Tingling and Numb Feet: Causes and Which Tests to Have

A doctor starts by asking exactly where it tingles and how it develops, because that narrows the list of causes before any tests. Symmetrical symptoms in both feet, growing slowly from the toes, point to polyneuropathy. One-sided symptoms in an area running along the leg (for example from the buttock through the back of the thigh to the outer edge of the foot) suggest a pinched nerve root in the lumbar spine. Pain radiating from the back is sciatica, which we cover in a knowledge base entry.

Tingling, burning or numbness of the sole, worse after standing and at night, can be a sign of tarsal tunnel syndrome, in which the tibial nerve is compressed behind the inner ankle bone. Pain and numbness between the toes (usually the third and fourth) in tight shoes suggests Morton's neuroma. Numbness of the top of the foot with a dropping foot when walking, especially in someone who sits with crossed legs or has recently lost weight, can result from compression of the peroneal nerve at the head of the fibula. One important point about tarsal tunnel syndrome: a 2026 systematic review (82 studies, 4,213 patients) shows there is no single diagnostic standard, and the sensitivity of provocative tests, electrophysiology and ultrasound varies widely, so the diagnosis rests mainly on symptoms and clinical examination.

Among the systemic causes, two matter most because they respond well to treatment or to halting progression. The first is a disturbance of glucose regulation. Diabetes is one of the most common causes of polyneuropathy, but nerve damage can precede the diagnosis: a meta-analysis published in the European Journal of Neurology in 2025 found a statistically significant association between prediabetes and the presence of peripheral neuropathy, measured for example by impaired vibration perception or reduced corneal nerve fibre density. The quality of the evidence is limited by heterogeneity between studies and different definitions of prediabetes, so the result is a directional signal, not an exact risk. It does suggest, though, that foot tingling in a person with 'only a raised glucose' should not be brushed off. We write more about the disease itself in the diabetes entry, and about the test that shows average glycaemia over 2 to 3 months in the HbA1c entry.

The second cause is vitamin B12 deficiency, which damages both the peripheral nerves and the spinal cord. The risk rises with a plant-based diet, long-term use of metformin or proton pump inhibitors, stomach and bowel disease and older age; abuse of nitrous oxide (laughing gas) can also deplete B12. We discuss these mechanisms in our articles on metformin and B12 and on vitamin B12 and neuropathy in people on a plant-based diet. The practical consequence: in a person with foot tingling and any of these factors, a B12 test should be among the first. How to interpret the result, including the role of methylmalonic acid and homocysteine, is explained in the vitamin B12 and homocysteine entries.

An important distinction: both conditions can coexist and mask each other. A person with diabetes on metformin has two independent reasons for neuropathy at once, and attributing all symptoms to diabetes alone can delay detection of a deficiency that is more easily reversible. Conversely, too high a dose of vitamin B6 taken for a long time can also damage nerves, so 'nerve vitamins' bought blindly are not risk-free. The dose and indications are chosen by a doctor after testing.

A clinical review in JAMA (2015) reinforces this picture: in patients without a known cause it suggests a blood count, a metabolic panel, a vitamin B12 measurement, serum protein electrophoresis with immunofixation, fasting glucose and a glucose tolerance test, and atypical features (asymmetry, non-length dependence, motor predominance over sensory, acute or subacute onset, prominent autonomic involvement) should prompt a neurology consultation. The authors also point out something less obvious: electrodiagnostic tests and magnetic resonance imaging add substantial cost, and the evidence for their routine use in typical polyneuropathy is limited.

One supplementary practical note: screening tests of the thyroid and rheumatological markers are often ordered in neuropathy, but in a single-centre study (Gallagher et al., 2013) their yield was low and they rarely changed the suspected cause or management. This does not mean TSH is pointless: hypothyroidism can cause numbness, the test is cheap, and it is often indicated for other reasons too. It means that a long list of tests 'just in case' is worth less than tests chosen to fit the symptoms.

Electromyography with nerve conduction studies (EMG/NCS) helps tell nerve damage from muscle disease, determine whether it involves the large fibres and whether it is mainly of the sheath (demyelination) or the axon, and confirm compression syndromes and radiculopathy. It is especially useful with atypical, asymmetrical or rapidly progressing symptoms. It also has a limit: it measures only the large fibres, so in small fibre neuropathy, where burning and stinging dominate, the result can be normal despite real complaints. In such cases a neurologist may order specialised tests.

Magnetic resonance imaging of the lumbar spine makes sense when symptoms suggest compression of a nerve root or the spinal canal (asymmetry, back pain, weakness of one leg, sphincter problems). Its role in typical polyneuropathy is limited, as the JAMA review notes. We describe the role of the test in the entry on magnetic resonance imaging. When vascular disease is suspected (a cool, pale foot, pain on walking, a weak pulse), the basic test is a pulse check and the ankle-brachial index, followed by Doppler ultrasound, which we describe in the entry on Doppler ultrasound of the vessels.

Tingling feet rarely call for complicated work-up, and an orderly sequence is often enough: describe the pattern, review drugs and alcohol, a few well-chosen blood tests and only then, if the picture is atypical, EMG or MRI. The good news is that the two most common reversible causes, glycaemic disturbance and B12 deficiency, can be found with simple tests. The bad news is that ignored tingling can become permanent nerve damage. If symptoms last longer than a few weeks, it makes sense to check them rather than wait.