Diabetes and Your Feet

By Dr. Mark Henson, DPM

Everyone has heard of or knows someone that has lost all or part of their feet or legs to diabetes somehow. Well I’d like to break it down for you a little to make it easier to understand.

There are several different ways diabetes affects your feet, including (but not limited to) lacking normal feeling in your feet (neuropathy, see next paragraph), pre-ulcerative calluses, which are the number one cause of diabetic ulcers, and decreased blood flow to the feet, which can lead to gangrene.

Neuropathy (neu-rop-a-thy) occurs when you lose the feeling in your feet. The inability to tell if something is hot or cold, sharp or dull, etc. It doesn’t happen to everyone with diabetes however. People will sometimes experience feelings such as my feet are burning up, or ice cold both when they are normal temperature when someone else touches them. They may feel like feet are being electrically shocked or stinging when in reality they are not doing either. It’s a false signal your nerves are sending to your brain which makes you say it is happening. Again, it doesn’t happen to everyone.

The important thing to worry about with neuropathy is that if you do have diminished sensation, you must be extra careful of where you put your feet:

If you plan to soak your feet, don’t trust your feet to tell you how hot the water is; use your elbow!
Don’t walk on hot pavement in the summer barefoot as this can cause horrible burns on feet which are very difficult to heal.
Don’t cut your own toenails! Let me, or another podiatrist take care of that. You may cut yourself and not realize it, which can lead to sores which are again, difficult to heal.
In general it’s a good idea to always wear shoes. If something is dropped on the floor and broken, guess who’s the most likely to step on it– The diabetic without shoes of course!

Calluses on the bottom of the feet are by far the number one reason people develop sores, also called diabetic ulcers on people with diabetes. What happens is the feet begin to develop areas of higher pressure. The repetition of walking on these areas of higher pressure causes the body to respond by building up thicker skin over these areas so the bones that are causing this higher pressure don’t push through the skin. It’s the same as swinging an ax all day cutting wood: calluses develop on the hands. If the thick skin is allowed to get too thick, it puts too much pressure on the young, new, constantly dividing cells at the bottom of the callus. This excess pressure results in the tissue starting to break down and it begins to bleed under the callus. A sore is beginning and the only indication will be small black spots seen in the callus. The black spots are blood; it’s bleeding! If unchecked, the bleeding continues and eventually the callus is completely separated and will fall off in the socks or in the bed at night. At that point it’s a full fledged sore or diabetic ulcer.

Sores or diabetic ulcers are very difficult to heal on the bottom of the foot. This is because walking or standing causes a shearing affect on the skin which prevents the skin from sliding over from the sides and covering the wound. The gold standard for healing a diabetic ulcer is strict non weight bearing. Well, how do you get to the bathroom without walking, hopping, or crawling? Most people continue to walk on the sores. In some cases the sores get infected which sometimes leads to the unfortunate horror stories we’ve all heard.

Calluses are the reason for diabetic shoes. Diabetic shoes are good shoes, but the key is the insert inside the shoes. They are made of special materials that just by wearing them everyday they begin to equalize the plantar pressures and eliminate or significantly decrease callus formation.

Another way diabetes can affect the feet is if the arteries become narrowed or blocked on the way down to the feet. Without blood, the body starts to wall off parts of the body it can’t get blood to; this is called dry gangrene. It’s a good idea to have your circulation checked at least once a year to make sure the “pipes are open,” to your feet. This is quick and easy and can be done in our office.