Diabetic foot: What are its causes and symptoms? How can it be prevented?

According to the WHO, diabetes (type 1 and type 2) is the world's leading non-infectuous disease. In the UK, more than 4.9 million people are affected.

Complications and comorbidities linked to this disease are numerous; it increases the risk of cardiovascular disease, blindness and severe infections, and the treatments are very limiting.

Poorly controlled diabetes affects the blood flow and sensitivity of the feet.

One of the complications, which affects about 20% of diabetic patients, is foot damage, which results from peripheral neuropathy. This complication is very serious, as it can lead to amputation.

What are the symptoms of diabetes-related foot problems? 

One of the main symptoms of foot damage is insensitivity to pain, but also to heat and cold. This complication results from neuropathy, which is a functional and structural alteration of the nerves.

Neuropathy leads to reduced sensitivity of the contact nerves and disrupts sensitivity to pain. The patient may be very sensitive to pain or, on the contrary, may not know there is a wound or an abnormality on his or her feet, such as a corns and calluses, a crack, a crevice or a fungal infection.

These small wounds, often caused by lack of hydration, can become infected and spread, which can lead to an increased risk of amputation. This can also be a plantar perforating disease, a specific complication of neuropathy.

Neuropathy also leads to unnoticeable foot pain, tingling and pins and needles, difficult healing and foot deformities of varying degrees, such as hallux valgus, curled toes or claw toes. These deformities provoke rubbing and thickening of the skin.

Another cause of diabetic foot damage is arteriopathy, which leads to arteritis, a decrease in the diameter of the arteries, in this case of the lower limbs, which occurs gradually. Hyperglycaemia linked to diabetes weakens the artery walls, favours the deposit of cholesterol and contributes to the development of atheromatous plaques. Arterial disease leads to poor wound healing and risk of infection; arteries can become blocked, which results in reduced oxygen supply to the feet. The symptoms of arterial disease are: cramps in the calves that appear after walking or physical exercise, and disappear when the person is resting, cold and pale feet, and ulcers.

How to treat diabetes-related foot problems? 

It is important to inspect your feet regularly and, if you have a wound, clean it thoroughly with soap and water before drying it and disinfecting it with an antiseptic (an antiseptic should always be rinsed off after use because of its cellular toxicity and the delay in healing it can cause), then cover it with a tulle dressing.

If the wound becomes deep, surgery may be necessary, otherwise the wound may degenerate and lead to necrosis which in its turn may lead to amputation. Antibiotic therapy may be necessary, and being seen by a specialist will increase the chances of recovery.

Next, the triggering factor for the wound should be identified and removed. It may be a foreign body, unsuitable footwear, extremely long nails, walking barefoot, etc.

It is also recommended to see a podiatrist who will carry out podobarometric assessment in order to analyse the pressure under the arch of the foot. The podiatrist can prescribe insoles to reduce the pressure on certain areas of the foot, or orthopaedic shoes.

In the case of diabetic arteritis, the doctor may prescribe antiplatelet agents (Clopidogrel®) to thin the blood, and statins (Atorvastatin®, Simvastatin®) to lower the level of cholesterol in the blood.

How to prevent diabetes-related foot problems? 

It is recommended that diabetic patients have their feet checked at least once a year. The doctor will then be able to determine the degree of severity of peripheral neuropathy: from grade 0 (absence of sensitive neuropathy) to grade 3 (history of foot wounds and/or amputation).

You may be eligible for an NHS podiatrist if you have diabetes and symptoms of foot damage. You should ask your GP for a referral.

Prevention of diabetes foot complications also involves :

• Taking good care of your feet, toes and nails,

• Controlling and monitoring the condition of your feet, e.g. by checking them regularly for injuries,
  

• Taking appropriate treatment in the case of injury or foot abnormality,
  

• Controlling your diabetes and avoiding foods/substances that affect blood circulation (e.g. tobacco) if you already suffer from foot infection,
  

• Choosing appropriate footware. It is preferable not to walk barefoot, and to wear shoes adapted to the morphology of your feet, your walking habits and the general condition of your feet,
  

• Monitoring your levels of glycated haemoglobin.
  
  

If signs of loss of sensitivity or other symptoms appear, it is essential to see your doctor. Peripheral neuropathy is strongly related to blood sugar control. Thus, a well-controlled and stabilised diabetes will improve the symptoms of neuropathy.

The podiatrist plays an important role in the prevention of diabetic foot damage. They assess the risks by carrying out tests to determine whether or not neuropathy or arteriopathy are present.

Diabetic foot damage is therefore a direct consequence of poorly controlled diabetes. When blood sugar levels have been too high for too long, it has an impact on the nervous system of the affected individual. Foot damage is therefore a serious condition that can worsen to the point of gangrene or amputation. This is why it is necessary to be able to quickly detect the symptoms and treat them as soon as possible.

It is also worth mentioning that certain lifestyle habits can increase the risk of foot damage, such as smoking, poor hygiene, excess weight or obesity, and failure to treat lesions that seem harmless.