Notalgia paresthetica

{{short description|Neuropathy causing itching between the shoulder blades}}

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Notalgia paresthetica or Notalgia paraesthetica (NP) (also known as "Hereditary localized pruritus", "Posterior pigmented pruritic patch", and "subscapular pruritus"{{cite book |author=Rapini, Ronald P. |author2=Bolognia, Jean L. |author3=Jorizzo, Joseph L. |title=Dermatology: 2-Volume Set |publisher=Mosby |location=St. Louis |year=2007 |isbn=978-1-4160-2999-1 }}) is a chronic sensory neuropathy. Notalgia paresthetica is a common localized itch, affecting mainly the area between the shoulder blades (especially the T2–T6 dermatomes) but occasionally with a more widespread distribution, involving the shoulders, back, and upper chest.Freedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. {{ISBN|0-07-138076-0}}.{{rp|402|date=November 2012}} The characteristic symptom is pruritus (itch or sensation that makes a person want to scratch) on the back, usually on the left hand side below the shoulder blade (mid to upper back). It is occasionally accompanied by pain, paresthesia (pins and needles), or hyperesthesia (unusual or pathologically increased sensitivity of the skin to sensory stimuli, such as pain, heat, cold, or touch), which results in a well circumscribed hyperpigmentation of a skin patch in the affected area.

Causes

The causes of this condition have not yet been completely defined.{{cite journal|title=ingentaconnect Notalgia paresthetica: a study on pathogenesis |journal=International Journal of Dermatology |volume=39 |issue=10 |pages=754–9 |publisher=Ingentaconnect.com |date=2000-10-01 |doi=10.1046/j.1365-4362.2000.00080.x |pmid=11095194 |last1=Savk |first1=E. |last2=Savk |first2=O. |last3=Bolukbasi |first3=O. |last4=Culhaci |first4=N. |last5=Dikicioğlu |first5=E. |last6=Karaman |first6=G. |last7=Sendur |first7=N. |s2cid=24030363 }} Patients are usually older persons.{{Cite web | url=http://www.skinsight.com/adult/notalgiaParaesthetica.htm |title = Skinsight - Notalgia Paraesthetica}}

The correlation of notalgia paresthetica localization with corresponding degenerative changes in the spine suggests that spinal nerve impingement may be a contributing cause. According to Plete and Massey, "The posterior rami of spinal nerves arising in T2 through T6 are unique in that they pursue a right-angle course through the multifidus spinae muscle, and this particular circumstance may predispose them to harm from otherwise innocuous insults of a varied nature." Patients may have other conditions that predispose them to peripheral neuropathies (nerve damage).{{cn|date=July 2021}}

Diagnosis

Possible differential diagnoses are:{{cite web | url=https://emedicine.medscape.com/article/1599159-differential | title=Notalgia Paresthetica Differential Diagnoses }}

Treatment

Therapy for notalgia paresthetica is directed at controlling symptoms, as no cure exists for the condition. Available treatments include local anesthetics, topical capsaicin,{{Cite journal|last1=Andersen|first1=H. H.|last2=Arendt-Nielsen|first2=L.|last3=Elberling|first3=J.|date=July 2017|title=Topical capsaicin 8% for the treatment of neuropathic itch conditions|journal=Clinical and Experimental Dermatology|volume=42|issue=5|pages=596–598|doi=10.1111/ced.13114|issn=1365-2230|pmid=28556308|s2cid=3813025}}{{Cite journal|last1=Andersen|first1=Hjalte H.|last2=Sand|first2=Carsten|last3=Elberling|first3=Jesper|date=February 2016|title=Considerable Variability in the Efficacy of 8% Capsaicin Topical Patches in the Treatment of Chronic Pruritus in 3 Patients with Notalgia Paresthetica|journal=Annals of Dermatology|volume=28|issue=1|pages=86–89|doi=10.5021/ad.2016.28.1.86|issn=1013-9087|pmc=4737841|pmid=26848223}} topical corticosteroids,Journal of the American Academy of Dermatology Volume: 32 Issue: 2 Pages: 287–289 Part: Part Published: FEB 1995 ISSN {{ISSN link|0190-9622}} hydroxyzine, oxcarbazepine, palmitoylethanolamide and gabapentin. Paravertebral nerve block and botulinum toxin injections may also be helpful.

Some patients treated with low concentration topical capsaicin reported pain, burning, or tingling sensations with treatment, and symptoms returned within a month of ceasing treatment.{{cite journal|title=JAMA Network | JAMA Dermatology | Successful Treatment of Notalgia Paresthetica With Botulinum Toxin Type A |journal=Archives of Dermatology |volume=143 |issue=8 |pages=980–982 |publisher=Archderm.ama-assn.org |date=2006-10-16 |doi=10.1001/archderm.143.8.980 |pmid=17709655 |last1=Weinfeld |first1=Pamela Kirschner |doi-access=free }} Oxcarbazepine was reported to reduce the severity of symptoms in a few cases.JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY Volume: 45 Issue: 4 Pages: 630-632 Published: OCT 2001 ISSN {{ISSN link|0190-9622}} One patient has been treated with "paravertebral nerve blocks, with bupivacaine and methylprednisolone acetate injected into the T3–T4 and T5–T6 intervertebral spaces" JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY Volume: 38 Issue: 1 Pages: 114-116 Published: JAN 1998 ISSN {{ISSN link|0190-9622}} Hydroxyzine has also been used with considerable success in some cases as long as the pills are used daily.

High concentration topical capsaicin (8%, Qutenza) have been shown to be highly effective in treating neuropathic itch in some patients{{Cite journal|last1=Andersen|first1=Hjalte H.|last2=Sand|first2=Carsten|last3=Elberling|first3=Jesper|date=February 2016|title=Considerable Variability in the Efficacy of 8% Capsaicin Topical Patches in the Treatment of Chronic Pruritus in 3 Patients with Notalgia Paresthetica|journal=Annals of Dermatology|volume=28|issue=1|pages=86–89|doi=10.5021/ad.2016.28.1.86|issn=1013-9087|pmc=4737841|pmid=26848223}}{{Cite journal|last1=Andersen|first1=H. H.|last2=Arendt-Nielsen|first2=L.|last3=Elberling|first3=J.|date=July 2017|title=Topical capsaicin 8% for the treatment of neuropathic itch conditions|journal=Clinical and Experimental Dermatology|volume=42|issue=5|pages=596–598|doi=10.1111/ced.13114|issn=1365-2230|pmid=28556308|s2cid=3813025}} (including notalgia paresthetica) as well as in a recent proof-of-concept study.{{Cite journal|last1=Andersen|first1=H. H.|last2=Marker|first2=J. B.|last3=Hoeck|first3=E. A.|last4=Elberling|first4=J.|last5=Arendt-Nielsen|first5=L.|date=2017-01-24|title=Antipruritic effect of pretreatment with topical capsaicin 8% on histamine- and cowhage-evoked itch in healthy volunteers: a randomized, vehicle-controlled, proof-of-concept trial|journal=The British Journal of Dermatology|volume=177|issue=1|pages=107–116|doi=10.1111/bjd.15335|issn=1365-2133|pmid=28117875|s2cid=13377266}}

Most recently intradermal injections of botulinum toxin type A (Botox) have been tried with some success. Even though botulinum normally wears off in three to six months, the treatment appears to be long term, and it has been theorised that botulinum type A effects lasting change in pain signaling.NEUROTOXICOLOGY Volume: 26 Issue: 5 Special Issue: Sp. Iss. SI Pages: 785–793 Published: OCT 2005 ISSN {{ISSN link|0161-813X}}

References

Pleet, A Bernard and Massey, E Wayne, Notalgia Paresthetica, Neurology, Dec 1978; 28: 1310
Pleet, A Bernard and Massey, E Wayne, Letter to the Editor: Notalgia Paresthetica, Neurology, Vol. 29, Issue 4, 528 April 1, 1979