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Anais Brasileiros de Dermatologia

Print version ISSN 0365-0596

An. Bras. Dermatol. vol.85 no.5 Rio de Janeiro Sept./Oct. 2010 



Dermoscopic clues to distinguish trichotillomania from patchy alopecia areata*



Leonardo Spagnol AbrahamI; Fernanda Nogueira TorresII; Luna Azulay-AbulafiaIII

ISpecialist in Dermatology, Dermatologist, Institute of Dermatology and Esthetics, Rio de Janeiro (IDERJ). Currently participating in a Master's Degree Program at the Department of Anatomopathology of the Federal University of Rio de Janeiro (UFRJ). Preceptor of the Alopecia and Dermatoscopy Clinic, Professor Rubem David Azulay Institute of Dermatology, Rio de Janeiro, Brazil
IISpecialist in Dermatology. Dermatologist, Institute of Dermatology and Esthetics, Rio de Janeiro (IDERJ), Rio de Janeiro, Brazil
IIIMasters and Doctorate degrees awarded by the Federal University of Rio de Janeiro (UFRJ). Dermatologist, Institute of Dermatology and Esthetics, Rio de Janeiro (IDERJ). Professor of the Postgraduate Course at the Professor Rubem David Azulay Institute of Dermatology, Rio de Janeiro, Brazil, and at the State University of Rio de Janeiro (UERJ). Adjunct Professor at the State University of Rio de Janeiro (UERJ). Professor at the Gama Filho University (UGF), Rio de Janeiro, Brazil

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BACKGROUND: Trichotillomania and patchy alopecia areata have similar clinical and dermoscopic features.
OBSERVATIONS: In trichotillomania, dermoscopy shows decreased hair density, short vellus hair, broken hairs with different shaft lengths, coiled hairs, short vellus hair, trichoptilosis, sparse yellow dots, which may or may not contain black dots and no exclamation mark hairs.
CONCLUSIONS: In the case of patchy alopecia and broken hairs, the absence of exclamation mark hairs suggests a diagnosis of trichotillomania. On the other hand, the finding of yellow dots without black dots does not exclude it.

Keywords: Alopecia; Anxiety disorders; Dermoscopy; Differential Diagnosis; Nail biting




Trichotillomania is a compulsive disorder characterized by the patient's habit of pulling out his/her own hair, generally from the parietal and vertex regions. 1 The disorder most often affects female children and adolescents, who generally deny the habit.

This condition resembles alopecia areata (AA), since both disorders are initially non-scarring and may be patchy. At dermoscopy, characteristics that are common to both conditions include the presence of short vellus hairs, dystrophic hair and black and yellow dots. 2 A key diagnostic finding in patients with AA that is considered pathognomonic by some authors is exclamation mark hair. 2,3

Considering that prognoses and treatment are different in trichotillomania and AA, it would be useful to be able to establish these differences using noninvasive methods such as dermoscopy, since histopathology may be inconclusive and the biopsy procedure traumatic, particularly in children.

With respect to the dermoscopic characteristics of these conditions, little has been published on trichotillomania, 4-6 the majority of articles referring to AA.2,3,6-8



Examination of the scalp of patients with trichotillomania generally reveals asymmetrical patches of alopecia, particularly in the frontal and vertex regions. Hairs of varying lengths and short vellus hairs may be seen in these patches (Figure 1). The hair pull test is negative along the edges.



Other compulsive disorders such as onychophagia and onychotillomania, for example, may be present in patients with trichotillomania.

In AA, the clinical condition is characterized by smooth, round or oval patches of non-scarring alopecia, with the hair pull test strongly positive along the edges of these patches, particularly those in activity. Examination of the patient's nails may reveal pitting (Table 1).9

In cases of trichotillomania, dermoscopy reveals abnormalities resulting from the stretching and fracture of hair shafts. Fracture may occur at varying lengths, resulting in black dots, hair broken off, either close to the hair follicles or at different distances from them, fraying hair, longitudinally split hair, coiled hair and stretching of the shaft. Other dermoscopic findings include decreased hair density, empty follicular ostia and some yellow dots that may or may not contain black dots (Figure 2). Areas with signs of scratching and bleeding may also be found.



In AA, dermoscopy characteristically shows exclamation mark hairs, particularly along the edges of the patches where the activity of the disease is greater. Other dystrophic hairs formed by alterations in the hair cycle due to the inflammatory process may also be seen, including black dots or cadaverized hair, kinking hair and pseudo-monilethrix characterized by constrictions in the shaft resulting from periods of inflammatory activity in the hair follicle (Figure 3).

Short vellus hair is seen in both trichotillomania and AA; however, in AA, hairs may be white (Table 2).



Both trichotillomania and AA predominantly affect children. Establishing clinical and dermoscopic patterns is a useful way of avoiding having to perform biopsies in this young age group, with the additional complication that histopathology may be inconclusive. Onychophagia and onychotillomania may be present together with other symptoms of anxiety and may constitute part of the obsessive-compulsive disorder of the patient with trichotillomania.

AA generally presents as round or oval patches of alopecia, whereas in trichotillomania patches tend to be asymmetrical, geometrical or in unusual patterns; however, round patches may also be present in trichotillomania, making differentiation difficult. 5

The hair pull test is a useful semiotic element, which, if negative, favors a diagnosis of trichotillomania. 5 In AA, it is positive, particularly along the edges of patches in activity. 9

In cases of AA, dermoscopic findings include clusters of short vellus hairs (shorter than 10 mm), as well as yellow dots and dystrophic hair (black dots or cadaverized hair) and exclamation mark hair. 2,3

Ross et al. were the first to observe yellow dots in a patient with trichotillomania; however, biopsy revealed AA in the same patch. 3 In the studies conducted by Inui et al., a few yellow dots were found in cases of androgenetic alopecia and in trichotillomania. These authors suggest that in trichotillomania all the yellow dots should contain the black dots that constitute the remains of the dead hair follicles, which would differentiate this condition from AA. 2 Nevertheless, yellow dots without black dots may be present albeit to a lesser extent. 2

The presence of black dots, coiled hair, shafts of varying lengths with fraying or split ends (trichoptilosis) and an absence of exclamation mark hairs is suggestive of trichotillomania. In accordance with the literature, this finding is considered pathognomonic of AA. 2,3

The hairs with fraying ends that are seen in trichotillomania may resemble exclamation mark hairs (Figure 2A), hampering differentiation between the two conditions, particularly when both trichotillomania and AA are present.



Dermoscopy has proved to represent a useful tool for differentiating between trichotillomania and patchy AA, thus avoiding scalp biopsy, which is particularly important in the case of children. Fractured shafts are suggestive of trichotillomania, while the presence of exclamation mark hairs is indicative of AA. In cases of trichotillomania, dermoscopy may also reveal some yellow dots, not necessarily containing remnants of dead hair follicles (black dots).



1. Bartels NG, Blume-Peytavi U. Hair loss in children. In: Blume-Peytavi U, Tosti A, Whiting D, Trüeb R, editors. Hair Growth and Disorders. Leipzig: Springer; 2008. p. 293-4.         [ Links ]

2. Inui S, Nakajima T, Nakagawa K, Itami S. Clinical significance of dermoscopy in alopecia areata: analysis of 300 cases. Int J Dermatol. 2008;47:688-93.         [ Links ]

3. Ross EK, Vincenzi C, Tosti A. Videodermoscopy in the evaluation of hair and scalp disorders. J Am AcadDermatol. 2006;55:799-806.         [ Links ]

4. Lee DY, Lee JH, Yang JM, Lee ES. The use of dermoscopy for the diagnosis of trichotillomania. J Eur Acad Dermatol Venereol. 2009;23:731-2.         [ Links ]

5. Pereira JM. Compulsive trichoses. An Bras Dermatol. 2004;79:609-18.         [ Links ]

6. Rakowska A, Slowinska M, Kowalska-Oledzka E, Olszewska M, Czuwara J, Rudnicka L. Alopecia areata incognita: true or false? J Am Acad Dermatol. 2009;60:162-3.         [ Links ]

7. Tosti A, Whiting D, Iorizzo M, Pazzaglia M, Misciali C, Vincenzi C, et al. The role of scalp dermoscopy in the diagnosis of alopecia areata incognita. J Am Acad Dermatol. 2008;59:64-7.         [ Links ]

8. Inui S, Nakajima T, Itami S. Dry dermoscopy in clinical treatment of alopecia areata. J Dermatol. 2007;34:635-9.         [ Links ]

9. Rivitti EA. Alopecia areata: revisão e atualização. An Bras Dermatol. 2005;80:57-68.         [ Links ]



Mailing address:
Leonardo Spagnol Abraham
Instituto de Dermatologia e Estética do Rio de Janeiro (IDERJ)
R. Alexandre Ferreira, 206 - Lagoa
22470 220 Rio de Janeiro - RJ, Brazil
Tel.: +55 21 9218-4164 / 2537-2108 Fax: +55 21 2537-2108

Received on 05.04.2010.
Approved by the Advisory Board and accepted for publication on 29.04.10.
Conflict of interest: None
Financial funding: None



* Study conducted at Institute of Dermatology and Esthetics, Rio de Janeiro (IDERJ), Rio de Janeiro, Brazil.

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