Burning feet and numb hands: nerve damage in diabetes
Tingling, burning or numbness in the feet is not a minor complaint of old age. In diabetes it is a signal, and the feet need checking for a reason.
It usually starts quietly. A tingling in the toes at night. Feet that burn under the blanket. A patch that feels slightly distant, as though there is a sock on when there is not. Most people mention it, if at all, as an aside.
What it is
Sustained high blood sugar damages the smallest nerves first, and the smallest nerves are furthest from the spine — which is why this begins in the toes and moves slowly upward, symmetrically, on both sides.
A near-identical picture comes from vitamin B12 deficiency, which is common in people who have taken metformin for years. The two can coexist. Both are worth establishing rather than assuming, because one of them is straightforwardly correctable.
Why numb feet are the dangerous ones
Pain is unpleasant and useful. Numbness is comfortable and dangerous. A foot that cannot feel will not report the blister from a new shoe, the stone that has been there all afternoon, or the small cut from a nail.
In someone with reduced circulation and high sugar, a small unnoticed injury is how a serious ulcer begins. This is the single reason feet get examined at every diabetes review — and the reason to look at your own, daily, including between the toes and underneath.
What an assessment covers
- How long the symptoms have been present, and whether they are worse at night
- Whether both sides are affected equally, or one more than the other
- HbA1c, and how long the sugar has been running high
- Vitamin B12 and vitamin D levels
- How long metformin has been taken
- A look at the feet — skin, nails, sensation, and any area that has hardened
A foot wound that is not healing, an area that is red, hot or swollen, or any black tissue needs to be seen the same day. Do not wait, and do not treat it at home.
Questions people ask
- What causes burning or numb feet in diabetes?
- Prolonged high blood sugar damages the small nerves, typically beginning in the feet and moving upward — diabetic peripheral neuropathy. Vitamin B12 deficiency produces a similar picture and is common in people taking metformin long term, which is why it is worth checking rather than assuming.
- Why does numbness matter if it does not hurt?
- Because numbness removes the warning system. A blister, a stone in a shoe or a small cut goes unnoticed, and in someone with reduced circulation and raised sugar a minor injury can become a serious ulcer. Numb feet need looking at daily, since they can no longer tell you themselves.
- Can nerve damage be reversed?
- Early nerve symptoms often improve when blood sugar control improves and any B12 deficiency is corrected. Long-established damage is harder to reverse, though pain can frequently be reduced. This is why early symptoms deserve attention rather than tolerance.