Auckland DHB Diabetes Centre
Public Service, Endocrinology
The feet are supplied with blood to keep them healthy. They also have a multitude of nerves that act as an emergency warning system. For example, if there is a stone in the shoe, the nerves will send a message to the brain to investigate. However, if diabetes is poorly controlled for a long period of time this may lead to:
• Nerve damage, or ‘peripheral neuropathy’, which impairs sensation to the feet, and/or
• Reduced blood supply, also known as ‘poor circulation’.
Nerve damage may mean that the patient no longer notices the stone in their shoe, due to loss of sensation in their feet. This could then lead to an injury they can’t feel and possibly infection.
If there is poor circulation, any injuries or infections on the feet (i.e. cuts, burns or scratches) will take longer to heal. This is due to less blood flowing into the arteries in the foot. Blood provides energy to working muscles and aids in healing any tissue damage.
Most foot problems for people who have diabetes occur when injuries - and often infections - go unnoticed and untreated, or when healing is delayed due to poor circulation.
Ulcers are an area of skin that is broken and is taking longer than normal to heal. Often the inside of an ulcer looks white. Ulcers occur most often over the ball of the foot or on the bottom of the big toe. Ulcers on the sides of the foot are sometimes due to poorly fitting shoes.
Remember, even though some ulcers do not hurt, every ulcer should be seen by a healthcare provider right away. Not getting treatment for an ulcer can result in infection or gangrene, which in turn can lead to losing a limb (amputation).
Corns and calluses are a thickening of the skin. They are caused by repeated pressure or rubbing on the same area of the foot. Corns are often round, raised areas on the foot at points where the foot rubs against the shoe. Calluses are often larger areas of thickened yellowish skin around the heels or underneath the foot.
If not treated, corns and calluses can act like stones in the shoe, putting pressure on the tissue underneath them. This pressure can lead to bruising, infection or an ulcer.
This damage is often hard to see because it is underneath the corn or callus. If there is nerve damage the patient may not feel any pain. Show any corns or calluses to a podiatrist to get them treated. Never try to cut or cure corns yourself.
Neuropathy, excessive weight and poor footwear can lead to cracking of the skin. Cracks allow bacteria to enter the foot and can cause infection which can be serious. It is important to keep the skin on the feet soft and supple. Regularly moisturising the skin will help prevent cracks or fissures.
Problem nails can be caused by injury, fungal infection, curved nails and badly fitting shoes. An in-grown nail may be painful, red and swollen, or have a fluid discharge. It can get infected very quickly. Get any problem nails seen by a podiatrist.