Causes of Diabetic Foot Ulcers

Diabetic foot ulcers are one of the most common and serious complications of diabetes, especially in people with long-standing or poorly controlled blood sugar levels. These open sores usually appear on the bottom of the feet and, if not treated early, can lead to severe infections, hospitalization, and even amputation.

But what causes diabetic foot ulcers in the first place? These ulcers don’t happen overnight; they are often the result of a combination of physical, biological, and lifestyle factors. Understanding these causes can help patients take preventive steps and seek timely treatment before things worsen.

Causes of Diabetic Foot Ulcers

1. Peripheral Neuropathy (Nerve Damage)

   One of the most common causes of diabetic foot ulcers is nerve damage caused by chronically high blood sugar levels a condition called peripheral neuropathy. This reduces sensation in the feet, meaning patients may not feel pain, heat, or injury. A cut, blister, or even a tight shoe may go unnoticed and become a serious wound over time.

   When nerves don’t work properly

   • Minor injuries go undetected
     
   • Pressure on certain areas isn’t felt
     
   • Healing signals from the nervous system are disrupted
     

   This lack of protective feeling allows small injuries to turn into deep ulcers.

2. Poor Blood Circulation (Peripheral Arterial Disease)

   Diabetes often leads to narrowing or hardening of blood vessels, especially in the legs and feet. This is known as peripheral arterial disease (PAD). Reduced blood flow means less oxygen and fewer nutrients reach the feet, which

   • Slows down wound healing
     
   • Increases the risk of tissue death
     
   • Makes infections more difficult to fight
     

   Poor circulation alone doesn’t cause ulcers but makes any wound much harder to heal creating an environment where ulcers thrive.

3. Foot Deformities and Abnormal Pressure Points

   Foot deformities like hammertoes, claw toes, bunions, or Charcot foot are common in diabetic patients due to long-term nerve and muscle damage. These deformities cause uneven pressure on the sole of the foot, especially during walking or standing.

   Over time, pressure builds up under specific points (such as the ball of the foot or heel), leading to:

   • Callus formation
     
   • Skin breakdown
     
   • Deep tissue injury
     

   If left unchecked, these areas develop into open ulcers especially if the patient can’t feel the warning signs due to neuropathy.

4. Improper Footwear

   Wearing ill-fitting shoes is a major risk factor for diabetic foot ulcers. Tight shoes, high heels, pointed toes, or shoes with hard seams can rub against the skin and create blisters or pressure sores.

   In people with diabetes, this becomes more dangerous because

   • Foot shape may have changed due to nerve/muscle damage
     
   • Patients may not feel discomfort
     
   • Foot wounds are slow to heal
     

   Custom diabetic footwear or shoes with extra depth and soft insoles can help prevent such injuries.

5. Poor Foot Hygiene and Skin Care

   Neglecting basic foot hygiene increases the risk of ulcers. Without daily inspection and care

   • Small cuts, cracks, or blisters may go unnoticed
     
   • Fungal infections or dry skin may lead to skin breakdown
     
   • Dirt and sweat buildup can cause irritation or infection
     

   Daily washing, moisturizing, nail trimming, and checking for wounds is essential for foot health in diabetics.

6. Previous History of Ulcers or Amputation

   Patients who have had a foot ulcer in the past are at high risk of recurrence, especially if the underlying causes weren’t corrected. Scarred areas or previous amputation sites are structurally weaker and more prone to pressure and injury.

   According to research, up to 40% of diabetic foot ulcers reappear within a year, and about 65% within five years if preventive measures aren’t taken.

7. Infections

   Sometimes, a small wound becomes infected due to bacteria, which worsens the ulcer. In diabetic patients, the immune system is often compromised, allowing infections to spread quickly. Infected ulcers are more likely to involve deeper tissues, muscles, or even bones (osteomyelitis).

   Poor infection control can delay healing and may eventually lead to hospitalization or surgical intervention.

8. Uncontrolled Blood Sugar Levels

   High blood glucose affects

   • Wound healing by impairing immune cell function
     
   • Circulation, leading to narrowed arteries
     
   • Nerve function, worsening neuropathy
     

   Without good diabetes management, even minor injuries can evolve into severe foot ulcers. Maintaining stable blood sugar levels is the foundation of foot ulcer prevention and healing.

9. Smoking

   Smoking is a lesser-known but powerful risk factor. It

   • Reduces blood flow to extremities
     
   • Damages arteries (worsening PAD)
     
   • Impairs wound healing
     

   For diabetic patients, quitting smoking is not just about general health it’s a critical step toward preventing foot ulcers and amputations.

Conclusion

Diabetic foot ulcers are caused by a combination of nerve damage, poor circulation, deformities, improper footwear, infections, and poor diabetes management. They often start small and painless but can quickly become serious if ignored.

The good news? Most diabetic foot ulcers are preventable. With daily foot care, regular check-ups, blood sugar control, and protective footwear, patients can reduce their risk dramatically. Understanding the causes is the first step toward prevention and early action.

If you notice redness, swelling, or a sore on your foot that isn’t healing, don’t wait. Consult a foot specialist immediately early treatment can save your limb and your life.