Dark callus in a diabetic patient leads to amputation

I was consulted on a diabetic patient in the hospital last week who was admitted because of a foot infection. They did not know how or why the foot infection came about, only that there was a dark callus on the bottom of their foot for at least a month. They didn’t think anything of it until the foot became red and swollen, then within 24 hours there was significant drainage from the callus, redness that streaked up the leg, fever and flu-like symptoms. They also noticed their sugars running very high. This is what brought them to the emergency room. And it was this draining callus that caused me to amputate part of this patient’s foot the very next day. What was this dark callus and why did it have to end up with losing part of the foot?

With diabetes comes the loss of sensation called neuropathy. And with this comes the inability to feel increased pressure on the bottom of the foot. With this increased pressure to prominent areas, like the ones found under the big toe joint, comes callus formation. If the callus turns dark, that means there is enough pressure to the area to cause bleeding under the skin. This bleeding is what causes the callus to be dark. Any callus that goes unchecked in a diabetic patient with neuropathy can become soft underneath allowing the skin to breakdown and form an open hole called an ulcer. This can become infected, thus leading to possible amputation.

Let’s go back to the patient in the hospital. When I asked how long the callus had been there, the reply was uncertain, “maybe a month”. Daily foot inspection is the number one thing you can do as a diabetic, neuropathy or not, to save your feet. If this callus had been evaluated as soon as it was discovered, he would not have lost part of his foot.

When asked about their last podiatric foot check, the patient responded that they had never seen a podiatrist before, their regular doctor checks their feet every 3-6 months. The next step to saving your feet is to see a podiatrist on a regular basis. Although it is very important to see your primary care physician or endocrinologist (diabetic specialist) to keep your diabetes in control, it is equally important to see a podiatrist. The best thing you can do for your feet is be educated on how to save them. When I explained why I had to amputate part of the foot and how it all came about, the patient said, “If I had only known about that stuff, I would have seen you sooner”.

So why did I have to cut off part of this man’s foot? Once the soft skin under the callus starts to break down, it can become a liquid like goo of bacteria the becomes infected. With a very small opening or crack in the skin, more bacteria can enter thus setting the stage for a really bad infection. The problem is there is no where for this drainage to escape so it starts to eat away at the tissues next to it, working its way to the bone. Once the bone is full of bacteria, the best way to save the foot and usually the entire leg, is to remove the infected bone so it can no longer harbor bacteria. IV antibiotics will reduce the bacteria swimming in your blood stream from the infected foot and hopefully prevent even more bad things from happening.

Once he heals the surgery site, he will be able to walk like a normal person with a special insert inside his shoe. And now he is better educated and understands how important it is to check his feet every day and see me on a regular basis. If he sees anything that looks like a callus, he knows to call me right away. Very simple, but very important.