Diabetic foot ulcer

People with diabetes have an increased chance of developing foot problems such as a foot ulcer. This is commonly known as 'diabetic foot'. A foot ulcer is a sore that develops on the foot, usually below the ankle.

Key points

  1. About 10 of every 100 people with diabetes (10%) will develop a foot ulcer some time during their lifetime (1).
  2. Foot ulcers occur most often on the ball of the foot or on the bottom of the big toe.
  3. Treatment of the foot ulcer will depend on the severity of the wound.
  4. Proper foot care will help prevent problems with your feet. 

Causes of diabetic foot ulcer

People with diabetes have an increased chance of developing foot ulcers because of:

Poor circulation

Diabetes causes the blood vessels of the leg and foot to harden and narrow. This impairs the blood supply to the foot, which may lead to ulceration, and healing of the wound is quite slow. Apart from diabetes, poor circulation is aggravated (made worse) by smoking, hypertension (high blood pressure) and high cholesterol.

Nerve damage

High blood glucose levels causes damage to the nerves. This results in reduced or complete loss of feeling in the foot or leg. Because of the lack of feeling or sensation, sores, cuts, bruises or any injury to the foot is often unnoticed.

Signs and symptoms of diabetic foot

Foot ulcers occur most often on the ball of the foot or on the bottom of the big toe. They may also develop on the side of the foot, usually because of poor fitting shoes. The ulcers are usually painless. Not all diabetic foot ulcers may be infected (presence of bacteria in the ulcer), but people with diabetes are at high risk of developing infection of the ulcer and the surrounding skin (cellulitis). 

Depending on the severity of the wound and the presence of infection, diabetic foot ulcer can be classified as:

  • Uninfected: the wound does not have signs of infection. 
  • Mild infection:  the area around the wound may be warm to the touch, red, slightly swollen, painful or tender, and the wound may ooze pus.  
  • Moderate infection: foot infection that involves the deeper layers of the skin, into the muscle, tendons, bone or joints.
  • Severe infection: foot infection that causes sepsis (which is a life-threatening complication of infection). The symptoms of sepsis are high body temperature (fever), fast heart beat, and heavy or quick breathing.  


If you have diabetes and notice a sore or blister on your foot, contact your doctor immediately. Neglecting ulcers can result in infection, which can cause loss of a limb. 

Treatment of the foot ulcer depends on the severity of the wound. 

  • The wound is usually cleaned with saline wash, and covered with a protective dressing.
  • If the wound is not infected, your doctor may prescribe a water-proof dressing that can be applied and left in place for up to one week.
  • If the wound shows signs of infection, your doctor may prescribe a non-sticky dressing that can be applied every one to two days.   
  • It is very important that you rest the affected foot and do not put pressure on the foot by walking on it, until the wound heals. Walking on the ulcer can worsen it by making it larger, and force infection deeper into the foot.    
  • If the foot ulcer becomes infected, your doctor will prescribe a course of antibiotics. It is very important that your take your antibiotics as they have been prescribed, and complete the course.
  • If you develop signs of a severe infection, you will be admitted to hospital. 

Also, in addition to managing the wound, attention to other lifestyle factors can also contribute to improved wound healing:

  • Maintain good blood glucose control.
  • Treat high blood pressure and high cholesterol.
  • Stop smoking. 
  • Reduce weight with exercise and healthy diet.


Proper foot care will help prevent problems with your feet. Tips for good foot care are:

  • Inspect your feet every day for blisters, cracks, sores or redness. If you have trouble reaching your feet, use a hand mirror to inspect the bottom or under side of your foot. Also inspect between your toes for signs of athletes foot
  • Use a moisturising cream for dry skin. This will prevent cracking. However, you should not apply it between the toes, as this can cause the skin to become too moist which can lead to an infection developing.
  • Do not treat calluses, or corns, or other foot problems by yourself. In particular, do not use chemicals or acid plasters to remove corns. They should be treated by a health professional such as a podiatrist.
  • Avoid being barefoot. To prevent injury to your feet, don't go barefoot, even around the house.
  • Buy proper fitting shoes. that have broad fronts with plenty of room for the toes, and have low heels to avoid pressure on the toes.
  • Plan regular foot checkups  with your doctor or podiatrist, so that your feet can be inspected for early signs of nerve damage, poor circulation or other foot problems. Schedule foot exams at least once a year or more often if recommended by your doctor.


If the foot ulcer does not heal, becomes worse, or badly infected or if the infection spreads to nearby bones or joints, then the only solution may be to surgically remove (amputate) the affected part.

Learn more

The following links provide further information on diabetic foot ulcer. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.

Diabetic foot ulcers DermNet NZ
Diabetes, Foot Care and Foot Ulcers Patient Info, UK


  1. Diabetic foot problems: prevention and management NICE guideline 26 August 2015.
  2. IWGDF Guidance on the diagnosis and management of foot infections in persons with diabetes International Working Group on the Diabetic Foot (IWGDF) 2015
  3. International Best Practice Guidelines: Wound Management in Diabetic Foot Ulcers Wounds International, 2013. 
Credits: Health Navigator Editorial Team.