What is notalgia paresthetica?

Notalgia paresthetica is a condition related to the nerves, also known as a sensory neuropathy¹, that causes a severe itch or burning sensation on the back between the shoulder blades and spine. It is a type of dysaesthesia that results in an uncomfortable tingling feeling, numbness or tenderness.² 

People affected by notalgia paresthetica constantly rub and scratch their skin, causing a coloured patch on their back. The name of the condition directly relates to the key symptom   ‘notalgia’, which means pain in the back, and ‘paresthetica’ means a burning itch.³ 

Notalgia paresthetica typically affects more adults assigned female at birth (AFAB), particularly those over 50 years of age. It is a type of chronic pruritus, which is a constant itching that can last for several weeks to years and affects over 20% of people. Chronic pruritus is a common symptom across different neurological conditions, such as multiple sclerosis, as well as other conditions, like skin allergies, kidney disease, diabetes, mental health conditions, and even infections, such as hepatitis and HIV.^1,2  

This article will explore the clinical tests and evaluations that are used to check for notalgia paresthetica so that symptoms can be treated effectively.

Why is an accurate diagnosis important?

Although notalgia paresthetica is not typically a health risk, it is a chronic condition that affects the nervous system rather than a skin issue. It is an often under-recognised condition due to the overlapping symptoms it presents, particularly pruritus. Notalgia paresthetica accounts for approximately 8% of all cases of chronic pruritus, indicating it is a relatively common condition.¹

It is caused by damage or irritation to certain nerves that result from nerves being compressed, pinched or injured, although the exact cause can be unclear. This means that the brain can misinterpret nerve signals and cause a painful sensation or a desire to scratch an itch that might not be present.²  

As the condition often causes long-term nerve pain, which can significantly reduce the quality of life, it is important to see your GP as soon as you experience key symptoms so that these can be investigated and diagnosed early. 

Clinical evaluation

Diagnosing notalgia paresthetica can be challenging as there is no specific test or scan that can definitively confirm or rule out the condition. Doctors use a combination of strategies to make an accurate diagnosis, including taking the patient’s history to better understand the symptoms experienced and performing physical examinations to check the affected area.²

Patient history 

A detailed description of the symptoms experienced is recorded and assessed, such as how they started, how long they have occurred, and if they have changed or worsened over time. It also involves checking if there are any triggers - these are commonly prolonged sitting, poor posture, certain clothing, especially if they are tight-fitting or restrictive, and environmental factors like a change in temperature, especially hot weather or high humidity.^1,2 

The main symptoms of notalgia paresthetica are:^2,3 

• Chronic pruritus - itchy skin is a key symptom that is constantly present, especially on the mid to upper back, usually between the shoulder blades
• Burning, tingling, tender, or numb feelings - this can be a pins and needles sensation, or feeling excessively hot or cold in the affected area
• Changes to the skin - scratch marks, redness, or visible inflammation, and changes from long-term constant scratching, such as darker or coloured skin

Physical examination

Doctors often perform a complete, detailed physical examination to check the location of the affected area on your back and if it feels sensitive or numb. They will check for any changes in the skin caused by long-term scratching or rubbing, specifically if the skin has thickened or changed colour by becoming darker, known as ‘hyperpigmentation’, or lighter, known as ‘hypopigmentation’.^2,3 

A simple movement test called Apley’s scratch test can also help to diagnose notalgia paresthetica. This test checks your shoulder movements and is performed because the constant itching typically shows up on the lower part of the shoulder blade opposite your dominant hand. It also checks how well you can reach behind your back to touch the bottom part of the opposite shoulder with your dominant hand.²

Testing for notalgia paresthetica

In most cases, notalgia paresthetica is usually diagnosed without the need for specialised tests, and further testing is only performed to confirm the diagnosis. These tests are used to check for an underlying neurological cause that can explain the symptoms presented.² 

Skin tests

An allergy skin test may be performed to check for any localised skin itch or rash that can be explained by an allergic reaction to a substance rather than a nerve-related itch. In some cases, a small sample of skin called a biopsy may be taken to rule out any other skin conditions, especially if the diagnosis is unclear. This sample is sent to the laboratory to check for signs of inflammation related to long-term itching and hyperpigmentation.² 

Imaging scans 

Doctors may want to evaluate and confirm whether the symptoms of notalgia paresthetica, especially numbness and painful itching, can be due to irritated or pinched nerves in the spine. An X-ray or MRI scan can be used to assess bone structure and the nerve branches in the upper and middle back, specifically located between T2 and T6 in the thoracic spine. This is often reported to be the affected area in people living with notalgia paresthetica due to the sharp angle that these nerves sit at when they pass through spinal muscle, increasing their risk of injury.³  

Neurological tests

A nerve conduction test may be used to check deeper for nerve damage by measuring how quickly nerve signals pass after they are stimulated on the skin. This often involves an electromyography, which checks the response of muscles after they have been stimulated to contract. These tests can confirm if nerves are compressed or trapped over a long time, but they are rarely used and are typically only carried out by neurologists.^2,3

What if it’s not notalgia paresthetica?

Although notalgia paresthetica presents with a specific set of symptoms, notably itchy skin between the shoulder blades and spine on one side of the back, the condition can be misinterpreted due to the similarities it shares with other skin and nerve conditions. It is crucial for healthcare professionals to conduct a full evaluation and thorough tests, like a skin biopsy, to confirm an accurate diagnosis and to rule out other conditions such as:^2,4

1. Macular amyloidosis - a skin condition that causes small, flat, dark-brown coloured patches on the back known as ‘macules’, caused by a buildup of a protein called amyloid. The hyperpigmentation on the skin, as well as the itchiness, numbness and painful tendency to rub the skin, can be confused with notalgia paresthetica
2. Contact dermatitis - a common skin reaction rather than a neurological condition. It is caused by an irritation to contact with certain substances like specific chemicals in detergents and soaps, or certain materials. It mainly presents with sudden itching, burning and redness, and causes painful rashes or blisters, usually at the site of contact
3. Neurodermatitis - a chronic neurological condition that causes severe itching due to overactive nerves in the skin. It usually occurs on one patch of the skin and causes a thickened layer of skin known as ‘skin plaques’, as well as darker or lighter coloured patches where the skin is scratched. However, it is not specific to the back and can occur anywhere on the body, such as the head, neck and arms
4. Tinea versicolor - a skin infection caused by a fungus that changes skin pigmentation, causing small, coloured patches usually on the back, shoulders and chest. It can feature itchy skin similar to notalgia paresthetica, but this is due to dryness and scaliness due to yeast overgrowing on the skin, rather than a neurological cause
5. Parapsoriasis - an uncommon, chronic skin condition that causes red, scaly patches on the skin, usually on the limbs. It is a persistent condition that usually presents mild symptoms such as itching, but it is difficult to clear and requires a biopsy to be diagnosed

When your GP might make a referral 

It is crucial to let your doctor know if your symptoms do not improve or seem to worsen over time so that they can initiate a referral to specialists, like dermatologists, who can investigate any skin-related concerns. You could also be referred to a neurologist who will investigate the role that your nerves can play in notalgia paresthetica, or a pain management specialist to help you manage feelings of discomfort caused by nerve pain.^2,5

Where to find support

Living with notalgia paresthetica can be challenging, but there is a wealth of support available to help you manage the condition. Joining support groups and online forums can allow you to access advice and encouragement that help you feel understood. They can also be effective for sharing lifestyle tips that can help tackle key symptoms, such as discovering specific loose clothing and materials, how to make use of cold compresses, and how to improve posture to reduce pressure on the nerves, to help you avoid excessive itching and live a comfortable life.

Summary

Notalgia paresthetica is a neurological condition that causes a chronic itch on the back and presents an uncomfortable burning, tingling or numb sensation due to nerve irritation. Diagnosis of notalgia paresthetica is formed by a detailed evaluation of the symptoms presented, physical examination of the affected area and the appropriate use of clinical tests, especially as there can be no obvious cause of the condition.

An accurate and timely diagnosis means that the correct treatment can be implemented as soon as possible, including nerve medication, topical creams, and physical therapy, which can significantly reduce symptoms and irritation. Accessing the right support and introducing lifestyle modifications can help you manage your symptoms and live a happy, comfortable life.