A relatively common medical problem seen in the population over age 50 is the feeling that the bottoms of their feet are numb or sometimes painful.  The problem begins slowly but eventually is described as feeling like the bottom of their feet have a coating of plastic or leather or thick paint stuck to the bottom of the feet diffusely most prominently on the toes.  Sometimes the sensation will be associated with a burning pain.  Other patients describe the pain as aching and throbbing.  While everyone gets sore feet if they walk an unusual distance, the pain considered here is not necessarily related to how far the person has walked that day.  Instead it very frequently interferes with sleep being most prominent when the person is sitting down or resting.  For most patients it involves both feet the same.  The strength of the foot muscles does not seem to be involved.

     Most patients seek medical attention wondering why their feet are numb.  Sometimes patients will come in order to achieve relief from the pain that is occurring.  Their first question is why are their feet numb?

     The medical term to describe this clinical picture is “distal symmetrical sensory neuropathy”.  The word “distal” describes the problem as occurring at the ends of the arms or legs.  “Symmetrical” means that both feet involved the same.  “Sensory” means that only the sensory nerves are involved; the nerves that run the muscles don’t seem to be involved.  The prefix “neuro” refers to the nerves being the problem and suffix “-pathy” refers to there being a disease state.  Thus, distal symmetrical sensory neuropathy means that there is something wrong with the sensory nerves in the feet.

     If a piece of skin is taken off of a person with this problem and then examined under the microscope it can be seen that there are a lot less nerve endings in the skin than there are normally.  A few serial studies have been shown that as the condition progresses, more nerves seem to degenerate from the skin surface.  Thus the reason the feet feel numb is that there are not enough nerve endings in order to create normal sensation.

     The obvious question that arises is why the nerve endings are degenerating.  Several large medical centers have reviewed their cases of this condition.  By far the most common cause is diabetes mellitus.  Adult diabetes mellitus tends to be a slow onset condition that often isn’t diagnosed until something such as the distal symmetrical sensory neuropathy occurs and the person comes for medical attention.  Sometimes the person is not truly diabetic yet but instead has what is called “impaired glucose tolerance” which means that they are on  their way to becoming diabetic but not with high blood sugars yet.  Other causes include alcohol excess, malnutrition, several familial conditions, a type of cancer called multiple myeloma, and Vitamin B-12 deficiency.  When a person comes for medical attention to their numb feet problem, tests can be done to find the cause.  About 30% of patients who have this problem will have no detectable cause.

         The next question that patients have is how do they make this problem go away.  Unfortunately, once the numb feet have occurred and the nerves have degenerated, they don’t grow back.  Further degeneration of the remaining nerves can be prevented by dealing with the basic underlying cause if it can be found but once the feet are numb that is the way that they are going to be.  If the person is diabetic, further progression of the problem can be prevented by control of the diabetes.  Blood sugars have to very tightly controlled in the low normal range in order to stop the progression of this problem.

     The danger of distal symmetrical sensory neuropathy is that the person is not able to feel harm occurring to their feet.  If they step on a tack or cut their foot or get an infection, they don’t feel it and thus unless they pay special attention to their feet on a regular basis, infections can become quite severe before they are ever detected.  This results in approximately 85,000 amputations per year for people who have diabetes with an associated neuropathy.  Thus this problem can be quite severe and because it is irreversible, it requires life long attention.

     When a person has developed distal symmetrical sensory neuropathy, it is important that the cause be found and arrested if such is possible.  Tight blood sugar control is critical.  Each day as the person puts their shoes on, they should inspect their feet for cuts or scratches or foreign bodies so that the problems are addressed early before infections become severe.   Foot protection becomes critical.  Going barefoot in the yard is a “no, no”.   Comfortable, protective, loose-fitting shoes are critical.   Pointed cowboy boots are not advised.  Open toe sandals are not advised.

     The healthcare professionals at your local clinic are well versed on this condition and can help in finding the cause, preventing further damage, and providing measures to protect your feet.  For those individuals who are having pain associated with the numbness, there are medications that can decrease the pain for about 40% of neuropathy patients.  Unfortunately, most of the medications are incompletely effective and have side effects that are not a fair trade for a relief that the medication provides.  Even so medications do help some people.