabetes foot-related problems can be prevented by taking careful steps to observe and care for your feet.
Keeping blood sugar levels under control (in the ranges advised by your doctor), and following your recommended diet and exercise program are the best way to prevent all complications of diabetes, including foot problems. In addition to keeping your diabetes under control, you can take steps to care for your feet, including the following:
- Wear comfortable, closed-toe footwear at all times. Special shoes are available for people with bunions or foot deformities if these are necessary. Be sure no objects are trapped inside the shoes that could cut or injure your feet.
- Don’t walk barefoot, even at home. Be sure your feet do not get burned by walking on very hot pavement in summer
- Always wash your feet with warm water and dry them well after washing.
- Check your feet daily for any sores or problems.
- Apply lotion to dry areas, especially heels, but don’t use lotion between the toes. Corns and calluses can be lightly smoothed with a pumice stone. Never use scissors or razors to cut away corns or calluses.
- Trim toenails straight across, and do not cut the corners shorter than the rest of the nail.
- Be sure that your doctor checks your feet at every checkup.
- Stop smoking, if you are a smoker. Smoking further increases the risk of arteriosclerosis and poor circulation to the feet.
What is the prognosis for diabetes-related foot problems?
The outlook depends upon the severity of the foot problem. As mentioned before, gangrene can be life-threatening if bacterial infection develops in the dead tissue area. Severe gangrene may result in the necessity for amputation of the affected area.
Other foot problems are less severe but may nevertheless lead to reduced function or discomfort.
Patients need to understand that for the best outcome of foot problems caused by diabetes is life-long monitoring of their feet for problems and consulting their doctor immediately if a problem begins to develop.