Tingling and numbness are nerves sending the wrong signals.
Nerves carry touch, pain and temperature from the skin to the brain. When they are damaged, they can fire false signals, felt as tingling, pins and needles or burning, or stop carrying signals at all, so the skin goes numb. The longest nerves suffer first, which is why it usually starts in the feet.
In plain words.
The most common cause is diabetes: years of high sugar damage the small nerves and their blood supply. Low vitamin B12 is the next big cause in India, especially in vegetarians and people on metformin. Others include heavy alcohol use, an underactive thyroid, kidney disease, some medicines (including some TB and cancer medicines), and leprosy, which causes numb, pale patches of skin.
Damage from diabetes or B12 usually starts in both feet and creeps up the legs, later reaching the hands: the stocking and glove pattern. Tingling in only part of the body often has a different cause, such as a pinched nerve in the wrist (carpal tunnel, with tingling in the thumb and fingers, often at night) or in the back or neck (pain shooting down a leg or an arm).
Treating the cause matters most. Keeping sugar in range slows diabetic nerve damage, and B12, given early, can let nerves recover. Nerve pain responds poorly to ordinary painkillers; nerve-pain medicines such as pregabalin, gabapentin, duloxetine or amitriptyline can ease it, started at a low dose.
Numb feet are the real danger. A stone in the shoe, a burn from hot water or a small cut can go unnoticed, get infected and turn into an ulcer. Looking at your feet every day prevents most of these.
A nerve that misfires
A long nerve runs from the sole of the foot to the spinal cord and brain. A fatty coating wraps it, so a touch on the sole sends a clear, fast signal.
High sugar or low B12 wears the coating away and frays the nerve ends. The nerve fires false signals on its own: tingling, pins and needles or burning, in the feet first, later the hands.
As more nerve endings are lost, the feet go numb. A cut, blister or stone in the shoe sends no signal and goes unfelt, so checking the feet every day matters.
Go to hospital now if
- Sudden numbness or weakness of the face, arm or leg, especially on one side, slurred speech or sudden loss of vision: call 112. It may be a stroke; note the time it started.
- Weakness in both legs that spreads upwards over hours or days: go to hospital now. If it comes with trouble breathing or swallowing: call 112.
- Numbness around the back passage or genitals, new trouble passing urine or controlling the bowels, or new weakness in the legs, with back pain: go to hospital now.
- A leg or foot that suddenly turns cold, pale or blue, painful and numb: call 112.
- A foot sore with spreading redness, swelling, pus, a bad smell, fever, or skin turning black: go to hospital now, especially if you have diabetes.
Call 112 or go to the nearest emergency department. Ambulance: 108 (102 in some states).
See a doctor within a few days if
- Numbness or tingling is new, spreading, or affects your walking or grip
- You have diabetes and find any cut, blister or sore on the foot that is not healing
- You have diabetes and a foot becomes hot, red or swollen, even without a wound or pain: see a doctor the same day
- You have numb, pale or reddish patches of skin
- Tingling comes with tiredness, pale skin or a sore tongue, which can mean low B12
Tests that help.
Not everyone needs every test. He decides which ones are worth doing for you.
| Test | What it tells |
|---|---|
| Fasting sugar and HbA1c | Diabetes, or even prediabetes, is the most common cause. |
| Vitamin B12 | Low B12 is common and treatable. A borderline result may need a further test. |
| Thyroid (TSH), kidney and liver function, blood count | Look for other common causes, and for anaemia that often comes with low B12. |
| Foot check | A doctor tests feeling with a thin nylon thread (monofilament) and a tuning fork, and looks at pulses, skin and nails. |
| Nerve conduction study | Sometimes, to measure how well the nerves carry signals, and to find a pinched nerve. |
| MRI of the spine | Only when a pinched nerve in the back or neck is suspected. |
Have it ready.
Tick them off as you gather them. The ticks stay on this phone only.
Online, or in person?
Nerve-pain medicines can cause drowsiness and dizziness: do not drive until you know how they affect you, and do not stop pregabalin or gabapentin suddenly. Taking B12 tablets on your own before the blood test can hide the result, so test first.
A video call can
- Work out the likely cause from the pattern and your reports
- Arrange the right blood tests and go through them with you
- Plan treatment of the cause, and nerve-pain medicines at a safe dose
- Teach daily foot care, and review photos of any sore
Needs a visit in person
- A hands-on foot check with a monofilament and tuning fork
- Nerve conduction studies and MRI
- Dressing and treatment of a foot ulcer
- Any sign in the red box: that is an emergency
Talk it through with Dr. Arya.
Bring your reports and medicines to a video consultation. He goes through them with you, in plain words, and says clearly if you need to be seen in person.
Book a video consultationDr. Prabhat Arya · MBBS, MD (Internal Medicine) · Delhi Medical Council Reg. No. DMC-83759