Why Does Diabetic Foot Develop?

Diabetic foot problems commonly develop due to a combination of nerve damage, poor blood circulation, and increased susceptibility to infection.

1. Diabetic Neuropathy (Nerve Damage)

Long-term high blood sugar can damage the nerves, particularly those supplying the feet. This condition is known as diabetic peripheral neuropathy.

It may cause:

• Reduced sensation or numbness in the feet.
• Tingling, burning, or a pins-and-needles sensation.
• Loss of ability to feel pain, heat, or pressure.
• Muscle weakness and changes in foot shape.
• Increased risk of unnoticed cuts, blisters, and injuries.

When sensation is reduced, a person may continue walking on an injured area without realising it, making the wound worse.

2. Poor Blood Circulation

Diabetes increases the risk of peripheral artery disease (PAD), a condition in which arteries supplying blood to the legs and feet become narrowed or blocked.

Reduced blood flow means less oxygen and fewer nutrients reach the affected tissues. As a result:

• Wounds may heal slowly or fail to heal.
• The skin may become dry, thin, or discoloured.
• The feet may feel unusually cold.
• Pain may occur in the legs or feet, particularly while walking or at rest.
• Severe circulation problems may cause tissue damage or gangrene.

3. Infection

High blood sugar and damaged skin can make infections more difficult to control. A minor wound may become infected and spread into deeper tissues or bone if not treated promptly.

Infections may lead to:

• Redness and swelling.
• Warmth around the affected area.
• Pus or unusual discharge.
• Foul-smelling wounds.
• Fever or other signs of systemic infection.

What Are the Symptoms of Diabetic Foot?

Symptoms vary depending on the severity of nerve damage, circulation problems, and infection.

Common warning signs include:

• Numbness or loss of sensation in the feet.
• Burning, tingling, or unusual sensations.
• Dry, cracked skin.
• Blisters, cuts, or sores that do not heal.
• Swelling or redness in the foot.
• Changes in skin colour, including pale, bluish, or darkened areas.
• Thickened toenails or fungal infections.
• Corns and calluses, particularly over pressure points.
• Foot pain while walking or at rest.
• Discharge, pus, or an unpleasant smell from a wound.
• Blackened tissue or gangrene.

Important: A diabetic foot ulcer may not be painful because of nerve damage. The absence of pain does not mean the wound is harmless.

What Is a Diabetic Foot Ulcer?

A diabetic foot ulcer is an open wound or sore that develops on the foot, commonly on the sole, heel, toes, or pressure-bearing areas.

It often develops when repeated pressure, friction, or an unnoticed injury damages the skin. Reduced sensation allows the injury to go unnoticed, while poor circulation can delay healing.

Diabetic foot ulcers can be classified according to their depth and severity:

• Superficial ulcer: Involves the skin’s outer layers.
• Deeper ulcer: Extends into tissues beneath the skin, such as fat, tendons, or muscles.
• Infected ulcer: Contains infection that may spread to surrounding tissues.
• Severe ulcer: May involve bone, tissue death, or gangrene.

Early treatment is essential to prevent the wound from becoming deeper or more complicated.

How Is Diabetic Foot Diagnosed?

A healthcare professional evaluates the foot to identify nerve damage, circulation problems, infection, and the severity of any wound.

Depending on the findings, the following tests may be recommended.

1. Physical Foot Examination

The doctor examines both feet for:

• Cuts, ulcers, blisters, and calluses.
• Skin colour and temperature changes.
• Swelling, deformities, and pressure points.
• Signs of infection or tissue damage.
• Foot pulses and other signs of reduced circulation.

2. Neuropathy Assessment

Tests may include:

• Monofilament test: Checks whether the patient can feel light pressure on different areas of the foot.
• Vibration testing: Evaluates the ability to sense vibration.
• Reflex testing: Checks certain nerve reflexes.
• Temperature or pinprick testing: May help assess sensory changes.

3. Ankle-Brachial Index (ABI)

The ankle-brachial index compares blood pressure measured at the ankle with blood pressure measured in the arm. It helps identify possible peripheral artery disease.

However, in some people with diabetes, calcified and less compressible arteries can make ABI results misleading. Additional vascular tests may therefore be required.

4. Doppler Ultrasound

Doppler ultrasound evaluates blood flow through the arteries supplying the legs and feet.

It can help identify narrowed or blocked arteries and assess circulation in the affected limb.

5. Toe Pressure and Toe-Brachial Index

Toe pressure measurements and the toe-brachial index can help assess blood circulation, particularly when ankle arteries are difficult to compress.

These tests may help estimate the potential for wound healing.

6. CT Angiography (CTA) or MR Angiography (MRA)

These imaging tests provide detailed views of blood vessels and may help identify the location and extent of arterial narrowing or blockage.

They can assist doctors in planning vascular treatment.

7. Catheter Angiography

Catheter angiography is an imaging procedure in which a thin catheter is guided into the blood vessels and contrast dye is injected to visualise blood flow.

It can provide detailed information about narrowed or blocked arteries. In selected cases, treatment such as angioplasty may be performed during the same session.

8. Infection and Bone Assessment

If an infection is suspected, investigations may include:

• Blood tests to assess inflammation and infection.
• A wound sample when appropriate to identify bacteria.
• X-rays to look for bone damage or foreign material.
• MRI when deeper infection or osteomyelitis (bone infection) is suspected.

What Are the Treatment Options for Diabetic Foot?

Treatment depends on the condition of the foot, the severity of the wound, the presence of infection, and the adequacy of blood circulation.

A coordinated treatment plan may involve diabetes specialists, vascular specialists, wound-care professionals, surgeons, and podiatrists where available.

1. Blood Sugar Management

Good blood sugar control is an important part of diabetic foot treatment.

The doctor may review:

• Diabetes medications or insulin.
• Blood glucose monitoring.
• HbA1c levels.
• Diet and physical activity.
• Other conditions such as high blood pressure and high cholesterol.

Managing these factors supports overall health and helps reduce the risk of further complications.

2. Wound Care and Dressing

Appropriate wound care helps protect the affected area and supports healing.

It may include:

• Cleaning the wound using appropriate techniques.
• Removing dead or damaged tissue when clinically indicated (debridement).
• Applying suitable wound dressings.
• Managing excess moisture and wound discharge.
• Monitoring the wound for infection and healing progress.

Wound care should be guided by a trained healthcare professional. Patients should not attempt to cut away calluses or dead tissue themselves.

3. Antibiotic Treatment

Antibiotics may be prescribed when a diabetic foot wound is clinically infected.

The choice and duration depend on the severity of the infection, the likely organisms, test results, and the patient’s clinical condition.

Antibiotics are not routinely required for ulcers that show no signs of infection.

Severe infections may require hospital admission, intravenous antibiotics, and urgent surgical assessment.

4. Offloading and Pressure Relief

Reducing pressure on the affected area is essential for healing many diabetic foot ulcers.

Offloading methods may include:

• Special therapeutic footwear.
• Custom insoles.
• Removable walking boots.
• Total contact casts in suitable patients.
• Other pressure-relieving devices.

The appropriate method depends on the wound location, infection status, circulation, and the patient’s ability to use the device safely.

5. Revascularisation to Improve Blood Flow

When poor circulation prevents a diabetic foot wound from healing, restoring blood flow may be necessary.

This is known as revascularisation. It aims to improve blood supply to the affected leg or foot.

Treatment may involve minimally invasive endovascular procedures or open vascular surgery, depending on the patient’s condition and arterial anatomy.

Angioplasty for Diabetic Foot

Angioplasty is a minimally invasive procedure used to widen narrowed or blocked arteries.

During the procedure:

• The patient receives local anaesthesia, with additional sedation when appropriate.
• A small puncture is made, commonly in an artery in the groin or sometimes the foot.
• A thin catheter and guidewire are advanced through the blood vessels.
• Contrast dye and imaging help identify the narrowed or blocked artery.
• A small balloon is positioned across the affected area and inflated to widen the artery.
• In selected cases, a stent may be placed to help keep the artery open.
• Blood flow is reassessed before the procedure is completed.

The aim is to improve circulation to the foot, support wound healing, and reduce the risk of further tissue damage.

Not every patient needs a stent. The treatment approach depends on the location and nature of the blockage.

Other Endovascular Treatments

Depending on the arterial blockage and the patient’s condition, a vascular specialist may consider:

• Balloon angioplasty.
• Drug-coated balloon angioplasty in selected cases.
• Stent placement when appropriate.
• Treatment of multiple arterial blockages.

Surgical Revascularisation (Bypass Surgery)

In some patients, bypass surgery may be recommended when endovascular treatment is unsuitable or unlikely to provide adequate blood flow.

The procedure creates an alternative route for blood to reach the affected part of the leg or foot, using a suitable vein or graft.

The decision between angioplasty and bypass surgery depends on the patient’s overall health, available blood vessels, severity of disease, and expected benefits and risks.

6. Surgical Treatment and Debridement

Some diabetic foot wounds require surgical treatment.

Depending on the condition, this may involve:

• Removal of dead or infected tissue.
• Drainage of an abscess.
• Removal of infected bone in selected cases.
• Correction of structural foot problems that cause repeated pressure.
• Amputation when severe infection or irreversible tissue damage makes limb preservation impossible.

The goal is to control infection, preserve as much healthy tissue as possible, and protect the patient’s overall health.

What Are the Benefits of Diabetic Foot Angioplasty?

When suitable for the patient, angioplasty may offer several benefits:

• Improves blood flow to the affected leg and foot.
• May help a diabetic foot ulcer heal.
• May reduce pain caused by poor circulation.
• Can help preserve healthy tissue.
• May reduce the risk of major amputation in appropriately selected patients.
• Is minimally invasive compared with open bypass surgery.
• Usually requires a smaller access site and may allow a shorter recovery than open surgery.

The results vary depending on the severity of arterial disease, wound condition, infection, and the patient’s overall health.

Angioplasty cannot reverse nerve damage or directly treat an infection. Wound care, infection management, pressure relief, and diabetes control remain essential.

What Are the Risks and Complications?

Although angioplasty is generally considered a minimally invasive procedure, it has potential risks.

These may include:

• Bleeding or bruising at the catheter insertion site.
• Blood vessel injury.
• Allergic reaction to contrast dye.
• Kidney-related complications from contrast dye, particularly in patients with existing kidney problems.
• Blood clot formation.
• Re-narrowing or re-blockage of the treated artery.
• Infection.
• Rarely, damage to the limb due to reduced blood flow or other complications.

The risks vary from patient to patient. The treating specialist will explain the expected benefits and possible complications before the procedure.

How Should You Prepare for Diabetic Foot Angioplasty?

Preparation depends on the patient’s health, medications, kidney function, and the planned procedure.

The medical team may recommend:

• Reviewing medical history and existing health conditions.
• Checking blood glucose and HbA1c.
• Blood tests, including kidney function and blood clotting tests when indicated.
• Reviewing medications, including diabetes medicines, insulin, blood thinners, and antiplatelet medicines.
• Allergy assessment, especially for previous reactions to contrast dye.
• Reviewing previous Doppler ultrasound or angiography reports.
• Fasting for the period advised by the hospital if sedation or anaesthesia is planned.

Do not stop insulin, blood thinners, or other prescribed medicines without instructions from your treating doctor.

Recovery After Diabetic Foot Angioplasty

Recovery varies according to the procedure, the patient’s general health, and the severity of the underlying circulation problem.

After angioplasty:

• The catheter insertion site is monitored for bleeding or swelling.
• The patient may need to remain in bed for a period, depending on the access site and closure method.
• Blood flow and circulation in the treated limb are assessed.
• The medical team monitors blood pressure, blood glucose, and other relevant parameters.
• Prescribed medicines are continued or adjusted as advised.

Some patients can return home relatively soon, while others may need a longer hospital stay due to infection, complex wounds, or other medical conditions.

The foot wound will continue to require appropriate dressing, pressure relief, and regular assessment even after blood flow improves.

Can Diabetic Foot Be Prevented?

Many diabetic foot complications can be reduced through regular foot care and good diabetes management.

Recommended preventive measures include:

Daily Foot Inspection

• Check both feet every day, including the soles and spaces between the toes.
• Look for cuts, blisters, swelling, redness, cracks, or colour changes.
• Use a mirror or ask someone for help if you cannot see the bottom of your feet.

Proper Foot Hygiene

• Wash feet daily with lukewarm water.
• Dry carefully, especially between the toes.
• Apply moisturiser to dry skin, but avoid applying it between the toes.
• Avoid soaking feet for long periods.

Safe Footwear

• Wear comfortable, properly fitting footwear.
• Avoid walking barefoot, even indoors.
• Check shoes for stones, sharp objects, or rough areas before wearing them.
• Use suitable socks and footwear to reduce friction and pressure.

Nail and Skin Care

• Trim toenails carefully and avoid cutting them too short.
• Do not cut corns or calluses yourself.
• Seek professional help for ingrown nails, thickened nails, or skin problems.

Regular Medical Check-ups

• Have your feet examined regularly by a healthcare professional.
• Attend diabetes reviews and monitor blood glucose.
• Seek early treatment for even minor foot injuries.

When Should You Seek Medical Attention?

People with diabetes should not ignore new foot problems.

Seek prompt medical assessment if you notice:

• A cut, blister, or wound that is not healing.
• New redness, swelling, or warmth.
• Pus or discharge from a wound.
• Unusual skin colour changes.
• New or worsening foot pain.
• A foot that becomes unusually cold.
• Loss of sensation or a new area of numbness.

Seek urgent medical attention if you notice blackened tissue, rapidly spreading redness or swelling, severe pain, fever, confusion, or signs of a serious infection. Do not wait for the wound to become painful, as nerve damage may reduce pain sensation.