Numbness Needs Professional Evaluation

Q. I'm 84 and have tingling, burning and numbness in my lower legs. Hot water and bed covers aggravate it. I tried taking Neurontin and nortriptyline, but they both made me very sleepy. I now only take Foltx (a folate, vitamin B6 and vitamin B12 combination tablet). Although these symptoms started after a very itchy rash, the rash went away with a salve, and I was told that I have "peripheral neuropathy." (I don't have diabetes or poor circulation.) Is there any help?

A. Isabel Collins, a neurologist with subspecialty training in neuromuscular disease at the Medical College of Wisconsin, tells me that the symptoms you describe are, indeed, suggestive of a peripheral neuropathy. However, she stresses that it is not sufficient to simply know that one has a neuropathy: We need to take the next step and identify the cause of the neuropathy.

There are many causes for a neuropathy, and some causes of neuropathy are due to an underlying condition that has yet to be diagnosed. Examples include diabetes, vitamin deficiencies, infections, systemic nervous system problems, medication side effects, or rarely, an unknown cancer. Here, the neuropathy is treated by treating the underlying cause.

Some neuropathies are reversible, while others are not. In all cases, however, there are many medications that can be used to alleviate the pain, burning and tingling. You may wish to consult a neurological specialist.

Q. I'm 33 and I have had numbness in the upper outer third of my left foot for the past several months. It doesn't hurt and the numbness occurs no matter what shoes I wear. Since I have three kids under the age of 5, I'd rather not take a trip to a doctor if I can help it. Could this be serious?

A. Working from the clue that only one foot is numb, the nerve supplying feeling to that area may be "trapped" at some point in its route from the spinal cord to the foot (i.e., a pinched nerve). For example, the nerve could be compressed by a vertebral disc in the back, from trauma to the foot, leg or lower back, or after sustained or repeated external pressure to the nerve at a vulnerable site (such as when you cross your leg over your knee).

Numbness from a nerve entrapment often disappears on its own over time, once the compression is relieved. On the other hand, the numbness may be an early sign of peripheral neuropathy (see above). So, neurologist Collins agrees that, unfortunately, you need to go in for a clinical examination.

Julie L. Mitchell, MD, MS, is an Assistant Professor of Medicine at the Medical College of Wisconsin. She practices internal medicine at the Froedtert & Medical College General Internal Medicine Clinic - East. Her column appears in the Milwaukee Journal-Sentinel.