Sir, A middle aged female complained of certain sensations on the back in the subscapular region. On clinical examination, there was a circumscribed, hyperpigmented patch. A provisional diagnosis of notalgia paresthetica was made (<xref ref-type="fig" rid="F1">Fig. 1</xref>). Dermoscopy was performed using a Dermlite DL3N at 10x magnification under polarised light. <fig id="F1"> <label>Figure 1</label> <caption> A case of notalgia paresthetica in a middle aged patient. </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-10-317-g001.tif"/> </fig> Dermoscopy of this patch revealed alternating patches of hyperpigmentation and hypopigmentation (<xref ref-type="fig" rid="F2">Fig. 2a</xref>). The hyperpigmented patches were brown to slate gray in colour and were present in various forms. They were arranged in an irregular net like pattern. In some areas the pigmentation was scattered with various patterns around a central hub which was either hypopigmented or hyperpigmented. Shiny white streaks were observed within the hypopigmented patches (<xref ref-type="fig" rid="F3">Fig. 2b</xref>). <fig id="F2"> <label>Figure 2a</label> <caption> Dermoscopic overview shows alternate hypopigmented and hyperpigmented patches throughout the lesion. </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-10-317-g002.tif"/> </fig> <fig id="F3"> <label>Figure 2b</label> <caption> Hyperpigmented patches are brown or slate gray in color. The pigment pattern may take the formation of irregular nets (black arrow), may have central hypopigmented hub (red arrow) or hyperpigmented hub (yellow arrow) surrounded by pigment configurations of different shapes and patterns. Shiny white streaks are also seen (blue arrow). </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-10-317-g003.tif"/> </fig> Notalgia paresthetica occurs due to nerve root entrapment of T2-T6 rami causing paresthesia resulting in chronic itching and friction. This friction leads to degeneration of keratinocytes and deposition of amyloid fibrils in cases of notalgia paresthetica. Amyloid fibrils are abnormally polymerised cytokertain derived material. These fibrils are birefringent and under polarised dermoscopy appear as shiny white streaks [<xref ref-type="bibr" rid="ref1">1</xref>]. Thus, shiny white streaks in notalgia paresthetica correspond histologically to amyloid fibrils [<xref ref-type="bibr" rid="ref2">2</xref>]. Hyperpigmentation of various patterns seen dermoscopically corresponds to either basal pigmentation of the epidermis or melanophages with pigment incontinence in the dermis. Due to its presentation, notalgia paresthetica may mimic macular amyloidosis not only clinically but also dermoscopically. However, shiny white streaks are absent in macular amyloidosis on dermoscopy providing a vital dermoscopic clue in differentiating the two conditions. <sec id="sec2-1"> <title>Consent

Our Dermatol Online

2081-9390

Our Dermatology Online

Poland

OURD-10-317

10.7241/ourd.20193.31

Letter to the Editor

Dermoscopy of notalgia paresthetica

Malakar

Subrata

1 Mehta

Purva

2 Malakar

Surit

1Medical Director, Rita Skin Foundation, Kolkata, India 2Consultant Dermatologist, Rita Skin Foundation, Kolkata, India 3Consultant Dermatologist, Rita Skin Foundation, Kolkata, India

Corresponding author: Dr. Purva Mehta, E-mail: purvamehta86@gmail.com

2019

10 3 318 317 24092018 13122018

2019

This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Sir, A middle aged female complained of certain sensations on the back in the subscapular region. On clinical examination, there was a circumscribed, hyperpigmented patch. A provisional diagnosis of notalgia paresthetica was made (<xref ref-type="fig" rid="F1">Fig. 1</xref>). Dermoscopy was performed using a Dermlite DL3N at 10x magnification under polarised light. <fig id="F1"> <label>Figure 1</label> <caption> A case of notalgia paresthetica in a middle aged patient. </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-10-317-g001.tif"/> </fig> Dermoscopy of this patch revealed alternating patches of hyperpigmentation and hypopigmentation (<xref ref-type="fig" rid="F2">Fig. 2a</xref>). The hyperpigmented patches were brown to slate gray in colour and were present in various forms. They were arranged in an irregular net like pattern. In some areas the pigmentation was scattered with various patterns around a central hub which was either hypopigmented or hyperpigmented. Shiny white streaks were observed within the hypopigmented patches (<xref ref-type="fig" rid="F3">Fig. 2b</xref>). <fig id="F2"> <label>Figure 2a</label> <caption> Dermoscopic overview shows alternate hypopigmented and hyperpigmented patches throughout the lesion. </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-10-317-g002.tif"/> </fig> <fig id="F3"> <label>Figure 2b</label> <caption> Hyperpigmented patches are brown or slate gray in color. The pigment pattern may take the formation of irregular nets (black arrow), may have central hypopigmented hub (red arrow) or hyperpigmented hub (yellow arrow) surrounded by pigment configurations of different shapes and patterns. Shiny white streaks are also seen (blue arrow). </caption> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="OURD-10-317-g003.tif"/> </fig> Notalgia paresthetica occurs due to nerve root entrapment of T2-T6 rami causing paresthesia resulting in chronic itching and friction. This friction leads to degeneration of keratinocytes and deposition of amyloid fibrils in cases of notalgia paresthetica. Amyloid fibrils are abnormally polymerised cytokertain derived material. These fibrils are birefringent and under polarised dermoscopy appear as shiny white streaks [<xref ref-type="bibr" rid="ref1">1</xref>]. Thus, shiny white streaks in notalgia paresthetica correspond histologically to amyloid fibrils [<xref ref-type="bibr" rid="ref2">2</xref>]. Hyperpigmentation of various patterns seen dermoscopically corresponds to either basal pigmentation of the epidermis or melanophages with pigment incontinence in the dermis. Due to its presentation, notalgia paresthetica may mimic macular amyloidosis not only clinically but also dermoscopically. However, shiny white streaks are absent in macular amyloidosis on dermoscopy providing a vital dermoscopic clue in differentiating the two conditions. <sec id="sec2-1"> <title>Consent

The examination of the patient was conducted according to the Declaration of Helsinki principles.

REFERENCES 1

Arnold

Bowling

'Shiny white streaks'in lichen amyloidosis: A clue to diagnosis

Australas J Dermatol 2012 53 272 3

Shin

Kim

Neuropathic Itch of the Back: A Case of Notalgia Paresthetica

Ann Dermatol 2014 26 392 4

Source of Support: Nil

Conflict of Interest: None declared.