What is Notalgia Paresthetica?
Notalgia paresthetica is a long-term condition that leads to an itching feeling on the inner edge of the lower shoulder blade or scapula. This condition was first observed by a Russian neurologist named Michail Astwazaturow in 1934 and is generally harmless. The cause behind this condition is not entirely known. Still, it is thought to be related to irritation or damage to specific nerves located in the middle of the back, although the exact location of this damage is still uncertain.
Some believe it could be related to the way sensory nerves travel through the muscles at certain angles. Notalgia paresthetica usually affects older women, is typically on one side of the body only, and can last anywhere from several months to a few years. There are no primary skin issues associated with this condition, but because of the chronic itching, secondary changes may occur due to incessant scratching.
Identification of this condition usually involves taking a medical history and physical examination, but sometimes more detailed imaging may be required. Although treatment options are limited and often unsatisfactory, oral nerve regulators like gabapentin have been found to be the most effective therapy.
What Causes Notalgia Paresthetica?
Notalgia paresthetica is an ailment that is not completely understood yet. Most experts generally agree that it’s a nerve disorder, but whether it’s rooted in the spinal nerves or peripheral nerves (nerves outside the spine) is not clear.
Many experts believe that this condition is caused by issues with the nerves located in the upper back, specifically the nerves from T2 to T6. This is based on what they’ve seen in some medical scans of patients with notalgia paresthetica. A number of reasons have been identified for these nerve issues, the most common being age-related changes in the spine and slipped spinal discs. Other reasons include bone arthritis causing a humpback posture and excessive bone growth along the spine. However, some medical experts question this theory as nerve issues in the spine would typically cause symptoms in a specific pattern associated with each nerve, rather than just in one area, as seen in notalgia paresthetica.
Several other theories suggest that notalgia paresthetica could be due to physical, structural, genetic, metabolic, and infectious causes. Some physical causes can include muscle spasms. These spasms may squeeze nerves responsible for skin sensation and itchiness, causing abnormal nerve signals. Some believe the angle at which nerves sensitive to histamine (a substance involved in allergic reactions) pass through the spine muscles might make them susceptible to irritation from normal muscle contractions and spasms. It’s thought that physical therapy can help change the muscle tension and alter the angle, leading to decreased nerve irritation and less itchiness. Other less frequent causes include genetic disorders like MEN2A – a type of endocrine system disorder, metabolic diseases like type 2 diabetes, and infections like shingles.
Risk Factors and Frequency for Notalgia Paresthetica
Chronic pruritus, also known as chronic itching, is a wide-ranging category that affects over 20% of people at some point in their lives. A subtype of this condition is called notalgia paresthetica, which is a type of persistent itch related to nerve damage or irritation. This type of chronic itch accounts for about 8% of all cases.
Unlike some other nerve-related itching conditions, notalgia paresthetica doesn’t seem to favor any particular racial or skin color groups. It does show a bias in terms of which side of the body it affects – it typically appears on the opposite side of the person’s dominant hand. This is noteworthy because most people are right-handed. Therefore, if someone has an itch on the left side of their back, which they can reach with their right hand, it’s very possible they have notalgia paresthetica.
In terms of gender differences, it seems women are more likely to have notalgia paresthetica than men, although we should take this with a grain of salt due to the small sizes of the studies conducted so far.
Signs and Symptoms of Notalgia Paresthetica
Notalgia paresthetica is diagnosed mainly through a person’s health history and a physical exam, with a special focus on avoiding unnecessary tests. This condition typically presents with symptoms like long-term, intermittent itching of varying intensity, usually located near the middle or lower area of the shoulder blade on the opposite side of the dominant hand. Although it often affects only one side, it can occur on both sides. Other symptoms might include feelings of pain, heat, cold, a foreign body, tingling, and numbness.
It is more commonly seen in middle-aged women, but men and individuals of various ages can also be affected. There is no preference for race or geographic location.
Unlike other conditions that cause chronic itchiness, notalgia paresthetica doesn’t present a primary skin lesion. However, with long-term itchiness, secondary lesions like darkened skin and a thickened skin surface may become visible. Deep scratches are a tell-tale sign of chronic itching due to nerve issues.
Patients may unconsciously scratch the area while distracted or asleep, which can make symptoms worse. The itchiness is generally located on the middle to lower part of the shoulder blade on the side opposite the dominant hand. Thus, the Apley’s scratch test serves as a basic exam for this condition. In the Apley’s scratch test, one of the tasks is to reach behind the back to touch the lower angle of the shoulder blade on the opposite side. People with notalgia paresthetica should be able to accomplish this task.
Testing for Notalgia Paresthetica
Notalgia paresthetica, a condition characterized by an itchy and sometimes painful patch on your back, can usually be identified by your doctor through a detailed examination and understanding of your medical history. In most cases, additional tests aren’t needed.
Boosting diagnostics with imaging studies such as X-rays, computed tomography (which are special X-ray tests that produce cross-sectional images of the body), or magnetic resonance imaging (a type of imaging that uses magnetic fields and radio waves to create detailed images of the body) typically isn’t required. These imaging tests would only be used if you’re also experiencing muscle or nerve problems besides notalgia paresthetica.
Therefore, identifying notalgia paresthetica is primarily done through a thorough assessment of your medical history and a physical examination conducted by your doctor.
Treatment Options for Notalgia Paresthetica
Notalgia paresthetica is a condition that can be treated in many ways. Treatments include oral and topical medications, a type of toxin called botulinum toxin A, a type of nerve stimulation therapy called transcutaneous electrical nerve stimulation (TENS), and physical therapy. These treatments have different success rates, which can vary from person to person. Before starting treatment, it’s important to reassure the patient that their condition is harmless. Often, this provides enough comfort, and people with mild or occasional itchiness may require no treatment.
The most frequently used treatment for notalgia paresthetica is oral medication. Drugs that affect chemical substances in the brain known as gamma-amino-butyric acid (GABA), serotonin, histamine, and inflammation have been tested. Gabapentin appears to be the most effective drug in reducing itchiness. While taking gabapentin, some patients may experience mild stomach discomfort, but this seldom leads to the discontinuation of the medication. On the other hand, medicines that work on serotonin and inflammation are less effective. Antihistamines, drugs that block a substance involved in allergic reactions, usually don’t provide significant itchiness relief, but may help reduce scratching at night or when distracted due to their sedative effects.
Topical medications, ones that you apply to your skin, are also common. These include capsaicin, steroids, anesthetics, a combination of drugs called amitriptyline/ketamine, and doxepin. Capsaicin is applied most frequently and is available in many forms including creams, gels, solutions, and patches. Even though capsaicin can bring immediate relief, the duration of its effects can vary. It may also cause a burning sensation on the skin. In a small study, it was found to be less effective than gabapentin for treating notalgia paresthetica. The use of steroids, anesthetics, amitriptyline/ketamine, and doxepin is not as widespread and their effectiveness may vary.
Botulinum toxin A is another type of treatment with varying success rates. Initial reports suggested that it could significantly improve itchiness. However, later studies showed little to no improvement.
TENS, a type of nerve therapy, has been reported as successful in treating notalgia paresthetica in a study from Turkey. TENS is usually used to treat nerve pain. It’s thought to target the same nerve pathway responsible for transmitting both itchiness and pain. According to a small study, using TENS for 20 minutes five times a week resulted in a 60% reduction of itchiness in about a third of the patients. However, one out of five patients noticed no difference, and one patient’s itchiness worsened with TENS. Since notalgia paresthetica can include other nerve symptoms like pain, tingling, and numbness in addition to itchiness, TENS might be an especially effective treatment for patients experiencing multiple nerve sensations.
Physical therapy aimed at strengthening the muscles in the upper back and stretching the chest muscles has effectively reduced itchiness in a few cases. This can be particularly useful for patients who have weak back muscles or limited shoulder movement. This type of exercise reduces the angle at which skin nerves go through the back muscles, leading to less irritation and itchiness.
If the itchiness is severe or doesn’t respond to treatment or if the patient also has other musculoskeletal or nerve symptoms along with notalgia paresthetica, they may be referred to a specialist for a more detailed examination.
What else can Notalgia Paresthetica be?
There are several conditions with symptoms similar to notalgia paresthetica. These can sometimes lead to confusion in identifying the correct condition. They include:
- Pigmented contact dermatitis
- Patchy parapsoriasis
- Neurodermatitis
- Early cutaneous amyloidosis
- Tinea versicolor
What to expect with Notalgia Paresthetica
Notalgia paresthetica, despite how it’s treated, usually doesn’t get completely better, but it can be managed, and there’s a chance it could completely go away. While it isn’t a threat to someone’s life, the skin-related symptoms often negatively impact a person’s quality of life, causing discomfort and inconvenience.
Possible Complications When Diagnosed with Notalgia Paresthetica
Notalgia paresthetica can cause various side effects. One of the risks is secondary skin infection, which can occur when the skin’s natural defenses are weakened. The condition can also lead to excessive scratching, resulting in sores on the skin. Other possible complications include skin conditions such as lichen amyloid, a rare skin disorder that causes itchy, firm bumps to form on the skin, lichen simplex chronicus, a skin disorder that causes thick, itchy skin, and prurigo nodules, hard, itchy lumps.
Potential Side Effects:
- Secondary skin infection
- Excoriations due to excessive scratching
- Lichen amyloid
- Lichen simplex chronicus
- Prurigo nodules
Preventing Notalgia Paresthetica
It’s important for patients to know that notalgia paresthetica, a condition that causes an intense itching in the back, is pretty common and isn’t serious. However, it may take a very long time to fully disappear. Therefore, it’s crucial for patients to follow all treatments faithfully. This includes the use of moisturizing creams (emollients), inflammation reducing creams (steroids), and numbing medications (anesthetics). It’s essential to stick with these treatments, even if immediate results aren’t visible, as they may still be helping to improve the condition over time.
