Dr. Roach: Red light treatments for neuropathy don’t show much benefit

Dear Dr. Roach: I have neuropathy in my left foot. It feels very hot on the bottom. My neurologist thinks it is from my sugar level, but I got my A1C down from 6.2% to 5.6% and do not have neuropathy in my right foot. A friend said that he has had some relief with red light treatment, but he experiences tingling in his feet. Does red light have an effect with burning sensations? Are there any other options to consider for relief?

— M.B.

Dear M.B.: The most classic neuropathy in people with diabetes is a symmetrical polyneuropathy, which usually affects both feet and may later affect both hands. (It’s possible you have this, and it just started on one side for some reason.) There are many other types of neuropathies, nearly all of which are more common in people with diabetes. Unfortunately, once diabetic neuropathy has started, controlling sugar levels does not make the condition go away, although it does help slow progression.

Medication for diabetic neuropathy is pretty effective at treating the pain and burning, but not as good for numbness and tingling. Red light treatment, also called monochromatic infrared energy, is provided by LEDs rather than lasers. In theory, the light can stimulate blood flow and reduce inflammation.

There have been many studies and two meta-analyses of published studies, and the results are mixed, with some studies showing benefit while others do not. Even the two different reviews came to different conclusions. What is clear is that there is a strong placebo response with this treatment. People who got a “sham” treatment (with a red light device that looked like the active device but did not provide the same type of infrared light energy) still noted improvement in symptoms. In the best-done studies, the difference between the actual red-light device and the red light bulb wasn’t significant.

Being a conservative doctor, I won’t recommend this therapy unless there is clear evidence of benefit from future studies. I will note that multiple burns have been reported, and government bodies have determined that red light treatment is not a reasonable and necessary treatment for diabetic or nondiabetic neuropathy.

Dr. Roach Writes: A recent column on electroconvulsive therapy for severe depression generated many letters (which I was expecting), all of which were favorable (which I was not expecting). Although there have been highly negative portrayals of this treatment in movies and books, many people who actually underwent the treatment, as well as their family members and caregivers, wrote me to say that their experience was “amazing.”

One of my readers also alerted me to new research at University of California San Diego, showing evidence that both electroconvulsive therapy and transcranial magnetic stimulation may work by restoring normal levels of cortical inhibition in the frontal lobes. The induced seizure activity relating to the treatment is responsible for the benefits seen through these therapies. It may be possible to achieve the same benefits with less-invasive treatments.

As a clinician who treats many patients with severe depression, having new options for therapy would be very welcome, as the medications we have are not remotely 100% effective. In addition, psychological therapy, which is also very useful but seldom a complete cure, is not available for everyone.

Readers may email questions to ToYourGoodHealth@med.cornell.edu.