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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 14  |  Issue : 5  |  Page : 172-174  

Scanning electron microscopy of the inner and outer aspects of tiger tail hairs


1 Catholic University of Pelotas, Post-Graduation Program in Health; Dermatology League, Federal University of Pelotas, Pelotas, Brazil
2 Catholic University of Pelotas, Post-Graduation Program in Health, Pelotas, Brazil
3 Dermatology League, Federal University of Pelotas, Pelotas, Brazil
4 Electron Microscopy Laboratory, EMBRAPA-CPA-CT, Pelotas, Brazil
5 Electron Microscopy Center, Fundação University of Rio Grande, Brazil

Date of Submission19-Apr-2020
Date of Decision19-Jul-2020
Date of Acceptance09-Mar-2022
Date of Web Publication07-Oct-2022

Correspondence Address:
Hiram Larangeira de Almeida
Rua Gonçalves Chaves 373, Pelotas
Brazil
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijt.ijt_63_20

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   Abstract 


Background: Tiger tail hairs, Morse hairs or pili annulati is a nonsyndromic hair shaft disorder, characterized by alternating light and dark bands along the hair shaft. Methods: The outer surface and the inner structure of longitudinally cut tiger tail hairs were examined with scanning electron microscopy. Results: Hair specimens of five affected individuals showed small surface undulations with “curtain-like” folding of the hair cuticula (microcanaliculi). In the inner surface cord-like linear structures with serpiginous, tortuous traject were seen, associated with some cavities. Conclusions: These findings suggest that this condition is due to some deficient protein synthesis/arrangement, not only due to cavities in the hair cortex. The term Tiger tail hair is a descriptive clinical term of little scientific rigor. This disorder has been reported mainly as pili annulati; however, rings are not observed. In analogy to pili canaliculi, in which well-formed grooving is observed in the hair surface, we suggest the term pili microcanaliculi to describe this condition, based in the ultrastructural findings.

Keywords: Pili annulati, scanning electron microscopy, tiger tail hairs


How to cite this article:
de Almeida HL, Göebel Pinto JB, de Almeida AL, de Castro LA, Ruas CP. Scanning electron microscopy of the inner and outer aspects of tiger tail hairs. Int J Trichol 2022;14:172-4

How to cite this URL:
de Almeida HL, Göebel Pinto JB, de Almeida AL, de Castro LA, Ruas CP. Scanning electron microscopy of the inner and outer aspects of tiger tail hairs. Int J Trichol [serial online] 2022 [cited 2022 Dec 7];14:172-4. Available from: https://www.ijtrichology.com/text.asp?2022/14/5/172/358103




   Introduction Top


Tiger tail hairs (TTH), Morse hairs, or pili annulati is a nonsyndromic hair shaft disorder,[1] characterized by alternating light and dark bands along the hair shaft, which appears shiny and speckled.[2],[3],[4],[5],[6],[7] This aspect may result from an increased light reflex caused by abnormal air-filled cavities within the hair shaft's cortex described with transmission electron microscopy.[8],[9] TTH etiology is still uncertain. It is an autosomal dominant condition with variable expression;[1] some sporadic cases have also been reported.

TTH is commonly found in the hair of the scalp, but other regions such as pubic, axillary, and beard hair, may also be affected.[6]

Few studies in the literature associate TTH with other systemic or cutaneous changes.[10] The origin of this association, when existing, has been a constant source of debate.

Its diagnosis is based on microscopic examinations of the hair shaft, such as with light microscopy.[2]

Scanning electron microscopy (SEM) is an important instrument for the examination of hair shaft anomalies. Although there are published reports of its use, most of the studies focusing on the use of SEM in TTH cases describe images of the hair surface, and few studies used cross-sections of the inner structure of the hair shaft.

The purpose of the present study was to describe ultrastructural findings of TTH, using SEM examining the outer and the inner structure of longitudinally cut hairs.


   Methods Top


We examined hair specimens from six individuals of the same family, from three different generations, presented with characteristic light and dark bands, the so-called “tiger tail.” It was first reported by the hairdressers while the individuals were having a haircut. The grandmother, her two daughters, and three grandchildren were examined and only one granddaughter was clinically unaffected, demonstrating an autosomal dominant trait. The outer hair surface from all six individuals was examined in natura using SEM, esthetic procedures, such as dyeing or straightening, were not used by the patients.

Hair specimens of the grandmother and from an affected daughter were embedded in resin and sliced up to reach the inner portion. The resin blocks with the hairs were metalized and also examined with SEM. Two hairs from two unaffected controls were also submitted to the same procedure, and its inner surface was also examined.


   Results Top


Scanning electron microscopy of the outer surface

Hair specimens of the five affected individuals showed small surface undulations with “curtain-like” folding of the hair cuticula. The intensity of the findings was considered mild in four individuals [Figure 1]a and more intense in the older patient [Figure 1]b. With high magnifications, the superficial canaliculation of the hair cuticula could be better demonstrated [Figure 1]c and [Figure 1]d.
Figure 1: Outer hair surface with (a) undulations on the hair surface (×220) and (b) undulations with a normal area in the center (×400). (c and d) Higher magnifications showing in detail the microcanaliculi in the hair cuticula (×1000 and × 1900)

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Scanning electron microscopy of the inner surface

With low magnifications, we could determine that the hair cortex was achieved and exposed by the cut. In both cases examined, there was a change of parallelism of the structures found in the inner surface.

Although probable artifactual indentations are observed, clearly cord-like linear structures with serpiginous, tortuous traject were seen in many fields [Figure 2]a, [Figure 2]b, [Figure 2]c. Small cavities can be observed in some areas [Figure 2]c.
Figure 2: Inner hair aspect with (a) serpiginous cord-like structure (arrows) in the hair cortex, note in the center one cord-like structure with a regular linear distribution (arrow heads) (×8000) and (b) undulated cord-like structure (arrows) (×8000). (c) Cord-like structures with irregular distribution (arrows), on the inferior part with regular distribution (arrowheads), and an incipient cavity (asterisk) (×9500). (d) Normal control without changes (×8000)

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In normal controls, the SEM of the inner surface showed a dense and parallel arrangement of the hair keratin [Figure 2]d.

Very high magnifications of the affected hairs show small cavities in the hair cortex and the serpiginous traject of some hair structures [Figure 3].
Figure 3: High magnification of the inner aspect with detail of the serpiginous structure (arrows) and a cavity (asterisk) (×11,000)

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   Discussion Top


Previous studies with SEM of the hair surface showed an intermittent pattern of grooves or longitudinal undulations,[8],[9] with variable cuticular damage, revealing a “cobblestoned” or “curtain-like” aspect, in accordance with the findings of this particular family.

These undulations probably correspond to the area underlying the air-filled cavities within the hair shaft's cortex.

Association with hair fragility is variable in the reported cases,[11] when there is associated hair breakage, there may be cracks within the grooves at the cuticular level, and exposure of macrofibrils,[4] association with severe trichorrhexis nodosa was already reported.[12] In the cases examined here, there were neither ultrastructural signs of fragility nor history of hair breakage.

The findings corresponding to the ultrastructure of the inner portion of the hairs showed important irregularity in the parallel arrangement of proteins that form the hair cortex. Some of the parallel lines shown in [Figure 2] could be a cutting artifact but not the serpiginous, irregular distribution of some hair proteins.

This abnormal protein arrangement could lead to the formation of the described cavities leading to the changed optical effect, and in more severe cases, to the fragility with hair breakage. Our findings suggest that TTH is due to some deficient protein synthesis/arrangement, not only due to cavities in the hair cortex, these findings should be confirmed at the protein level since ultrastructural studies with electron microscopy can only describe morphological changes.

We found reports of the use of SEM in cross-sections of TTH but not in longitudinal cuts. In the cross-sections, the cavities shown with transmission electron microscopy were also found.[8],[9]

The term TTH is a descriptive clinical term of little scientific rigor. This disorder has been reported mainly as pili annulati; however, rings are not observed. In analogy to pili canaliculi (also known as pili trianguli et canaliculi), clinically characterized by “uncombable hairs,” in which well-formed grooving is observed in the SEM,[13] we suggest the term pili microcanaliculi to describe this condition, based in the ultrastructural findings of the hair surface.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Murugusundram S. Spangled hair in siblings. Int J Trichology 2009;1:35-6.  Back to cited text no. 1
    
2.
Theodosiou G, Hamnerius N, Svensson Å. Banded scalp hair with an unusual glistening appearance in a teenager: A quiz. Acta Derm Venereol 2018;98:473-4.  Back to cited text no. 2
    
3.
Giehl KA, Dean D, Dawber RP, Leigh I, de Berker DA, Wojnarowska F. Cytokeratin expression in pili annulati hair follicles. Clin Exp Dermatol 2005;30:426-8.  Back to cited text no. 3
    
4.
Akoglu G, Emre S, Metin A, Erbil KM, Akpolat D, Firat A, et al. Pili annulati with fragility: Electron microscopic findings of a case. Int J Trichology 2012;4:89-92.  Back to cited text no. 4
    
5.
Bhoyrul B, Lindsay H, Robinson R, Stahlschmidt J, Palmer T, Edward S, et al. Pili annulati in a case of Rothmund-Thomson syndrome with a novel frameshift mutation in RECQL4. J Eur Acad Dermatol Venereol 2018;32:e221-3.  Back to cited text no. 5
    
6.
Tosti A, Berker DA, Giehl KA, Eckstein ÃG, Benet-Page A, Strom TM, et al. A gene locus responsible for the familial hair shaft abnormality pili annulati maps to chromosome 12q24.32-24.33. J Invest Dermatol 2004;123:1073-7.  Back to cited text no. 6
    
7.
Moffitt DL, Lear JT, de Berker DA, Peachey RD. Pili annulati coincident with alopecia areata. Pediatr Dermatol 1998;15:271-3.  Back to cited text no. 7
    
8.
Giehl KA, Ferguson DJ, Dawber RP, Pittelkow MR, Foehles J, de Berker DA. Update on detection, morphology and fragility in pili annulati in three kindreds. J Eur Acad Dermatol Venereol 2004;18:654-8.  Back to cited text no. 8
    
9.
Ito M, Hashimoto K, Sakamoto F, Sato Y, Voorhees JJ. Pathogenesis of pili annulati. Arch Dermatol Res 1988;280:308-18.  Back to cited text no. 9
    
10.
Castelli E, Fiorella S, Caputo V. Pili annulati coincident with alopecia areata, autoimmune thyroid disease, and primary IgA deficiency: Case report and considerations on the literature. Case Rep Dermatol 2012;4:250-5.  Back to cited text no. 10
    
11.
Utiyama Y, Rosa IP, Eid CA, Mello Filho A. Pili annulati – A case report. An Bras Dermatol 1983;5:227-8.  Back to cited text no. 11
    
12.
Gonzalez AM, Borda LJ, Tosti A. Pili annulati with severe trichorrhexis nodosa: A case report and review of the literature. Skin Appendage Disord 2019;5:114-6.  Back to cited text no. 12
    
13.
de Almeida HL Jr., da Cunha Filho RR, de Castro LA, Rocha NM, Abrantes V. Microscopic aspects of pili canaliculi. J Eur Acad Dermatol Venereol 2007;21:139-40.  Back to cited text no. 13
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

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