Diabetic Foot - Causes and Symptoms

Diabetic foot is a term that encompasses the diseases and alterations that frequently occur in patients with diabetes mellitus. Diabetic foot, if not recognized and treated in time, can progress to severe complications, provoking from the formation of deep and extensive ulcers to the need for amputation of the foot.

Diabetic foot ulcer
Diabetic foot ulcer

What is diabetic foot?

Diabetes mellitus is a serious, slow-evolving disease that if not properly controlled causes numerous lesions throughout the body.

The so-called diabetic foot is one of the most common complications in diabetic patients and is the end result of a set of changes that diabetes causes in the lower limbs, including nerve damage, changes in arterial circulation, reduced immunity and changes in the anatomy of bones of the foot. Let's explain:

Chronic elevated glucose levels cause damage to the peripheral nerves, leading to a condition called diabetic neuropathy. The patient with diabetic neuropathy can lose the normal sensitivity of the feet, having difficulty to feel pain and correctly distributing the weight of the body on the feet. These factors can lead to abnormal pressure in the regions of the feet during walking, making it easy to develop callous pressure points and injuries to the skin, soft tissues, bones and joints. Ulcers may arise if care is not taken with the diabetic patient's feet.

Diabetic neuropathy may also weaken certain muscles in the feet, further contributing to deformity in the feet. Over time, repeated injuries to the bones and joints can dramatically alter the anatomy of the foot, creating a vicious cycle where each new injury favors the appearance of others.

Another important factor in the development of diabetic foot is the injury of the blood vessels that nourish the feet. Chronically poorly controlled diabetes causes damage to the arteries of the lower limbs, decreasing the flow of blood to the feet. This poor circulation can cause skin ischemia, contributing to the formation of ulcers and impairing the healing of wounds.

In some patients the vascular injury is so severe that parts of the foot become ischemic, evolving into gangrene. About 5% of diabetics eventually need to amputate a finger, or even the entire foot, due to this complication.

The third factor for the appearance of diabetic foot is the compromised immune system that occurs in diabetes, facilitating the occurrence of infections and making it difficult to heal wounds. Because of poor blood circulation, antibiotics may not reach the site of infection properly, with the risk of infection spreading into the bloodstream, causing sepsis.

Patients with diabetes should learn to analyze their own feet and know how to recognize the first signs and symptoms of diabetic foot problems.

Risk factors

Early recognition and management of risk factors are important in reducing the occurrence of severe foot ulcerations and injuries.

The main risk factor is poorly controlled diabetes, because persistently high levels of glucose are responsible for the changes that lead to the onset of diabetic foot.

Other important risk factors have already been presented: neuropathy, foot deformities and signs of vascular disease. All three can be identified through a careful physical examination of the lower limbs. Among these, neuropathy seems to be the most important in the development of diabetic foot. About 80% of patients with foot ulcers have lesions on their peripheral nerves.

The use of shoes not suitable for diabetics also increases the risk of complications, especially if the patient has red spots, sore spots, blisters, calluses, flat feet, bunions or frequent pain associated with wearing shoes.

Cigarette smoking is another important problem because tobacco causes damage to small blood vessels in the feet and legs, favoring the progression of vascular injury and making it difficult to cure existing skin lesions.


Every diabetic patient should be questioned during the consultations if they feel any discomfort in their legs or feet. If the answer is yes, other questions should be asked to assess the severity of the condition:

What do you feel in your feet?
  • a) Burning, numbness or tingling (2 points)
  • b) Tiredness, cramps or pain (1 point)

What is the location of the symptoms?
  • a) Feet (2 points)
  • b) Calves (1 point)
  • c) Other places (without points)

Have the symptoms woken you at night?
  • a) Yes (1 point)
  • b) No (without points)

When do symptoms appear?
  • a) Worst night (2 points)
  • b) Present day and night (1 point)
  • c) Only present during the day (no points)

What relieves the symptoms?
  • a) Walking (2 points)
  • b) Standing (1 point)
  • c) Sit, lie down or do not relieve anything (no stitches)

The total score of symptoms can determine the severity of the neuropathy:
  • 0 to 2 - Normal
  • 3 to 4 - Slight
  • 5 to 6 - Moderate
  • 7 to 9 - Severe

Some simple clues may point to circulatory problems: weak pulse in the feet, cold feet, thin, shiny skin, purplish skin, dry, scaly skin, or loss of hair are signs that the feet are not getting enough blood.

Diabetic neuropathy can lead to unusual sensations in the feet and legs, including pain, burning, tingling and numbness. The patient may lose the ability to recognize heat and cold. The perception of pressure on the feet is also often altered.

The neuropathy can evolve very slowly, causing the foot to gradually lose its sensitivity. The patient may only notice the problem when the foot is already totally unresponsive. This can be very dangerous because the patient may not be aware that the shoes are hurting, may not notice the presence of a small stone inside the shoes or notice that there is a worsening foot injury.

The structure and appearance of the feet may indicate the presence of the diabetic foot. The nerve injury can change the way the patient steps and rests on the feet, causing joint and bone deformities.

Any sores or redness on the feet of a diabetic patient should be carefully examined. Diabetic foot ulcers usually start with small wounds, which in other people would heal without problems.

Diabetic foot ulcers

Diabetic foot ulcers usually arise for two reasons: wounds caused by trauma or unsuitable shoes; or chronic ulcers, usually in the soles of the feet, caused by the combination of diabetic neuropathy, poor circulation and bone deformities.

Because the diabetic patient usually has low immunity and poor circulation in the feet, these ulcers, in addition to not easily heal, are still at risk of becoming contaminated with bacteria that naturally colonize the skin, such as streptococci and staphylococci.

Ulcers, if not treated properly, can progress to extensive and deep lesions, even compromising muscles and even bones. An infected ulcer may evolve with osteomyelitis, which is a serious infection of the bones. In some cases, when blood circulation is already severely compromised, antibiotics do not work to treat the infection and the only solution is amputation of the foot to prevent the patient from dying of widespread infection.

General keywords

User discussion

Site indexMedicines onlineInteresting to readCommentaries
TabletsManual.com © 2012