Dermatology

Notalgia Paresthetica

Notalgia Paresthetica

Are You Confident of the Diagnosis?

What you should be alert for in the history

Be alert for a very localized itch, without a rash, on the upper back for months to years, which may occasionally be bilateral. Patients may also complain of concomitant pain or dysesthesia, but notalgia paresthetica (NP) is seldom the patient’s main reason for their visit.

Characteristic findings on physical examination

The patient can point a finger (if he or she can reach it) to the area of pruritus, classically near the lower-medial border of the scapula, although sometimes higher on the back (Figure 1). Usually there are no skin findings; occasionally there may be mild lichenification; a brown patch consistent with postinflammatory hyperpigmentation; or recent excoriations. Neurocutaneous testing may reveal diminished sensation to pinprick, light touch or temperature sensitivity. Osteopathic-related physicians have noted exacerabtion or alleviation of symptoms with related changes in posture/positioning.

Figure 1.

The patient can usually point to a localized area of pruritus without visible skin changes.

Expected results of diagnostic studies

NP is usually not biopsied, as the diagnosis is made by the above history and lack of cutaneous findings. Histological studies have revealed necrotic keratinocytes, dermal melanin, and melanophages in all patients with hyperpigmentation, and an absence of amyloid on crystal violet staining. Immunohistochemistry has documented increased dermal innervation (but it is unknown whether this is a cause or an effect of NP).

Imaging studies, such as magnetic resonance imaging (MRI) of the spine, have shown correlation of spinal pathology and the NP dermatome(s). Older studies revealed abnormal changes on electromyography (EMG) testing.

Diagnosis confirmation

NP should be distinguished from macular amyloid, which presents as pruritus on the uppermost midback associated with a broad brown-gray pigmented patch. As zoster occurs often on the upper back, postherpetic neuralgia could mimic NP. The fomer would usually have a history of the shingles rash, and the area of dysethesia would tend to be broader Pain would be more prominent than itch. Lichen simplex chronicus (LSC) secondary to other causes should be distinguished from the lichenified stage of NP (example, LSC from a chronic allergic contact dermatitis from the metal clip on the back of a bra).

Who is at Risk for Developing this Disease?

A not uncommon condition, this annoyance is seen monthly in private practice. It usually is not the patient’s main complaint. Patients are usually between 40 and 70 years old. It is more common in women, more common on the left side, and possibly more common in Caucasians.

What is the Cause of the Disease?

Etiology

Pathophysiology

The etiology of NP is not well elucidated. Controversy exists about the role of structural neuroskeletal alterations causing an entrapment syndrome. MRI studies have shown a correlation of spinal-vertebral changes and NP dermatomes in some cases. This study mentioned a large percentage of cervical spine changes, although NP classically involves T2-T6. The importance of this study’s findings is undermined by the high prevalence of MRI findings in asymptomatic individuals. A very recent article demonstrated degenerative changes in the thoracic spine of 47% of asymptomatic subjects. Degenerative changes were found in the cervical spine of 90% of the subjects (who were, on average, younger than the average NP patient).

Other authors have focused on the entrapment of the nerve more distally, specifically of the dorsal rami ofthoracic nerves, T2-T6 as they “exit at right angles” through the back muscles to the skin. Other theories include increased dermal innervation, which has been documented on histopathology, but it is unproven whether this is a cause or an effect ; uncontrolled viscerocutaneous reflex mechanisms secondary to spinal injury; or chemical neurotoxicity.

This author, while downplaying but not ignoring the structural findings, suggests NP is partially a psychosomatic condition, similar to several other forms of localized pruritus without significant cutaneous findings. If nerve compression/entrapment alone was causative, NP would be an epidemic. In reality, millions of people have a multitude of cervicothoracic spinal changes without NP, and most or many NP patients have no relevant spinal pathology.

The psychosomatic theory, more than the nerve compression theory, better explains why patients may have this condition without precipitating factors, and then have it resolve years later without intervention or sequelae. One would suspect that years of nerve entrapment would lead to severe, progressive nerve injury. The psychosomatic theory is coherent with the high placebo rates seen in NP case studies; remarkable remission of chronic NP cases with simple osteopathic manipulation; and dramatically prolonged remission of interventions that have temporary mechanisms. It should be noted that psychosomatic concepts are much more accepted by physicians and patients in Europe and South America than in the United States.

Systemic Implications and Complications

A handful of hereditary cases have been noted, mainly in young patients associated with multiple endocrine neoplasia type 2A. A young patient with NP and a family history of MEN 2A should be aggressively screened for this syndrome.

Treatment Options

Since there is controversy about the pathophysiology of NP, and treatment depends on whether the patient presents to the dermatologist (itch) or an orthopaedic discipline (pain), as well as that physician’s training, treatments may be divided into dermatologic, orthopaedic, or psychosomatic (Table I).

Table I.

Treatment options for notalgia paresthetica
Topical: Physical therapy Patient education of psychosomatic concepts
Emollients Osteopathic manipulation Review patient's biospychosocial history
Pramoxine, Camphor Paravertebral local anesthetic block (bupivicaine and methyprednisolone) Inquire about history of other psychosomatic disorders
Doxepin Transcutaneous electrical nerve stimulation Further patient education: reading. Example:The Divided Mind (2006) by Dr. John E. Sarno
Capsaicin Epidural corticosteroid injection Psychotherapy
Lidocaine/prilocaine Surgical nerve decompression
Modalities:
Intralesional lidocaine
Intralesional botulinum toxin
Ultraviolet B phototherapy
Oral:
Gabapentin
Oxcarbazine

Optimal Therapeutic Approach for this Disease

Dermatologic

Explain the natural history of NP to the patient so that they understand this is a not uncommon but rather benign, odd affliction that may resolve even after a prolonged time without any treatment.

Encourage emollients for xerosis, especially in this older population, as xerosis may compound the pruritus of NP. Mild cases can be initially treated with pramoxine or camphor. While never studied in NP, topical doxepin hydrochloride 5% cream has been proven to diminish pruritus in four large, randomized, double-blind, placebo-controlled clinical trials (for atopic dermatitis or lichen simplex chronicus). Because of the small size of NP along with its intact skin barrier, the otherwise common side effects of sedation or irritation are usually not evident. Cost may be a factor as insurance coverage is often limited. Doxepin may be applied thinly, thrice daily.

Topical capsaicin is the only treatment of NP shown to be effective in a prospective, randomized fashion. In a cross-over study, capsaicin reduced symptoms 41% compared to 19% from the vehicle in the first part of the study. The study did not allow for an adequate washout period; however, capsaicin reduced symptoms by 48% compared to 11% from the vehicle after the cross-over. Unfortunately, a plain vehicle is not an adequate placebo as it does not create the expected burning that capsaicin provides during the first week of treatment.

Of note, the authors only listed the results of one of two study parameters, suggesting that efficacy was not demonstrable by the second outcome measure. The overall placebo rate was felt to be 30%. Most patients had a relapse within 1 month. In a previous case series by the same authors, some patients did well for 9 months. Capsaicin 0.025% cream was applied to the symptomatic area five times a day during the first week and three times a day during the subsequent 3 weeks. When using capsaicin, another option is to start with only two or three applications a day for the first week or so to minimize the initial burning. On the other hand, the burning could arguably increase the placebo effect.

Topical anesthetics such as 5% lidocaine/prilocaine gel may provide short-term relief. It may be applied as necessary. Some patients may prefer an intradermal or deeper injection of 1% lidocaine with or without triamcinolone solution 5 mg/ml. (Local anesthetics have membrane-stabilizing properties that can reduce the repetitive neuronal firing in neuropathic states. Corticosteroids are also membrane stabilizers and can suppress ectopic neural pacemaker activity.)

If cost is not a factor, intradermal injections of botulinum toxin appear to be a safe, simple and long-lasting new treatment for NP. In “The Cutting Edge” section of Archive of Dermatology, two patients were treated. After 18 months, one patient was symptom-free and the other had only mild intermittant pruritus. Time will tell if the unusually long duration of symptom relief, which has also been demonstrated in other pain syndromes, is due to altered feedback loops leading to changes in pain signaling or a placebo effect.

The author used a common injection protocol: The area to be treated was demarcated based on history and examination. Using a 3-ml dilution with preserved (0.9%) saline, 4 units of botulinum toxin type A were injected superfically 2 cm apart. Dosages ranged from 16 to 48 units. Currently, botulinum toxin for NP is being investigated in a prospective, double-blind Canadian trial.

One series of five patients had partial or complete remission with narrowband ultraviolet B (UVB) phototherapy. This therapy was attempted given the effectiveness of UVB radiation in the treatment of some forms of pruritus; phototherapy may reduce the number of epidermal nerve fibers. Patients were treated thrice weekly with a standard dosing protocol. Remission or resolution was achieved with an average of 33 sessions and a mean cumulative dose of 34 J/cm2. It would be interesting to see the effects of an excimer laser which would be able to quickly treat the small lesion size with more aggressive dosages.

Gabapentin, used for many disorders with neuropathic pain or dysesthesia, successfully suppressed the pruritus of NP in one patient. Symptoms recurred after discontinuation and remitted after reinstitution of the medication. A reasonable starting dose is 300mg at bedtime, which may be increased to 600mg nightly after several weeks if required. Higher dosages, up to 3600mg a day, should be divided into thrice daily dosing.

Oxcarbazine is used for trigeminal neuralgia as well as seizures and bipolar disorder. In a series of five patients with NP, three had a partial response (one patient discontinued the medication due to side effects). All patients were started on 300mg twice daily, and the dosage was increased to 600mg twice daily after 2 weeks depending on response. The highest dose of the four patients was 900mg twice daily; however, for its other indications the maximum dose is 1200mg twice daily. Side effects may be the limiting factor.

Orthopaedic

See list above for possible treatment options for the appropriate neurologist or orthopaedic specialist.

Psychsomatic

Educate the patient concerning the possible psychosomatic origin of many medical conditions. Explain that the mind and body are connected, and that the mind, particulary the unconscious mind, can initiate or exacerbate medical conditions. ’Stress’ is a term of the conscious mind. Patients do not have to get rid of stress, they just have to understand its link to health or lack of health. Inquire about other medical conditions that might be psychosomatic. Review their biopsychosocial history for stressors, both recent, cumulative, and particularly childhood.

Patients who are interested in this concept may read relevant books such as The Divded Mind by Dr. John E. Sarno (2006) or check out related websites. A handful of patients may be interested in and benefit from psychotherapy. This is preferable to psychopharmacology, and patients should be referred to a psychologist (Psy.D. or Ph.D.) rather than a psychiatrist (M.D.).

Patient Management

Explain the variable but benign nature of NP. Educate them that despite even a long course it may resolve without treatment or sequelae. Inform them that it is not dangerous; hence, the benefit of any potential systemic treatment or orthopeadic intervention must be carefully weighed against potential risks.

If the patient’s symptoms become severe or painful an MRI is warranted to rule out unlikely significant spinal pathology (eg,. tumor, mass).

Unusual Clinical Scenarios to Consider in Patient Management

A handful of hereditary cases have been noted, mainly in young patients associated with multiple endocrine neoplasia type 2A. A young patient with NP and a family history of MEN 2A should be aggressively screened for this syndrome.

What is the Evidence?

Weber, PJ, Poulos, EG. "Notalgia paresthetica: Case reports and histological appraisal". J Am Acad Dermatol . vol. 18. 1988. pp. 25-30.

(A pathological study of 14 cases revealed the consistent histological findings of NP and reviewed the pathologic changes of disorders that may be confused with NP. The authors highlight the underappreciated neurocutaneous findings of NP such as decreased pinprick, light touch, and temperature sensitivity. Treatment is not discussed.)

Savk, O, Savk, E. "Investigation of spinal pathology in notalgia paresthetica". J Am Acad Dermatol . vol. 52. 2005. pp. 1085-7.

(This Ortho-Derm Turkish tandem is at the forefront of the concept that NP is caused by nerve entrapment due to musculoskeletal anomalies. In this study, the largest ever reported on NP, they demonstrate a correlation between vertebral pathology and NP dermatomes. Evaluation of these intriging findings is hindered by the lack of case details and imaging pictures.)

Matsumoto, M, Okada, E, Ichihara, D, Watanabe, K, Chiba, K, Toyama, Y. "Age-related changes of thoracic and cervical intervertebral discs in asymptomatic subjects". Spine . vol. 35. 2010. pp. 1359-64.

(This recent article showed that if you study 100 people walking around without any back/neck problems, half will have degenerative changes in the thoracic spine and 90% will have degenerative changes in the cervical spine. The changes included decreased signal intensity of the intervertebral discs, disc protrusion, anterior compression and disc space narrowing.)

Hillard, JR, Rockwell,, WJK. "Dysesthesia, witchcraft, and conversion reaction: a case successfully treated with psychotherapy". JAMA. vol. 240. 1978. pp. 1742-4.

(While the authors were not aware of the nomenclature of their patient’s symptoms; these psychiatrists describe a classic case of notalgia paresthetica. The patient’s symptoms persisted for 2 years despite multiple physicians and treatments. She had a normal thoracic myelogram, and after recognizing a placebo response, she was referred to psychiatry. Her biopsychosocial history revealed a belief in witchcraft (root work) and that the onset of her symptoms started after her father’s death. After recognizing her NP was a conversion reaction, she was cured by psychotherapy.)

Eschler, DC, Klein, PA. "An evidence-based review of the efficacy of topical antihistamines in the relief of pruritus". J Drugs Dermatol . vol. 9. 2010. pp. 992-7.

(This recent article summarizes (and critiques) the four “Grade A” studies showing statistically significant effects of doxepin versus placebo, despite a high placebo rate, for atopic dermatitis or lichen simplex chronicus.

Wallengren, J, Klinker, M. "Successful treatment of notalgia paresthetica with topical capsaicin: vehicle-controlled, double-blind, crossover study". J Am Acad Dermatol . vol. 32. 1995. pp. 287-9.

The authors study the use of capsaicin, as pain and itch are transmitted through C-fibers, and capsaicin releases neuropeptides from these C-fibers. Capsaicin was superior to the vehicle; however, since a plain vehicle is not an adequate placebo for capsaicin, this study was not really vehicle-controlled or double-blinded. Recurrences were seen earlier than in a previous series by these authors.)

Gooding, SMD, Canter, PH, Coelho, HF, Boddy, K, Ernst, E. "Systematic review of topical capsaicin in the treatment of pruritus". Int J Dermatol . vol. 49. 2010. pp. 858-65.

(A very recent review analyzing topical capsaicin studies for treating pruritus in any medical condition concludes there is no convincing evidence for its use. Their conclusions were based mainly on suboptimal study design (including the difficulty in finding an adequate placebo for the chile pepper extract). Of note, they include a study done by the same lead author above using capsaicin for brachioradial pruritus. In that study, there was no significant difference and the placebo reduced itching by 65%.)

Weinfeld, PK. "Successful treatment of notalgia paresthetica with bolulinum toxin type A". Arch Dermatol . vol. 143. 2007. pp. 980-2.

Over the last several years, the antinociceptive effects of botulinum toxin have become recognized. This author had excellent long-term results in two patients with this simple treatment, similar to those obtained through its use in other pain/itch conditions.

Loosemoore, MP, Bordeaux, JS, Bernhard, JD. "Gabapentin treatment for notalgia paresthetica, a common isolated peripheral sensory neuropathy". J Eur Acad Dermatol Venereol . vol. 21. 2007. pp. 1440-1.

(A successful case report using gabapentin for NP. It has also been used in brachioradial pruritus, which this patient also had. The main side effects include sedation and gastrointestinal upset.)

Savk, E, Bolukbasi, K, Akyol, A, Karaman, G. "Open pilot study of oxcarbazine for the treatment of notalgia paresthetica". J Am Acad Dermatol . vol. 45. 2001. pp. 630-2.

(Oxcarbazine is a derivative of carbamazapine, which is an anticonvulsant and an analgesic. It has an improved side effect profile, but side effects may still be a limiting factor for some patients. The lead author of this study is an expert in NP. In this series of five patients, three patients got a partial reduction in symptoms; pruritus, pain or paresthesia. As the results were only partial, patients were maintained on therapy during the study period of 6 months.)
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