What is Neuropathic Itch?

In a perfect world, there’s a scratch for every itch. Or, more perfect, there’s no itch.

In the real world, there’s a heck of a lot of reasons to itch. And there are nerves in the skin that have one job: noticing all the itchy things.

Fortunately, most itchiness decreases and disappears. Sometimes, however, itch recurs. And with it, a terrible cycle of itch-scratch-itch that can escalate to severe health problems.

“Chronic itch is a debilitating condition that has largely been seen as unsolvable by clinicians,” says dermatologist Blair Jenkins, MD.

Jenkins, who has extensively studied peripheral sensory neurons—nerve cells that respond to stimuli outside the body—is an expert in the skin, the nervous system, and their relationship.

Until recently, she says, chronic itch, an enduring, heightened sensitivity to external stimuli (AKA itch neurons working overtime), had no specific targeted treatments.

Understanding how the nervous system functions helps dermatologists and other healthcare professionals identify treatments for a variety of conditions, including neuropathic itch.

Dr. Jenkins is one of the few people researching neuropathic itch and how to manage it. We asked her everything we could think of about itch. Let us know if you think of any other itching questions.

What is itch?

Itch is an important sensation that helps us know when we have insects on our skin’s surface or when we’ve encountered something that might trigger a severe allergic reaction.

What is chronic itch?

Chronic itch is itch that lasts longer than six weeks. We do not know of a physiologic “purpose” for chronic itch. We consider it a hallmark of dysfunction in the nervous system. 

What is neuropathic itch?

When chronic itch is caused by direct damage to itch-sensing nerves in the body, it’s neuropathic itch.

What is NOT neuropathic itch?

Chronic itch that’s primarily caused by inflammation in the skin—chronic hives, atopic dermatitis, autoimmune blistering disorders, some genetic conditions—is not neuropathic itch.

Certain medical conditions can also cause itching through poorly understood mechanisms, such as chronic kidney or liver disease.  

The caveat here is that there is likely a neuropathic component underlying most types of itch since chronic aberrant signaling likely causes direct damage to nerves over time.

What causes neuropathic itch?

Neuropathic itch is caused by direct damage to itch-sensing nerves. 

There are many nerves that detect sensations in the skin. Some are tuned to sense pain, while others optimally sense touch. Recent evidence suggests there are specialized nerves for sensing itch. These nerves receive signals from as far out on our skin as our fingers and toes to the spinal cord and have processes that travel through tiny holes in the spine.

Sometimes, these nerves can get pinched by the spine in patients who have chronic arthritis or degenerative disk disease. Other times, these nerves can become so inflamed, such as after a shingles flare, that they are damaged and send excessive itch signals to the brain. These trigger neuropathic itch.

What does neuropathic itch feel like?

Most people describe chronic itch as a different sensation from pain, but neuropathic itch can have a stinging or burning quality. 

Often, neuropathic itch is localized to a specific limb or a focal area on the trunk or face.

Are pain and itching the same thing?

Probably not. There are conflicting theories in the scientific community about whether pain and itch are mediated by the same pathways.

Some scientists have speculated that itch is just a low-level version of pain or is caused by irritation of pain-sensing neurons. 

Others propose that itch has its own pathway in the nervous system that is completely distinct from pain. This theory is supported by the fact that therapies for pain (NSAIDs, aspirin, acupuncture) are not effective in treating chronic itch.

However, gabapentin, which helps treat chronic pain, may help treat itch. 

Currently, the prevailing itch-pain theory is that itch is mediated by its own distinct pathway in the nervous system. Translation: Pain and itch are not the same thing.

Does neuropathic itch go away?

Yes. Neuropathic itch can go away but typically only with consistent use of topical and oral medications. 

Notalgia paresthetica is a neuropathic itch condition caused by pinching of nerves typified by an area of itching on the back just lateral to the spine. People with this condition can benefit from strength training and stretching, which may help to realign the spine and alleviate itch. 

Additionally, some topical therapies, such as capsaicin, may cause permanent damage to nerve fibers. Topical capsaicin can be painful to use but may lead to long-term improvement in itch symptoms with consistent use.

Gabapentin and amitriptyline have shown some benefits. Difelikefalin is a newer medication that was recently shown to treat notalgia paresthetica in phase 2 clinical trials.

Can you treat neuropathic itch at home?

Yes, temporarily.

One of the best home remedies for itch in general is the application of cold. Cold decreases nerve excitability and may activate cold-sensing nerves in the skin, which then may “trick” the nervous system into feeling less itch. 

Cold compresses and over-the-counter menthol-containing salves can be incredibly helpful for alleviating itch in the short term.