Primary cicatricial alopecias (PCA) are a heterogeneous group of inflammatory disorders in which the hair follicle is the primary target of destruction. The North American Hair Research Society (NAHRS) classification groups them as lymphocytic, neutrophilic or mixed according to the dominant perifollicular infiltrate [1]. Damage to the follicular bulge stem-cell compartment, followed by replacement with fibrous tissue, makes hair loss permanent [2]. In a multicentre study of 22 specialist hair clinics, cicatricial alopecias formed 27% of alopecia diagnoses, and frontal fibrosing alopecia (FFA) was the most frequent cicatricial type [3]. Diagnosis is difficult because clinical and histological features overlap, and in end-stage disease the inflammatory infiltrate may be minimal or absent on routine H&E sections [4,5]. Trichoscopy is a non-invasive tool whose validity in PCA has been evaluated [6], and it can help select the biopsy site. Elastic tissue staining (VVG) highlights patterns of perifollicular fibrosis that may add diagnostic information when H&E is non-diagnostic [4,5]. Indian series have described the clinical, trichoscopic and histopathological profile of PCA [7,8], but few have examined lesional and perilesional trichoscopy together with histopathology and VVG staining in the same patients. We therefore studied the clinicoepidemiological, trichoscopic and histopathological features of PCA at a tertiary care centre in Mumbai, and correlated trichoscopic findings with histopathology and VVG pattern.

Study design and setting. This was a single-centre, descriptive, cross-sectional, observational study conducted over 18 months in the Department of Dermatology, Venereology and Leprology, Seth G. S. Medical college and KEM Hospital, Parel, Mumbai. The study is reported according to the STROBE statement. Participants and sample size. Patients of any age and either sex with primary cicatricial alopecia who gave consent were enrolled by convenience sampling. Patients with secondary cicatricial alopecia and those who did not consent were excluded. The minimum sample size, calculated as n = 4pq/d2 with an assumed PCA prevalence of 3% and allowable error of 5%, was 50 [sample size reconciliation: 69 patients were enrolled and analysed]. Clinical evaluation. A detailed history (age, sex, occupation, symptoms and duration, aggravating and relieving factors, hair-product or topical application, comorbidities, drug and family history) and cutaneous and systemic examination were recorded on a case record form. Clinical photographs were taken after written informed consent. Investigations were done only where clinically indicated. Trichoscopy. Lesional and perilesional (within 2 cm of the active margin) sites were examined with a Dino-Lite video dermatoscope at x40 magnification under white and polarised light, and images were archived. Thirteen trichoscopic features were recorded. Histopathology and VVG staining. One trichoscopy-guided punch biopsy was taken from the active lesional edge, where present. Sections were stained with H&E, and twelve histopathological parameters were assessed. VVG elastic staining was done on a subset of biopsies to classify perifollicular fibrosis as wedge-shaped or broad tree-trunk-shaped. Statistical analysis. Data were analysed with IBM SPSS Statistics version 22.0. Continuous variables are given as mean +/- SD (and median where reported) and categorical variables as frequencies and percentages. LPP and DLE were compared using the chi-square test (Yates-corrected) or Fisher's exact test (expected cell count < 5), and the Mann-Whitney U test for age; the Kruskal-Wallis test compared age across LPP, DLE and FFA. Two-sided p < 0.05 was considered significant. Groups with fewer than 5 patients (FFA, acne keloidalis, folliculitis decalvans, pseudopelade of Brocq) were described but not tested. Ethics. The study was approved by the Institutional Ethics Committee [Approval no. EC/214/2024, dated 28/12/2024] and followed the Declaration of Helsinki. Written informed consent (English, Hindi or Marathi) was obtained, with assent and guardian consent for minors, including specific consent for clinical and dermoscopic photography.

Diagnoses, age and sex Sixty-nine patients were studied. LPP (n = 41, 59.4%) and DLE (n = 21, 30.4%) accounted for 89.9% of cases; lymphocytic PCA (LPP, DLE, FFA) made up 65 patients (93.4%) (Table 1). Mean age was 36.87 +/- 13.87 years (median 35; range 6-66). The 21-30-year group was largest (n = 21, 30.4%), followed by 41-50 years (n = 16, 23.2%) and 31-40 years (n = 14, 20.3%); one patient (1.4%) was aged 10 years or younger and 5 (7.2%) were over 60. DLE patients were older than LPP patients (mean 42.8 +/- 12.8 vs 33.5 +/- 14.3 years; Mann-Whitney U = 263.0, p = 0.013), and age differed across LPP, DLE and FFA (Kruskal-Wallis H = 6.535, p = 0.038). There were 40 males (57.9%) and 29 females (42.0%) (M:F 1.38:1); the sex distribution did not differ between LPP and DLE (chi-square 0.142, p = 0.706). Acne keloidalis and folliculitis decalvans occurred only in males, and two of three FFA patients were female. Table 1: Diagnoses, age and sex distribution (n = 69) Diagnosis n (%) Age, mean +/- SD (range), years Male / Female Lichen planopilaris (LPP) 41 (59.4) 33.5 +/- 14.3 (6-66) 25 / 16 Discoid lupus erythematosus (DLE) 21 (30.4) 42.8 +/- 12.8 (22-65) 11 / 10 Frontal fibrosing alopecia (FFA) 3 (4.3) 36.7 +/- 5.7 (32-43) 1 / 2 Acne keloidalis (AK) 2 (2.9) 37.0 +/- 8.5 (31-43) 2 / 0 Folliculitis decalvans (FD) 1 (1.4) 32 1 / 0 Pseudopelade of Brocq (PPB) 1 (1.4) 54 0 / 1 Total 69 (100) 36.87 +/- 13.87 (6-66); median 35 40 / 29 LPP vs DLE age: Mann-Whitney U = 263.0, p = 0.013. Sex, LPP vs DLE: chi-square = 0.142, p = 0.706. Clinical features Hair loss was the commonest complaint (n = 65, 94.2%), followed by itching (n = 40, 58.0%); 21 patients (30.4%) were asymptomatic, including all three with FFA (Table 2). Increased dandruff (10/21 DLE vs 0/41 LPP; p < 0.001) and burning (5/21 DLE vs 0/41 LPP; p = 0.003) were significantly more frequent in DLE. Fifty-two patients (75.4%) had no systemic comorbidity; hypertension (n = 7, plus one with hypertension and prior brain-tumour surgery), diabetes mellitus (n = 3), thyroid disorder (n = 3), systemic lupus erythematosus (n = 2) and Rowell's syndrome (n = 1) were recorded. Nine DLE patients (42.9%) reported scalp depigmentation. Fifty-three patients (76.8%) were educated, with no significant LPP-DLE difference. A history of prior topical scalp application was present in 18 patients (26.1%), including all three with FFA. Among patients younger than 30 years, lesion duration ranged from 2 months to 10 years. On examination, follicular ostia were absent in 64 patients (92.8%) and scaling was present in 61 (88.4%). Oral mucosal involvement was noted in 4 patients (5.8%), eyebrow/eyelash involvement in 3 (4.3%; one FFA, two LPP), and nail dystrophy in one LPP patient. Twins with concordant asymptomatic hair loss were also seen. Table 2: Presenting symptoms and sociodemographic features: overall and LPP vs DLE Feature Total n (%), n = 69 LPP n (%), n = 41 DLE n (%), n = 21 p Hair loss 65 (94.2) 40 (97.6) 19 (90.5) 0.263 Itching 40 (58.0) 22 (53.7) 14 (66.7) 0.477 Asymptomatic 21 (30.4) 12 (29.3) 4 (19.0) 0.573 Pain on pressure 10 (14.5) 2 (4.9) 2 (9.5) 0.599 Increased dandruff 10 (14.5) 0 10 (47.6) < 0.001 Burning 6 (8.7) 0 5 (23.8) 0.003 Discharge 2 (2.9) 2 (4.9) 0 not tested Educated 53 (76.8) 33 (80.5) 14 (66.7) NS Prior topical application 18 (26.1) 12 (29.3) 2 (9.5) not tested Multiple symptoms could coexist. Percentages for the total column use n = 69. NS = not significant. Trichoscopic findings Lesional and perilesional trichoscopy was done in all 69 patients (Table 3). Structureless (white/ivory) areas were the commonest finding (n = 35, 50.7%), followed by perifollicular scaling (46.4%) and pigment incontinence (40.6%). Six features differed significantly between LPP and DLE: perifollicular scaling (63.4% vs 19.0%, p = 0.001), peripilar casts (36.6% vs 0%, p = 0.001) and pigment incontinence (58.5% vs 14.3%, p = 0.001) favoured LPP; follicular keratotic plugging (42.9% vs 9.8%, p = 0.006), follicular erythema (42.9% vs 9.8%, p = 0.006) and telangiectasia (42.9% vs 4.9%, p = 0.001) favoured DLE. Additional patterns seen in selected patients, and not quantified, were double-ring scales (n = 1), grey-brown globules, honeycomb pigmentation, white globules, fibrotic connecting beams, chrysalis-like structures and the contrast halo sign. Table 3: Trichoscopic features: overall and LPP vs DLE Feature Total n (%), n = 69 LPP n (%), n = 41 DLE n (%), n = 21 p Structureless areas 35 (50.7) 22 (53.7) 10 (47.6) 0.856 Perifollicular scaling 32 (46.4) 26 (63.4) 4 (19.0) 0.001 Pigment incontinence 28 (40.6) 24 (58.5) 3 (14.3) 0.001 Peripilar cast 17 (24.6) 15 (36.6) 0 0.001 Follicular erythema 16 (23.2) 4 (9.8) 9 (42.9) 0.006 Speckled pigmentation 16 (23.2) 8 (19.5) 6 (28.6) 0.627 Follicular keratotic plugging 13 (18.8) 4 (9.8) 9 (42.9) 0.006 Telangiectasia 12 (17.4) 2 (4.9) 9 (42.9) 0.001 White patchy scales 9 (13.0) 4 (9.8) 5 (23.8) 0.251 Perifollicular white halo 8 (11.6) 3 (7.3) 5 (23.8) 0.107 Loss of follicular ostia 5 (7.2) 4 (9.8) 1 (4.8) 0.654 Rosettes 4 (5.8) 1 (2.4) 3 (14.3) 0.109 Tufted hair 3 (4.3) 0 0 not tested Fisher's exact test where expected count < 5, otherwise chi-square with Yates correction. Features could coexist. The remaining cases belong to FFA, AK, FD and PPB. Histopathological findings Biopsy was done in all 69 patients (Table 4). Lymphocytic infiltrate was the commonest finding (n = 52, 75.4%), followed by fibrous tracts (37.7%), melanophages (31.9%) and lone (orphan) arrector pili muscle (29.0%). Fibrous tracts (46.3% vs 14.3%, p = 0.014) and lone arrector pili muscle (39.0% vs 9.5%, p = 0.019) were more frequent in LPP, whereas thickened basement membrane (42.9% vs 2.4%, p < 0.001) and follicular plugging (33.3% vs 4.9%, p = 0.005) were more frequent in DLE. Epidermal hyperplasia/hyperkeratosis showed a non-significant trend towards DLE (38.1% vs 14.6%, p = 0.077). Table 4: Histopathological features: overall and LPP vs DLE Feature Total n (%), n = 69 LPP n (%), n = 41 DLE n (%), n = 21 p Lymphocytic infiltrate 52 (75.4) 30 (73.2) 16 (76.2) 1.000 Fibrous tracts 26 (37.7) 19 (46.3) 3 (14.3) 0.014 Melanophages 22 (31.9) 15 (36.6) 5 (23.8) 0.465 Lone arrector pili muscle 20 (29.0) 16 (39.0) 2 (9.5) 0.019 Interface dermatitis 18 (26.1) 9 (22.0) 8 (38.1) 0.295 Epidermal hyperplasia/hyperkeratosis 16 (23.2) 6 (14.6) 8 (38.1) 0.077 Thickened basement membrane 10 (14.5) 1 (2.4) 9 (42.9) < 0.001 Pigment incontinence 10 (14.5) 8 (19.5) 2 (9.5) 0.472 Follicular plugging 9 (13.0) 2 (4.9) 7 (33.3) 0.005 Hair follicle preservation 9 (13.0) 5 (12.2) 4 (19.0) 0.473 Dilated vessels 4 (5.8) 1 (2.4) 3 (14.3) 0.109 Sclerosis (dermal) 3 (4.3) 1 (2.4) 2 (9.5) 0.263 Tests as in Table 3. VVG staining VVG was performed in 10 patients (6 LPP, 4 DLE) (Table 5). Wedge-shaped perifollicular fibrosis was seen in 5 of 6 LPP and 1 of 4 DLE biopsies, and broad tree-trunk-shaped fibrosis in 2 of 4 DLE and no LPP biopsies. Table 5. VVG pattern of perifollicular fibrosis (n = 10) Diagnosis VVG done, n Wedge-shaped n (%) Broad tree-trunk n (%) LPP 6 5 (83.3) 0 DLE 4 1 (25.0) 2 (50.0) Total 10 6 (60.0) 2 (20.0) One LPP and one DLE biopsy showed neither pattern. Trichoscopic-histopathological correlation Correlation was described qualitatively; no agreement statistic was calculated. Perifollicular scaling and peripilar casts corresponded to perifollicular lymphocytic inflammation, fibroplasia and follicular hyperkeratosis. Structureless areas corresponded to loss of follicles with replacement fibrosis and lone arrector pili muscle. Follicular keratotic plugging corresponded to histological follicular plugging and thickened basement membrane, and telangiectasia to dilated dermal vessels. Speckled pigmentation and trichoscopic pigment incontinence corresponded to melanophages and interface change with pigment incontinence.

In this cross-sectional study of 69 patients with PCA, lymphocytic subtypes accounted for 93.4% of cases, with LPP and DLE predominating. LPP and DLE differed in age, in two symptoms (burning, increased dandruff), in six trichoscopic features and in four histopathological features, and VVG patterns differed between the 10 biopsies stained. Trichoscopic and histological findings corresponded descriptively, but agreement was not quantified. Subtype distribution. LPP formed 59.4% and DLE 30.4% of our cohort, and FFA only 4.3%. A cross-sectional series using H&E and VVG reported LPP in 56.6% and DLE in 20.75% of 53 PCA patients [5], which is close to our LPP proportion. In contrast, the 22-clinic multicentre study found FFA to be the most frequent cicatricial alopecia (10.8% of all alopecia diagnoses, against 7.6% for LPP) [3]. These denominators differ from ours, which counts only PCA, so the figures cannot be compared directly. Referral pattern, ethnicity, and under-recognition of FFA in a hospital-based setting may all contribute, and the very small FFA group (n = 3) allows no firm inference. Age and sex. The male predominance in our cohort (M:F 1.38:1) was driven by LPP (1.56:1) and by acne keloidalis and folliculitis decalvans, which occurred only in men; male predominance in these two conditions is consistent with the multicentre data [3]. The multicentre series, however, reported marked female predominance in LPP (83%) and FFA (95%) [3], whereas our LPP patients were mostly male. A male excess was also noted in a retrospective North-East Indian series of 24 PCA patients (M:F 2:1) [7]. Health-seeking behaviour, concealment of hair loss in women with long hair, and hospital-based sampling may explain this, but we did not test these explanations. DLE was near-equal by sex (1.10:1) and its patients were older than those with LPP (p = 0.013); with 21 DLE patients this finding needs confirmation. Clinical features. Follicular ostia were absent in 92.8% of patients and nearly one-third were asymptomatic, which suggests that many patients present after substantial scarring has occurred. Burning and increased dandruff were reported only by DLE patients, which may help in the history, but the numbers are small. All three FFA patients and 26.1% of the whole cohort reported prior topical applications. This was self-reported, was not compared with a control group, and cannot be interpreted as causal. Trichoscopy. Perifollicular scaling and peripilar casts favoured LPP, in keeping with active perifollicular lichenoid inflammation, while follicular keratotic plugging, follicular erythema and telangiectasia favoured DLE. Studies of DLE report similar findings: follicular plugging and follicular red dots were more frequent in lesions of shorter duration, and linear vessels and structureless whitish areas in longer-standing lesions, in 28 Egyptian patients [9], and perifollicular whitish halo, follicular keratotic plugs and telangiectasia were the commonest criteria, with good dermoscopic-histopathological correlation, in non-scalp DLE [10]. Structureless areas were the commonest feature overall (50.7%) but did not differ between LPP (53.7%) and DLE (47.6%); this suggests that they mark the stage of fibrosis rather than the underlying disease. Lesional and perilesional frequencies were not reported separately, so the added value of perilesional trichoscopy cannot be judged from our data. Histopathology and correlation. Fibrous tracts and lone arrector pili muscle, features of follicular dropout, favoured LPP, whereas thickened basement membrane and follicular plugging favoured DLE. A lymphocytic infiltrate was absent in about one quarter of biopsies, which fits with late-stage disease or sampling of a fibrotic area. The pairings of trichoscopic features with histological substrates (for example, follicular keratotic plugging with follicular plugging and basement membrane thickening) are biologically plausible and in line with the literature [9,10]. However, our correlation is descriptive. The earlier Indian series reported a Cohen kappa of 0.89 between trichoscopic and histological diagnosis in 24 patients [7], and trichoscopic validity has been analysed formally elsewhere [6]. We calculated neither agreement nor sensitivity and specificity, and because final diagnoses were assigned partly on histology, our comparisons risk circularity. We therefore cannot state that trichoscopy can replace biopsy; our data support its use to guide biopsy-site selection. VVG staining. Wedge-shaped fibrosis in 5 of 6 LPP biopsies agrees with earlier work, but a previous series found this pattern in 54% of LPP and 55% of central centrifugal cicatricial alopecia (CCCA) biopsies and concluded that it is associated with, but not specific for, LPP [4]. Broad tree-trunk-shaped fibrosis was described as specific for CCCA, though absent in many CCCA cases [4]. We saw this pattern in 2 of 4 DLE biopsies, which is not the pattern reported in that series, and another study described absent upper and mid dermal elastic fibres in DLE (7 of 11 cases) [5]. In that study VVG increased diagnostic yield over H&E in routine practice (62.3% vs 24.5%) [5]. With only 10 selected biopsies and no CCCA in our cohort, our VVG results are hypothesis-generating and should not be taken as evidence that tree-trunk fibrosis distinguishes DLE. Clinical implications. Examining the whole scalp, trimming hair around the margin, and sampling the trichoscopically active area are practical steps that may improve biopsy yield. Trichoscopy complements, but does not replace, histopathology. Strengths and limitations. All 69 patients underwent both lesional and perilesional trichoscopy and a trichoscopy-guided biopsy, and VVG was added in a subset. Limitations are the single-centre, convenience-sampled, cross-sectional design; small non-LPP/DLE groups; VVG in only 10 patients selected on unstated criteria; no formal agreement statistics or blinded review; no adjustment for the many comparisons made (about 30 features compared between LPP and DLE, so some p-values near 0.05 may be chance findings); and no follow-up, so activity and treatment response could not be assessed.

In this tertiary-care cohort, PCA was predominantly lymphocytic (LPP 59.4%, DLE 30.4%). Perifollicular scaling, peripilar casts and pigment incontinence were associated with LPP, and follicular keratotic plugging, follicular erythema and telangiectasia with DLE; fibrous tracts and lone arrector pili muscle favoured LPP, and thickened basement membrane and follicular plugging favoured DLE. Trichoscopic features corresponded descriptively to histopathology and can help select the biopsy site. VVG patterns (n = 10) are preliminary. Larger, multicentre studies with blinded assessment, formal agreement statistics and consecutive VVG staining are needed.

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