April 1, 2011
Dear Mayo Clinic:
Lately my feet always seem cold but are not cold to the touch. Could this be an early symptom of something to come?
Pinpointing the exact source of this symptom requires a physical exam and diagnostic tests. But when feet feel cold but are not cold to the touch, a possible cause is a neurologic problem, such as peripheral neuropathy.
Of course, feet can get cold for many reasons. The most obvious is a cold environment, along with a lack of proper shoes or socks. Frequent or constant sweating (hyperhidrosis) can also make feet feel cold, especially when evaporation cools the feet quickly. This can often be caused by nervousness, literally "getting cold feet." Lack of adequate blood flow to the feet through the arteries can also make the feet cold. But in all these situations, the feet feel cold to the touch.
Often the sensation of cold feet is benign and there is no serious underlying cause. However, experiencing the sensation of cold feet that don't feel cold to the touch may be a sign of a nerve problem. For example, peripheral neuropathy can cause this symptom. Peripheral neuropathy occurs as a result of nerve damage caused by injury or an underlying medical disorder. Diabetes is one of the most common causes of peripheral neuropathy, but the condition may also result from vitamin deficiencies, metabolic problems, liver or kidney diseases, infections, or exposure to toxins. The condition can also be inherited. Sometimes the cause of peripheral neuropathy is never found.
The peripheral nerves are all of the nerves in the body that are outside of the brain and spinal cord (central nervous system). Peripheral neuropathy frequently begins in the body's longest nerves, which reach to the toes. So symptoms often appear in the feet first and then the lower legs. Other potential symptoms caused by peripheral neuropathy include numbness; a tingling, burning or prickling feeling in the feet and legs that may spread to the hands and arms; sharp or burning pain; and sensitivity to touch. As peripheral neuropathy progresses, loss of feeling, lack of coordination, and muscle weakness may develop.
You should see your doctor to have your situation evaluated. If your doctor suspects peripheral neuropathy or other nerve damage, a variety of tests may be used to uncover the underlying source of the problem. To help in the diagnosis, your doctor will likely talk with you about your medical history and perform a physical and neurological exam that may include checking your reflexes, muscle strength and tone, ability to feel certain sensations, and posture and coordination.
In addition, blood tests may be used to check vitamin levels, thyroid function, blood sugar levels, liver function and kidney function, as all these can affect your nerves. Your doctor also may suggest electrophysiologic testing known as electromyography (EMG) and nerve conduction studies (NCS). These tests measure the electrical signals in the peripheral nerves and how well the nerves transfer signals to your muscles.
In some cases, a nerve biopsy — a procedure in which a small portion of a sensory nerve near the ankle is removed and examined for abnormalities — and imaging tests, such as an MRI or CT scan, may also be needed to help determine the cause of nerve damage.
It's important to have your situation assessed by your doctor soon. If peripheral neuropathy is the source of the problem, and the cold sensation in your feet is the only symptom, you may be in the early stages of the disorder. In that case, finding and treating the underlying cause of the nerve damage may be all that's necessary. Nerve damage that progresses can lead to pain and other symptoms which can be more difficult to successfully treat.
— John Jones, M.D., Vascular Center, Mayo Clinic, Rochester, Minn.