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 Table of Contents  
EDITORIAL
Year : 2018  |  Volume : 5  |  Issue : 2  |  Page : 73-77

Lichen planus pigmentosus and frontal fibrosing alopecia: The link explored


Department of Dermatology, Venereology and Leprology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Date of Web Publication14-Dec-2018

Correspondence Address:
Dr. Muthu Sendhil Kumaran
Department of Dermatology, Venereology and Leprology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/Pigmentinternational.Pigmentinternational_

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  Abstract 


There has been a recent rush of data regarding the combined presentation of lichen planus pigmentosus and frontal fibrosing alopecia in premenoposal women of dark skin. This review article addresses the relationship between the two.

Keywords: Acquired dermal macular hyperpigmentation, frontal fibrosing alopecia, lichen planus pigmentosus


How to cite this article:
Raihan A, Kumaran MS. Lichen planus pigmentosus and frontal fibrosing alopecia: The link explored. Pigment Int 2018;5:73-7

How to cite this URL:
Raihan A, Kumaran MS. Lichen planus pigmentosus and frontal fibrosing alopecia: The link explored. Pigment Int [serial online] 2018 [cited 2019 Jul 18];5:73-7. Available from: http://www.pigmentinternational.com/text.asp?2018/5/2/73/247504




  Introduction Top


Lichen planus pigmentosus (LPP) is a pigmented macular variant of lichen planus, described for the first time by Bhutani et al.[1] from India in 1974. It is characterized by asymptomatic dark brown macules distributed principally over photo-exposed sites in dark skinned individuals.

Frontal fibrosing alopecia (FFA), on the other hand, is a primary lymphocytic scarring alopecia that presents with a typical clinical pattern of progressive frontotemporal hairline recession and eyebrow loss. Initially described in 1994 by Kossard,[2] it is considered as a clinical variant of lichen planopilaris, predominantly affecting postmenopausal women,[3] although premenopausal women and men may also be affected.

Dlova[4] described the co-occurrence of these two conditions, for first time in 24 cases from Durban; however, similar reports are now available from all over globe.

Epidemiology

LPP is essentially a disease of adulthood, occurring after 30 years of age in predominantly dark skinned individuals. Cases of LPP have been reported from India, Africa, Korea, Japan, the Middle East, and Latin America.

The onset of FFA is described predominantly in postmenopausal women (80%–85%) between the ages of 55 and 70 years.[3] About 80% to 90% of all FFA patients are Caucasian, whereas the remaining patients are Asian, African, Hispanic, or East Indian.[5],[6] However, Dlova et al. reported the combination of FFA and LPP to occur more frequently in younger, premenopausal women with the age range of 25 to 56 years, among African population. This she explained on the basis of hair grooming techniques among the said population.[4] These findings are in contrast to those of Pirmez et al.[7] and Romiti et al.,[8] in whose studies, only 17% and 27%, respectively, were premenopausal.

Pathogenesis

The exact pathogenesis of either disease as well as their coexistence is elusive. A variety of agents have been suggested as predisposing factors for the development of LPP, the most important of which is sunlight.[9] The development of lesions in sun-exposed areas in most patients supports this hypothesis. Other possible contributors include hepatitis C virus; allylthiocynate—a potential photosensitizer in mustard oil; amla oil; cosmetics such as hair dye, fragrances, kumkum (a red pigment used by Indian women on their foreheads), and gold therapy.[10],[11],[12] T-cell abnormalities have also been implicated.[10] What is interesting to note is that several of these agents have also been implicated in conditions such as Reihl’s melanosis and ashy dermatosis, and their clinical features often overlap, making differentiation difficult. An umbrella term “Acquired Dermal Macular Hyperpigmentation (ADMH)” has been proposed to avoid controversies and includes these three conditions.[13]

FFA is postulated to develop after an interplay of hormonal, genetic, and environmental factors. Hormonal changes, such as changing estrogen levels in perimenopausal women, may trigger an inflammatory scarring process.[14],[15] Indeed, some studies have demonstrated a history of early menopause in a significant number of women with FFA. However, with recent reports showing the occurrence of FFA in premenopausal women, factors other than hormones need to be looked at. There have also been reports of FFA occurring in a familial pattern. Other possible contributors are environmental factors and personal care.

The sequential progression from LPP to FFA in most patients indicates that LPP and FFA are parts of the same spectrum of disease. The recession of frontotemporal hairline and co-localization of pigmentation suggest a probable role of contact allergy due to hair dye or facial cosmetics in pathogenesis of both conditions. A probable explanation is that the lesser density of hair in the anterior aspect of scalp, as well as contact with a larger amount of hair dye product with the initial stroke of application, results in preferential involvement of anterior hairline through contact allergy as well as photosensitization.[16] Similarly, positive photopatch test to paraphenylenediamine and other cosmetics has been seen among ADMH patients.[17],[18]

Recent studies have highlighted the possible role of sunscreens as well as ultraviolet (UV) filters in hair care and skin care products that are added to prevent discoloration/photodegradation of the product in storage. These were found to contain many chemicals including benzophenone 4, benzyl salicylate (which is also used as a fragrance), and ethylhexyl methoxycinnamate, that are suspected to give rise to FFA.[19],[20] Hence, a patient with LPP, who is advised the use of sunscreens and depigmenting agents, may be predisposed to develop FFA. Further studies are required to validate this theory.

The increased number of Langerhans cells in histopathology specimens of FFA also supports the theory of contact sensitization in its causation.[21] Peroxisome proliferator-activated receptor (PPAR-gamma) has been implicated to play a crucial role in the pathogenesis of the two entities occurring together. PPAR-gamma is important in the process of melanocyte proliferation, and its deficiency affects melanocyte-dependent free-radical scavenging in hair follicles.[22] This effect is especially enhanced in a preexisting background of inflammation due to LPP. Moreover, PPAR-gamma regulates Melanocyte-inducing transcription factor (MITF) signaling which is involved in the process of melanogenesis as well as anagen hair cycle.[23]

Clinical features

LPP is characterized by the onset of “slate gray to brownish-black macules” that present in sun-exposed areas and flexural folds. The pigmentation may be diffuse, blotchy and reticular, or perifollicular, but the diffuse form is most frequent.[10] Cutaneous/oral Lichen planus (LP) may coexist in a subset of patients. The lesions first appear on face and neck, spreading gradually to involve the upper limbs and trunk.

FFA is characterized by progressive and symmetrical band of hair loss in the frontal or frontotemporal hairline. Perifollicular erythema may be seen in the hair left behind. The affected area is often uniformly “pale with loss of follicular ostia.”[24] Disease progression is variable and ranges from 0.6 to 1.1-cm recession per year.[14],[15],[25] Occipital involvement may be seen in 7% to 15% of patients.[14],[25] Pruritus may be present and may be the presenting complaint. Eyebrows may be affected in 40% to 95% of patients. Loss of eyelash is uncommon.[6],[15],[25] FFA has been recently classified[26] into three patterns, namely, linear pattern, diffuse pattern, double-line or pseudo fringe pattern. Other peculiar patterns include Androgenetic alopecia (AGA-like), cockade-like, and ophiasis-like patterns. The “lonely hair” sign (isolated terminal hair follicles are seen remotely from the receding hairline), pseudo “fringe sign” and “doll hairline” are clinical clues to this condition. Severity can be graded from I to V based on recession from anterior hairline [Table 1].[15]
Table 1: Grading of FFA severity based on distance of hair loss from anterior hairline; as given by Vano-Galvan et al.[15]

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Romiti et al.[8] found 17% of patients of FFA to have concomitant LPP, in contrast to 55% described by Dlova.[4] Among the cases reported so far, majority developed LPP followed by the occurrence of FFA. The mean time lag between the development of LPP and FFA was 14 months (range 6–36 months).[4],[8],[16],[27] Frontotemporal hair loss with eyebrow loss was present in almost all patients with other site body hair loss and facial papules in a minority. All patients presented with facial hyperpigmentation with or without other site involvement except for a single case reported by Franco-Munoz et al.,[28] wherein FFA was followed by reticular LPP over submental area, neck, and upper chest. Most frequent was a diffuse pattern followed by reticulated and isolated pigmented macules[4],[7],[8],[16],[29] [[Figure 1]A and B].
Figure 1: (A and B) Clinical picture of a patient with coexisting FFA and LPP: diffuse pattern hyperpigmentation on face with recession of anterior hairline and loss of eyebrows. (C) Histopathology of FFA showing perifollicular lichenoid infiltrate with evidence of concentric fibrosis around the hair follicle. H&E, ×100

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  Investigations Top


Histopathology

Skin biopsy in LPP shows an interface dermatitis pattern in the form of basal cell vacuolar degeneration, keratinocyte apoptosis, and pigment incontinence, which may involve hair follicles and eccrine glands. Hyperkeratosis, epidermal atrophy, and dermal infiltrates are other features of LPP.[10] According to Al-Mutairi and El-Khalawany, the location of dermal infiltrates varies with the age of the lesions. The newer lesions show a band-like infiltrate, whereas the older lesions frequently have a perivascular infiltrate instead.[30] IgG, IgM, and C3 deposits have all been reported on DIF.[10],[30]

Biopsy specimens of FFA shows lymphocytic infiltrate in the perifollicular area with varying degrees of scarring and loss of hair follicles[14],[31] [[Figure 1]C].

Romiti et al., in nine cases of LPP with FFA, noted epidermal atrophy with vacuolar basal cell degeneration in 78% of patients. Basal membrane thickening (50%), interfollicular inflammatory infiltrates (66.6%), and interfollicular melanophages (100%) were other findings among these cases. Perifollicular changes were found in all cases including melanophages (100%), inflammatory infiltrates (42.8%), lichenoid infiltrates (25%), follicular basal cell vacuolar changes (57%), and basal membrane thickening (25%). This study further reported interface dermatitis-like changes on sweat duct and lichenoid perisebaceitis.[8]

Dermoscopy

Pirmez et al. studied the dermoscopic features of LPP lesions in patients with both LPP and FFA and described various patterns, including “pseudonetwork pattern,” “blue-gray dots arranged in circles,” “speckled blue-gray dots,” “dotted pattern,” “rhomboids and asymmetric pigmented follicular openings,” “focal and diffuse erythema,” telangiectatic vessels, and loss of facial vellus hairs. The “dotted pattern” and circles corresponded to eccrine and follicular involvement, respectively, on histopathological correlation.[7] Vinay et al.[13] have proposed a severity score for ADMH on the basis of dermoscopic features [Table 2].
Table 2: Dermoscopic grading of ADMH as given by Vinay et al.

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Another recent study by Kumaran et al. studying cases of ADMH with and without FFA, found similar findings: dotted pattern (owl’s eye/targetoid structure) (36.8%), periappendageal accentuation of pigment structures (78.9%), blue-gray dots/Chinese letter pattern (52.6%), reticular/diffuse pattern (68.4%), perifollicular white halo (26.3%), telengiectasia (26.3%), and loss of vellus hairs (21.1%) on trichoscopy. Trichoscopic features of FFA lesions showed perifollicular white halo, perifollicular erythema and scaling, empty hair follicles, lone hairs, scarred white areas, and pigment structures surrounding black hairs.

The observation of pigmented structures more around remaining black hairs was a newer finding in this study. The authors explained this finding hypothesizing that the remaining pigmented hair continuously replenishes the lost basal cell melanocytes in ADMH.[16]

Differential diagnosis

LPP needs to be differentiated from other causes of ADMH, which includes pigmented contact dermatitis/Reihl’s melanosis, ashy dermatosis, ochronosis, and melasma. FFA, on the other hand, needs to be differentiated from lichen planopilaris, traction alopecia, and alopecia areata.

Dermoscopic findings can help distinguish FFA from traction alopecia (white dots, broken, and miniaturized hairs), lichen planopilaris (perifollicular erythema, perifollicular scaling, and loss of follicular ostia), and alopecia areata (yellow and black dots, dystrophic hairs, and exclamation mark hairs).[32]

Treatment

Most treatments for both conditions are unsatisfactory and only halt progression of disease activity. There is lack of good-quality evidence to standardize treatment regimens and outcome measures. Several authors have reported improvement or stabilization of FFA with topical, intralesional, and systemic corticosteroids,[2],[5],[33],[34],[35],[36] topical minoxidil,[2],[14] antibiotics,[6] hydroxychloroquine,[6],[15],[25],[35] topical and oral immunomodulators, tacrolimus,[25] and 5-alpha-reductase inhibitors.[15] Combination therapy appears to be the standard for FFA. Options for treatment of LPP include topical and systemic steroids,[37],[38] topical tacrolimus,[30],[37] dapsone,[37],[39] vitamin A,[40] retinoids,[38] azelaic acid, kojic acid, glycolic acid, and pigment laser[41],[42],[43] along with photoprotection.

Prognosis

Data on the natural history of either disease is lacking in literature; however, it is known that both FFA and LPP do stabilize in due time. As to the extent and duration of stabilization, it is still a blur. Symptomatic lesions, longer duration, severe dermoscopic grades, “dotted pattern” on dermoscopy, and a prominent perifollicular involvement in the patients of ADMH are proposed clues to the development of FFA in the long run.[16]


  Conclusion Top


The co-occurrence of LPP and FFA implies they are but two entities belonging to the same spectrum of disease. Both entities by themselves cause significant morbidity among patients. There is a need for further well-structured studies to find the missing links as well as to come up with suitable effective treatment regimens for these conditions. Considering the irreversible nature of scarring alopecia, a watchful eye on all patients of LPP for the development of FFA, with the use of dermoscopy, where available, could go a long way in improving the quality of life in these patients.

ACKNOWLEDGMENT

Authors would like to thank Dr. Razmi T., MD, DNB, MNAMS, for his help in research and for the clinical pictures.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Bhutani LK, Bedi TR, Pandhi RK, Nayak NC. Lichen planus pigmentosus. Dermatologica 1974;149:43-50.  Back to cited text no. 1
    
2.
Kossard S. Postmenopausal frontal fibrosing alopecia. Scarring alopecia in a pattern distribution. Arch Dermatol 1994;130:770-4.  Back to cited text no. 2
    
3.
Miteva M, Whiting D, Harries M, Bernardes A, Tosti A. Frontal fibrosing alopecia in black patients. Br J Dermatol 2012;167:208-10.  Back to cited text no. 3
    
4.
Dlova NC. Frontal fibrosing alopecia and lichen planus pigmentosus: Is there a link? Br J Dermatol 2013;168:439-42.  Back to cited text no. 4
    
5.
Banka N, Mubki T, Bunagan MJ, McElwee K, Shapiro J. Frontal fibrosing alopecia: A retrospective clinical review of 62 patients with treatment outcome and long-term follow-up. Int J Dermatol 2014;53:1324-30.  Back to cited text no. 5
    
6.
Samrao A, Chew AL, Price V. Frontal fibrosing alopecia: A clinical review of 36 patients. Br J Dermatol 2010;163:1296-300.  Back to cited text no. 6
    
7.
Pirmez R, Duque-Estrada B, Donati A, Campos-do-Carmo G, Valente NS, Romiti R et al. Clinical and dermoscopic features of lichen planus pigmentosus in 37 patients with frontal fibrosing alopecia. Br J Dermatol 2016;175:1387-90.  Back to cited text no. 7
    
8.
Romiti R, Biancardi Gavioli CF, Anzai A, Munck A, Costa Fechine CO, Valente NYS. Clinical and histopathological findings of frontal fibrosing alopecia-associated lichen planus pigmentosus. Skin Appendage Disord 2017;3:59-63.  Back to cited text no. 8
    
9.
Rieder E, Kaplan J, Kamino H, Sanchez M, Pomeranz MK. Lichen planus pigmentosus. Dermatol Online J 2013;19:20713.  Back to cited text no. 9
    
10.
Kanwar AJ, Dogra S, Handa S, Parsad D, Radotra BD. A study of 124 Indian patients with lichen planus pigmentosus. Clin Exp Dermatol 2003;28:481-5.  Back to cited text no. 10
    
11.
Vachiramon V, Suchonwanit P, Thadanipon K. Bilateral linear lichen planus pigmentosus associated with hepatitis C virus infection. Case Rep Dermatol 2010;2:169-72.  Back to cited text no. 11
    
12.
Gupta D, Thappa DM. Dermatoses due to Indian cultural practices. Indian J Dermatol 2015;60:3-12.  Back to cited text no. 12
[PUBMED]  [Full text]  
13.
Vinay K, Bishnoi A, Parsad D, Saikia UN, Sendhil Kumaran M. Dermatoscopic evaluation and histopathological correlation of acquired dermal macular hyperpigmentation. Int J Dermatol 2017;56:1395-9.  Back to cited text no. 13
    
14.
Tosti A, Piraccini BM, Iorizzo M, Misciali C. Frontal fibrosing alopecia in postmenopausal women. J Am Acad Dermatol 2005;52:55-60.  Back to cited text no. 14
    
15.
Vano-Galvan S, Molina-Ruiz AM, Serrano-Falcon C, Arias-Santiago S, Rodrigues-Barata AR, Garnacho-Saucedo G et al. Frontal fibrosing alopecia: A multicenter review of 355 patients. J Am Acad Dermatol 2014;70:670-8.  Back to cited text no. 15
    
16.
Kumaran MS, Razmi TM, Vinay K, Parsad D. Clinical, dermoscopic, and trichoscopic analysis of frontal fibrosing alopecia associated with acquired dermal macular hyperpigmentation: A cross sectional observational case–control study. J Am Acad Dermatol 2018;79:588-91.  Back to cited text no. 16
    
17.
Garg T, Agarwal S, Chander R, Singh A, Yadav P. Patch testing in patients with suspected cosmetic dermatitis: A retrospective study. J Cosmet Dermatol 2018;17:95-100.  Back to cited text no. 17
    
18.
Tienthavorn T, Tresukosol P, Sudtikoonaseth P. Patch testing and histopathology inThai patients with hyperpigmentation due to erythema dyschromicum perstans, lichen planus pigmentosus, and pigmented contact dermatitis. Asian Pac J Allergy Immunol 2014;32:185-92.  Back to cited text no. 18
    
19.
Callander J, Frost J, Stone N. Ultraviolet filters in hair-care products: A possible link with frontal fibrosing alopecia and lichen planopilaris. Clin Exp Dermatol 2018;43:69-70.  Back to cited text no. 19
    
20.
Aldoori N, Dobson K, Holden CR, McDonagh AJ, Harries M, Messenger AG. Frontal fibrosing alopecia: Possible association with leave-on facial skin care products and sunscreens; a questionnaire study. Br J Dermatol 2016;175:762-7.  Back to cited text no. 20
    
21.
Ma SA, Imadojemu S, Beer K, Seykora JT. Inflammatory features of frontal fibrosing alopecia. J Cutan Pathol 2017;44:672-6.  Back to cited text no. 21
    
22.
Ramot Y, Mastrofrancesco A, Camera E, Desreumaux P, Paus R, Picardo M. The role of PPARgamma-mediated signalling in skin biology and pathology: New targets and opportunities for clinical dermatology. Exp Dermatol 2015;24:245-51.  Back to cited text no. 22
    
23.
Schneider MR, Schmidt-Ullrich R, Paus R. The hair follicle as a dynamic miniorgan. Curr Biol 2009;19:R132-42.  Back to cited text no. 23
    
24.
Camacho Martinez F, Garcia-Hernandez MJ, Mazuecos Blanca J. Postmenopausal frontal fibrosing alopecia. Br J Dermatol 1999;140:1181-2.  Back to cited text no. 24
    
25.
MacDonald A, Clark C, Holmes S. Frontal fibrosing alopecia: A review of 60 cases. J Am Acad Dermatol 2012;67:955-61.  Back to cited text no. 25
    
26.
Moreno-Arrones OM, Saceda-Corralo D, Fonda-Pascual P, Rodrigues-Barata AR, Buendia-Castano D, Alegre-Sanchez A et al. Frontal fibrosing alopecia: Clinical and prognostic classification. J Eur Acad Dermatol Venereol 2017;31:1739-45.  Back to cited text no. 26
    
27.
Mulinari-Brenner FA, Guilherme MR, Peretti MC, Werner B. Frontal fibrosing alopecia and lichen planus pigmentosus: Diagnosis and therapeutic challenge. An Bras Dermatol 2017;92(5 Suppl 1):79-81.  Back to cited text no. 27
    
28.
Franco-Munoz M, Garcia-Arpa M, Lozano-Masdemont B, Ramos-Rodriguez C. Frontal fibrosing alopecia and extrafacial lichen planus pigmentosum in a caucasian woman. An Bras Dermatol 2017;92(5 Suppl 1):76-8.  Back to cited text no. 28
    
29.
Berliner JG, McCalmont TH, Price VH, Berger TG. Frontal fibrosing alopecia and lichen planus pigmentosus. J Am Acad Dermatol 2014;71:e26-7.  Back to cited text no. 29
    
30.
Al-Mutairi N, El-Khalawany M. Clinicopathological characteristics of lichen planus pigmentosus and its response to tacrolimus ointment: An open label, non-randomized, prospective study. J Eur Acad Dermatol Venereol 2010;24:535-40.  Back to cited text no. 30
    
31.
Poblet E, Jimenez F, Pascual A, Pique E. Frontal fibrosing alopecia versus lichen planopilaris: A clinicopathological study. Int J Dermatol 2006;45:375-80.  Back to cited text no. 31
    
32.
Rubegni P, Mandato F, Fimiani M. Frontal fibrosing alopecia: Role of dermoscopy in differential diagnosis. Case Rep Dermatol 2010;2:40-5.  Back to cited text no. 32
    
33.
Naz E, Vidaurrazaga C, Hernandez-Cano N, Herranz P, Mayor M, Hervella M et al. Postmenopausal frontal fibrosing alopecia. Clin Exp Dermatol 2003;28:25-7.  Back to cited text no. 33
    
34.
Vaisse V, Matard B, Assouly P, Jouannique C, Reygagne P. Postmenopausal frontal fibrosing alopecia: 20 Cases. Ann Dermatol Venereol 2003;130:607-10.  Back to cited text no. 34
    
35.
Moreno-Ramirez D, Camacho Martinez F. Frontal fibrosing alopecia: A survey in 16 patients. J Eur Acad Dermatol Venereol 2005;19:700-5.  Back to cited text no. 35
    
36.
Tan KT, Messenger AG. Frontal fibrosing alopecia: Clinical presentations and prognosis. Br J Dermatol 2009;160:75-9.  Back to cited text no. 36
    
37.
Sehgal VN, Verma P, Bhattacharya SN, Sharma S, Rasool F. Lichen planus pigmentosus. Skinmed 2013;11:96-103.  Back to cited text no. 37
    
38.
Dabas G, Vinay K, Parsad D, Chatterjee D, Kumaran MS. A retrospective study of lichen planus pigmentosus with focus on palmoplantar involvement. Clin Exp Dermatol 2018. [Epub ahead of print]. doi: 10.1111/ced.13696  Back to cited text no. 38
    
39.
Verma P, Pandhi D. Topical tacrolimus and oral dapsone combination regimen in lichen planus pigmentosus. Skinmed 2015;13:351-4.  Back to cited text no. 39
    
40.
Bhutani LK, George M, Bhate SM. Vitamin A in the treatment of lichen planus pigmentosus. Br J Dermatol 1979;100:473-4.  Back to cited text no. 40
    
41.
Han XD, Goh CL. A case of lichen planus pigmentosus that was recalcitrant to topical treatment responding to pigment laser treatment. Dermatol Ther 2014;27:264-7.  Back to cited text no. 41
    
42.
Kim JE, Won CH, Chang S, Lee MW, Choi JH, Moon KC. Linear lichen planus pigmentosus of the forehead treated by neodymium:yttrium-aluminum-garnet laser and topical tacrolimus. J Dermatol 2012;39:189-91.  Back to cited text no. 42
    
43.
Shah DSD, Aurangabadkar DS, Nikam DB. An open-label nonrandomized prospective pilot study of the efficacy of Q-switched Nd-YAG laser in management of facial lichen planus pigmentosus. J Cosmet Laser Ther 2018:1-8. [Epub ahead of print]. doi: 10.1080/14764172.2018.1469770  Back to cited text no. 43
    


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    Tables

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