Diabetic neuropathy in the feet: when to see a nerve specialist

If you have diabetes and your feet tingle, burn or feel numb, you probably have a good idea what is behind it. Often you’re right. But not every numb or painful foot in a person with diabetes is diabetic neuropathy, and knowing the difference can change what you do next.

What diabetic neuropathy looks like

Peripheral neuropathy is usually length-dependent. The longest nerves, which reach the toes, are affected first, so symptoms typically start in the toes and creep upward, and they are usually symmetric. Diabetes is the most common cause, and diabetic neuropathy accounts for more than 50% of peripheral neuropathy in Western populations.^[1] Symptoms include numbness, tingling, aching, burning, weakness, sensitivity to touch and pain, which may be worse at night.^[2]

Some people have little pain but a significant loss of feeling. That loss of protective sensation is what puts feet at risk of ulcers and injuries you don’t feel.^[4]

How it is diagnosed

Diabetic peripheral neuropathy is primarily diagnosed clinically, through history and a neurological assessment: pinprick or temperature for small fibers, vibration for large fibers, and pressure testing with a 10 gram monofilament to assess ulcer risk. Neurology consultation and specialized testing, including nerve conduction studies and skin nerve-fiber testing, are indicated for people with atypical features, such as rapid symptom onset, severe motor impairment and asymmetrically abnormal sensation.^[2]

What protects your feet

• Look at both feet every day, with a mirror or someone’s help, for cuts, blisters, redness, swelling or nail problems.
• Wear well-fitting shoes and socks, indoors and out, and check inside shoes before you put them on.
• Test bath water with your elbow or a thermometer, not your feet.
• Don’t treat corns or calluses yourself.
• Get a comprehensive foot examination at least once a year, more often if you have loss of feeling, circulation problems or a history of ulcers.^[3]

Our sister practice explains the daily habit well in the diabetes daily foot check (external site). For any new wound or blister, don’t wait: same-day care is the rule for a foot that can’t feel.

When a nerve specialist makes sense

Diabetic neuropathy is managed mainly by your primary care physician, endocrinologist or neurologist. A foot-focused nerve evaluation complements that care in situations like these:

• Pain in one spot or one foot. A pinched nerve such as tarsal tunnel syndrome or Morton’s neuroma can occur in a person with neuropathy. Peripheral neuropathy may coexist with a compressive neuropathy and contribute to poorer results after nerve decompression, which is why the two are sorted out carefully.^[5]
• Asymmetry. Numbness that is much worse in one foot, or that follows one nerve’s territory, is one of the atypical features that call for a closer look.^[2]
• New weakness, such as toes that catch or a foot that drags. See foot drop.
• Symptoms after an injury or operation on the same foot. See nerve pain after surgery or injury.
• Symptoms that are not explained by diabetes. Low vitamin B12, alcohol and some medicines also cause neuropathy. See vitamin B12 and neuropathy.

A caution about “nerve decompression” for neuropathy

You may see surgery to release nerves in the legs promoted as a treatment for diabetic neuropathy. The American Academy of Neurology has said that, given the evidence available, this should be considered unproven, and a Cochrane review found no well-designed trials showing that it helps symmetrical diabetic neuropathy.^[6,7] That is different from releasing a specific, well-documented nerve entrapment, which is assessed individually. See peripheral neuropathy.

When to see a specialist

Make an appointment if you have new or worsening numbness, tingling or burning in your feet, if you have diabetes and haven’t had a foot examination in the past year, or if you notice changes in the shape of your feet.