There are so many causes of peripheral neuropathy, that Dr. Sabeena Malik works like Sherlock Holmes or an NCIS team to uncover the underlying condition responsible.

There is no cure for the nerve damage, but there are treatments to relieve symptoms.

“The treatment depends upon the cause. It is my job as a doctor to find the cause,” said Dr. Malik, assistant professor of general neurology at the University of Toledo. “I have to be the detective and get to the underlying disease.”

First, a patient has to be diagnosed with peripheral neuropathy, but not even that comes easily.

A research team led by Michigan Medicine with Hurley Medical Center in Flint, Mich., found that three-quarters of patients at a Flint clinic had peripheral neuropathy, and 75 percent were undiagnosed. The findings, which involved 169 people, were published in 2024.

“The amount of people with neuropathy in this study, particularly undiagnosed neuropathy, was extraordinarily high with almost three-fourths of the study population,” said study author Dr. Melissa Elafros of the University of Michigan in Ann Arbor. “This highlights the urgent need for the interventions that improve diagnosis and management of this condition, as well as the need for managing risk factors that can lead to this condition.”

Dr. Malik reports that symptoms, which range from a lack of feeling in the feet to a tingling sensation or pins and needles to outright pain, can be subjective, especially in terms of patient descriptions. In one instance, a patient described a feeling of having socks between the toes.

“An abnormal feeling can be subjective,” said Dr. Malik, noting that other descriptions include a burning or like ants crawling over the skin.

Diabetes is a common cause of peripheral neuropathy, according to Dr. Malik. It will often start in the feet, up the foreleg to the knee then moves into the hands. In this case, managing blood sugar is important to prevent nerve damage from becoming worse. This neuropathy affects as many as half of Type 2 diabetics who have had diabetes for at least 10 years.

Alcohol use disorder is a significant risk for peripheral neuropathy, Dr. Malik reports. The toxins in alcohol can destroy the sheaths that protect the nerves. Quitting or managing the drinking of alcohol is key to treatment. Again, as many as half of chronic alcohol users will develop peripheral neuropathy.

Vitamin deficiencies, particularly vitamin B1, B6, and B12, can result in peripheral neuropathy. But an excess of vitamins can do the same. In many cases, patients inflict the cause upon themselves because they followed advice from a magazine ad, Dr. Malik said. About 2 percent of the population is affected by some form of peripheral neuropathy. There is no breakdown of the number of people with vitamin deficiencies who have the condition.

Genetically inherited diseases can also result in peripheral neuropathy. Chemotherapy treatments for cancer can result in peripheral neuropathy. An overactive immune system may attack the body's nerves and result in peripheral neuropathy. Long COVID also is contributing to a growing patient population with peripheral neuropathy.

Toxins are another cause of peripheral neuropathy that can be very difficult to diagnose, according to Dr. Malik.

“Toxic neuropathies are some of the most difficult to diagnose,” she said. “During the Vietnam War era, soldiers who were exposed to Agent Orange had neuropathy.”

Another set of people experiencing peripheral neuropathy are first responders and cleanup crews after 911. The World Trade Center dust cloud is known to have spread a toxic mixture of building materials, asbestos and other pollutants. One study concluded that about 25 percent of emergency crews age 40 and older have been diagnosed with peripheral neuropathy as of 2019.

“More than one-third of people with neuropathy experience sharp, prickling or shock-like pain, which increases their rates of depression and decreases quality of life,” Dr. Elafros said. “People with neuropathy also have increased risk of earlier death, even when you take into account other conditions they may have, so identifying and treating people with or at risk for neuropathy is essential.”

However, treatment for the pain caused by peripheral neuropathy can begin before an underlying cause is determined, said Dr. Malik, noting that a lot of research is being conducted to treat and even cure the condition.

Kristy Townsend, an associate professor in the Department of Neurological Surgery at The Ohio State University, was among a group of researchers calling for a coordinated effort from the National Institutes of Health to fund neuropathy research.

“So many causes of neuropathy mean that funding is divided across institutes and this can prohibit meaningful studies assessing new mechanisms or treatments,” she said. “In general, federal research funding for neuropathy does not match its prevalence.

“Some interventions and pain therapies exist, but overall there is no cure for neuropathy currently,” she said. “Research is desperately needed to identify new options that can be developed to help patients through this complex and debilitating condition.”

First Published April 13, 2025, 4:00 a.m.