Diseases of the Foot
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 develop an ulcer. This can be even after a mild injury such as stepping on a small stone in your bare feet.
People with diabetes are prone to foot ulcers because one or both of the following complications develop in some people with diabetes:
- Reduced sensation of the skin on the feet
Your nerves may not work as well as normal because even a slightly high blood sugar level can, over time, damage 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. Therefore, you are more prone to problems such as minor cuts, bruises, 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 arteries (blood vessels) going to the feet
If you have diabetes you have an increased risk of developing 'furring' of the arteries. This is caused by fatty deposits called atheroma that build up on the inside lining of 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 is prone to become worse and develop into an ulcer. In particular, if you also have reduced sensation and cannot feel the wound.