What Is Peripheral Neuropathy, And Why Does It Start In Your Feet?

Peripheral neuropathy is the name for damage to the nerves that run outside your brain and spinal cord - the ones that reach your hands, your feet and everything in between. About 20 million people in the United States live with some form of it, and a good number of them spent years thinking it was just getting older.

Why the feet go first

Your nerves are wired a bit like an electrical system, and your feet sit at the very end of the longest wires in your body. The nerve running down to your big toe starts near the base of your spine. That is a long way for a signal to travel, and a long way for blood to carry oxygen and nutrients.

When anything interferes with that supply, the far end of the wire is the first to feel it. That is why almost nobody gets neuropathy in the shoulders first. It starts in the toes, works up the foot, and only later shows up in the fingertips - the second longest set of nerves you have.

What it actually feels like

People describe it in very different ways, and that is part of why it gets missed for so long. Some feel burning, as if their soles are too close to a heater. Some feel pins and needles that never quite go away. Others feel nothing at all, which sounds better and is not - numbness means the signal is no longer getting through.

A common early sign is the bedsheet test. If the weight of a sheet on your feet is uncomfortable at night, the nerve is firing at something that should not bother it.

Where it comes from

Diabetes is the most common cause by a distance, because high blood sugar over years damages the small vessels that feed the nerves. But it is far from the only one. Chemotherapy is another. So is a long-running shortfall of vitamin B12, a pinched or compressed nerve, heavy alcohol use, and some autoimmune conditions.

And in a large share of cases - somewhere around a third - nobody ever finds the cause at all. Doctors call this idiopathic neuropathy, which is a formal way of saying we do not know.

Why it is worth acting early

Nerves repair slowly. That is the honest part nobody enjoys hearing, and it is also the reason waiting costs you something. A nerve that is still irritated has more to work with than one that has been quietly starving for a decade.

If your feet burn at night, if your balance is not what it was, or if you have started watching the floor when you walk, those are worth taking to a doctor rather than filing under getting older.