What is a foot ulcer?
A skin ulcer is where an area of skin has broken down and you can see the underlying tissue. Most skin ulcers occur on the lower legs or feet. The skin normally heals quickly if it is cut. However, in some people with diabetes the skin on the feet does not heal so well and is prone to developing an ulcer. This can be even after a mild injury such as stepping on a small stone in your bare feet.
Why are people with diabetes prone to foot ulcers?
Foot ulcers are more common if you have diabetes because one or both of the following complications develop in some people with diabetes:
Reduced sensation of the skin on your feet
Your nerves may not work as well as normal because even a slightly high blood sugar level can, over time, damage some of your nerves. This is a complication of diabetes, called peripheral neuropathy of diabetes.
The nerves that take messages of sensation and pain from the feet are commonly affected. If you lose sensation in parts of your feet, you may not know if you damage your feet. For example, if you tread on something sharp or develop a blister due to a tight shoe. This means that you are also more prone to problems such as minor cuts, bruises or blisters. Also, if you cannot feel pain so well from the foot, you do not protect these small wounds by not walking on them. Therefore, they can quickly become worse and develop into ulcers.
Narrowing of blood vessels (arteries) going to the feet
If you have diabetes you have an increased risk of developing narrowing of the arteries (peripheral arterial disease). This is caused by fatty deposits called atheroma that build up on the inside lining of arteries (sometimes called furring of the arteries). This can reduce the blood flow to various parts of the body.
The arteries in the legs are quite commonly affected. This can cause a reduced blood supply (poor circulation) to the feet. Skin with a poor blood supply does not heal as well as normal and is more likely to be damaged. Therefore, if you get a minor cut or injury, it may take longer to heal and be prone to becoming worse and developing into an ulcer. In particular, if you also have reduced sensation and cannot feel the wound.
What can I do to help prevent foot ulcers?
Have your feet regularly examined
Most people with diabetes are reviewed at least once a year by a doctor and other health professionals. Part of this review is to examine the feet to look for problems such as reduced sensation or poor circulation. If any problems are detected then more frequent feet examinations will usually be recommended.