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Frontal fibrosing alopecia (FFA) is an inflammatory cicatricial alopecia, which is considered to be a variant of lichen planopilaris. In addition to follicular changes, FFA often presents with associated cutaneous manifestations in most patients, including lichen planus pigmentosus, implantation line hypochromia and facial papules. The objective of the present article is to provide a detailed overview of the non-follicular cutaneous clinical manifestations of FFA and discuss their impact on the diagnosis and treatment of patients with this condition., (Copyright © 2024 Sociedade Brasileira de Dermatologia. Published by Elsevier España, S.L.U. All rights reserved.)

Lichen planus (LP) is a chronic, debilitating, inflammatory disease of the skin and mucous membranes that affects 1%-2% of Americans. Its molecular pathogenesis remains poorly understood, and there are no FDA-approved treatments. We performed single-cell RNA sequencing on paired blood and skin samples (lesional and nonlesional tissue) from 7 patients with LP. We discovered that LP keratinocytes and fibroblasts specifically secrete a combination of CXCL9, CXCL10, and CCL19 cytokines. Using an in vitro migration assay with primary human T cells, we demonstrated that CCL19 in combination with either of the other 2 cytokines synergistically enhanced recruitment of CD8+ T cells more than any individual cytokine. Moreover, exhausted T cells in lesional LP skin secreted CXCL13, which, along with CCL19, also enhanced recruitment of T cells, suggesting a feed-forward loop in LP. Finally, LP blood revealed decreased circulating naive CD8+ T cells compared with that in healthy volunteers, consistent with recruitment to skin. Molecular analysis of LP skin and blood samples increased our understanding of disease pathogenesis and identified CCL19 as a new therapeutic target for treatment.

Background and Aims: Diagnosing end-stage primary cicatricial alopecia (PCA) on routine histology is challenging since the major diagnostic feature (inflammatory infiltrate) may be minimal or absent. This study aimed to assess various staining patterns and diagnostic utility of elastic tissue staining by Verhoeff-Van Gieson (VVG) method and trichoscopy in PCA., Study Design: Cross-sectional study., Methods: Fifty-three patients clinically diagnosed with PCA underwent biopsy and trichoscopy in this cross-sectional study. Clinically active edge, if present, was biopsied. Twenty serial tissue sections were stained using H&E and VVG stain. Clinicopathological diagnoses were lichen planopilaris (LPP), discoid lupus erythematosus (DLE), folliculitis decalvans and unclassified PCA (UPCA) in 30 (56.6%), 11 (20.75%), 1 (1.9%) and 11 (20.75%) patients, respectively. Utility of VVG stain was ascertained considering clincopathological correlation (CPC) as the reference standard. Association of characteristic trichoscopic and VVG staining patterns was ascertained., Results: Diagnostic definition was achieved on VVG staining in 19/30 sections of LPP (wedge-shaped pattern) with 63.33% sensitivity; 7/11 cases of DLE (absent upper and mid dermal elastic fibres) with 63.64% sensitivity and 7/11 cases of UPCA (wedge-shaped pattern-3/7; recoil pattern-4/7). Routine histology suggested diagnosis only in 13/53 sections (24.52%). However, diagnosis on VVG staining corresponded with diagnosis on CPC in 33/53 cases (62.3%). Comparison of H&E versus VVG stain both overall and in the LPP and UPCA cohorts proved utility of VVG staining using Fisher's exact test (p<0.05). Statistical significance was also noted when trichoscopy was correlated with patterns on VVG staining (p<0.05)., Conclusion: Increased diagnostic yield is noted with trichoscopy and VVG stain in PCA especially when routine histopathology is non-diagnostic., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Backround: In this study, we aimed to investigate the potential contributions to the disease by examining the immunoreactivities of SPX in LP-affected skin tissue using immunohistochemical methods, in light of its recent prominence as a molecule related to diabetes mellitus, along with apoptosis and ferroptosis mediated by GPX4 and TRPM2 channels facilitating oxidative stress-induced cell death., Objective: This research explored the immunohistochemical expressions of TRPM2, GPX4, and SPX in Lichen Planus (LP) patients compared to healthy individuals., Materials and Methods: Forty skin samples were collected, split equally between LP patients and healthy controls, excluding those with other conditions. Samples underwent immunohistochemical staining for TRPM2, SPX, and GPX4, using secondary antibodies and chromogens AEC or DAB. Histoscores were calculated based on staining diffusiveness and severity. Statistical analyses were performed with SPSS 22.0, using t-tests and ANOVA, with significance set at p < 0.05., Results: There were no demographic differences between groups (p > 0.05). LP patients showed significantly lower TRPM2 and GPX4 histoscores and higher SPX histoscores compared to controls (TRPM2 and GPX4: p < 0.001, SPX: p < 0.001). Gender and age did not affect histoscores significantly., Conclusions: Findings suggest TRPM2, GPX4, and SPX play roles in LP pathogenesis, indicating a need for further molecular studies to clarify their involvement. This contributes to understanding LP beyond the traditional apoptosis perspective., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Lichen planus (LP) is a common inflammatory condition of unknown etiology that commonly affects the skin and mucous membranes. Optical coherence tomography angiography (OCTA) is a noninvasive technique for identifying early retinal vascular impairment in systemic disease without clinical damage by imaging deep and superficial capillary networks., Aims: To assess the impacts of LP on the choroid and assess vascular changes in retinal capillary density using OCTA., Methods: This single-center prospective case-control study included 30 therapeutic-naïve LP patients and 30 age and sex-matched healthy individuals. All study subjects underwent a complete ophthalmological examination, including best-corrected visual acuity (BCVA) measurement using a Snellen chart, slit-lamp biomicroscopy, intraocular pressure (IOP) measurement, and fundus examination. They were then examined using spectral domain OCT and choroidal thickness was measured. The vessel density of the superficial and deep capillary networks was measured and assessed using OCTA., Results: Patients had significantly thicker choroidal and retinal thickness than controls, with subfoveal, nasal, and temporal areas showing a significant difference. A significantly higher vascular density in the superficial capillary plexus, particularly in the nasal perifoveal area, was found compared to the control group. Significantly, higher vascular density in the deep capillary plexus in the parafoveal area compared to controls was reported. Significant correlations were found between visual acuity and IOP, and age, duration of disease, and severity of disease., Conclusions: This study is the first to reveal that LP patients exhibit choroidal changes and retinal vascular alterations compared to healthy controls., (© 2024. The Author(s), under exclusive licence to Royal Academy of Medicine in Ireland.)

Lichen planus (LP) is a highly prevalent inflammatory skin disease. While various clinical subtypes have been defined, detailed comparisons of these variants are lacking. This study aimed to elucidate differences in gene expression and cellular composition across LP subtypes. Lesional skin biopsies from 28 LP patients (classical, oral, genital, and lichen planopilaris) and seven non-diseased skin controls (NDC) were analyzed. Gene expression profiling of 730 inflammation-related genes was conducted using NanoString. Immune cell compositions were assessed by multiplex immunohistochemistry. Gene expression profiles revealed unique inflammatory signatures for each LP subtype. Lichen planopilaris exhibited the most divergence, with downregulated gene expression and upregulation of complement pathway genes ( C5-7 ), along with elevated M2 macrophages. Oral and genital LP demonstrated similar profiles with strong upregulation of TNF-related and Toll-like receptor-associated genes. Oral LP showed the highest upregulation of cytotoxicity-associated genes, as well as high numbers of CD8+ IL-17A+ (Tc17) cells (8.02%). Interferon gene signatures were strongly upregulated in oral and classical LP. The study highlights distinct differences in inflammatory gene expression and cell composition across LP subtypes, emphasizing the need for tailored therapeutic approaches.

Actinic lichen planus (ALP) is a rare photosensitive subtype of lichen planus (LP) with four major forms recognized: annular, pigmented (melasma-like), dyschromic, and classic lichenoid. The prevalence is highest among dark-skinned younger females residing in tropical and subtropical regions. There are very few reports of ALP across Europe, with most of the cases among individuals living in warm countries or in people of Middle Eastern and Indian ancestry. We report a case of a 68-year-old white man that presented with a 9-year history of a mildly pruritic solitary hyperpigmented patch on the tip of his nose. Histopathological examination demonstrated signs of classic LP with epidermal atrophy, pigmentary incontinence, and signs of solar elastosis. Based on these findings, a diagnosis of pigmented ALP was established. Topical pimecrolimus and tretinoin along with rigorous photoprotection proved effective, with mild residual hyperpigmentation after 6 months of treatment. Many differential diagnostic possibilities should be considered for such a lesion. Nevertheless, a biopsy and correlation of histopathological and clinical findings can shorten the time from onset to a proper diagnosis. Treating both the hyperpigmented and inflammatory component of this dermatosis is necessary, as well as strict long-term photoprotection to prevent recurrences.

Background: Lichen planopilaris (LPP) is a chronic lymphocytic skin disease manifested by progressive scarring alopecia. The diagnosis of LPP is made based on histopathological examination, although it is not always definite. The current study evaluates the effectiveness of non-invasive atomic force microscopy (AFM) hair examination in detecting morphological differences between healthy and diseased hair., Materials and Methods: Here, three to five hairs from lesional skin of 10 LPP patients were collected and examined at nine locations using AFM. At least four images were taken at each of the nine sites. Metric measurements were taken and metric (length, width, and scale step height) and morphological features (striated and smooth surface of scales, the presence of endocuticle and cortex, shape of scales edges, scratches, pitting, cracks, globules, and wavy edge) were compared with hair from healthy controls. In addition, areas on diseased hair where the process of pathological, unnatural delamination of the hair fiber occurs are described., Results: There was a statistically significant difference in the number of scratches in the initial sections of the LPP hair, in the intensity of wavy edges along the entire length of the tested hair, and in the number of scales with pitting in the middle section of the hair. In addition, a statistically significant higher number of scales with striated surface was found in LPP group starting at 3.5 cm from the root continuing towards the free end of the hair. Other morphological changes such as presence of cortex, globules, oval indentations, and rod-like macrofibrillar elements were also assessed, however, detailed results are not presented, as the differences shown in the number of these morphological changes were not significantly different., Conclusion: This publication outlines the differences between virgin, healthy Caucasian hair, and the hair of LPP patients. The results of this study can be used for further research and work related to LPP. This is the first attempt to characterize the hair of LPP patients using AFM., (© 2024 The Author(s). Skin Research and Technology published by John Wiley & Sons Ltd.)

Context.—: Clinical, dermoscopic, and histologic diagnostic criteria may overlap in cases with scarring and nonscarring alopecia, making diagnosis difficult for clinicians and pathologists. New histopathologic discoveries indicate that the cutaneous adnexal structural and homeostatic unit made up of the pilosebaceous unit, eccrine sweat gland coils (ESGCs), and dermal white adipose tissue may have a role in hair follicle renewal., Objective.—: To verify the presence of adipose tissue in the dermis at the level of the isthmus, infiltrating the bundles of the arrector pili muscle in biopsies from the scalp of 3 scarring alopecias: frontal fibrosing alopecia (FFA), fibrosing alopecia in a pattern distribution (FAPD), and lichen planopilaris (LPP)., Design.—: We performed a retrospective and descriptive survey of 71 female scalp biopsies from 2016 to 2022 diagnosed at the Dermatopathology Laboratory at Fluminense Federal University of Rio de Janeiro. Two pathologists reviewed and diagnosed the cases, correlating pathologic features with clinical and dermoscopic findings., Results.—: The histopathologic findings of adipose tissue infiltration in the dermis at the level of the isthmus and in the bundles of the arrector pili muscle and the displacement of ESGCs were more frequently identified in FFA, followed by FAPD and less frequently found in LPP., Conclusions.—: According to our research, adipose tissue infiltration in the dermis at the level of the isthmus and in the bundles of the arrector pili muscle and the displacement of ESGCs were observed in 3 scarring alopecias (FFA, FAPD, and LPP) and seems to be involved in the development of scarring alopecia., Competing Interests: The authors have no relevant financial interest in the products or companies described in this article., (© 2024 College of American Pathologists.)

As of now, there exists no established therapy for ELP. Retinoids, which are standard in treating cutaneous LP, do not exhibit positive effects in ELP. While topical glucocorticosteroids often yield favorable responses in esophageal inflammation, some cases prove recalcitrant or refractory. In such instances, various immunosuppressive therapies have been attempted with variable success.This report details a severe case of ELP that showed resistance to prednisolone, acitretin, alitretinoin, adalimumab, tacrolimus, hydroxychloroquine plus mycophenolate mofetil, and cyclophosphamide. The initiation of the JAK inhibitor tofacitinib induced an impressive clinical, endoscopic, and histological remission. This positive response to a JAK inhibitor is discussed in the context of our evolving understanding of the immune-mediated pathogenesis of this disease., Competing Interests: FS was funded by the Berta-Ottenstein-Programme for Advanced Clinician Scientists, Faculty of Medicine, University of Freiburg. The authors declare that they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Lichen planus is a chronic inflammatory dermatosis that can affect the skin, mucous membranes and nails. Cutaneous lichen planus lesions are best described by the "six Ps" - purple pruritic polygonal planar papules and plaques. Mucous membrane lesions are commonly associated with cutaneous lichen planus . Ocular involvement with lichen planus is rare and conjunctival involvement usually predominates, it can however be visually devastating. Ocular lichen planus often progresses to extensive conjunctival scarring which can be impossible to distinguish clinically from other cicatrising conjunctivitis, requiring histopathological confirmation. Here we review the ocular pathology of this condition., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract: Lichen linear planus is a rare variant of lichen planus that appears as pruritic, polygonal, purple papules in a blaschkoid distribution. This review critically assesses all reported cases of linear lichen planus (LLP) for proposed etiology, clinical and histologic traits, treatment options, and recurrence. A PubMed search from inception through March 2023, followed by article screening and full-text review, identified 51 unique cases of LLP. Data from each case including the sex of the patient, anatomic distribution of lesions, biopsy results, proposed etiology, treatment, and recurrence were recorded. LLP did not show a significant gender or age predilection, most frequently presented unilaterally with pruritus, and involved numerous anatomic regions. Various triggers including metal implants, vaccinations, infections, malignancy, and pregnancy were identified. The most common histopathologic descriptions included band-like lymphocytic or lichenoid infiltrate, basal liquefactive, vacuolar degeneration, hypergranulosis, hyperkeratosis, civatte or colloid bodies, melanin incontinence, and orthokeratosis. Treatment options, duration of treatment, and recurrence rate of LLP lesions were variable. Although LLP is rare, dermatologists should be aware of this presentation and appropriate diagnostic and treatment options because swift diagnosis can reduce patient morbidity., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Diseases in which cutaneous plasma cell infiltrates predominate are rare and usually of unknown etiology, including those that transition from benign to malignant, such as cutaneous plasmacytosis, multicentric Castleman disease, and extramedullary plasmacytoma. These diseases may present as purplish, reddish-brown cutaneous plaques or nodules. Here, we report an exceptional case of lichen planus (LP) in which the patient had classic histopathological features, but the infiltrating inflammatory cells were plasma cells with restricted light chain expression. The patient presented with severe rashes, including purplish-red plaques and nodules, erythema, and erosions in the palmoplantar area, verrucous hyperplasia of the oral mucosa, and anonychia of the toes. These findings suggest a possible role of plasma cells with restricted light chain expression in the LP. Clinicians should closely follow patients for changes in their rash, perform repeat biopsies if necessary, and regularly conduct multisystemic evaluations., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Red scalp is a common complaint that may constitute a diagnostic and therapeutic challenge in daily clinical practice. Among the numerous diseases to cause diffuse scalp erythema are psoriasis, seborrhoeic dermatitis, contact dermatitis, diffuse lichen planopilaris, dermatomyositis and scalp rosacea. Accurate diagnosis is crucial for optimal treatment outcomes. Histology most frequently discriminates the underlying condition, but it requires scalp biopsy. In many cases, the combination of clinical examination and trichoscopy is sufficient for establishing the correct diagnosis. The main trichoscopic features of psoriasis are silver-white scaling, regularly distributed dotted (glomerular) vessels or twisted red loops, and punctate haemorrhages. Yellowish-white scaling and thin arborizing vessels are typical features of seborrhoeic dermatitis. Contact dermatitis is characterized by the presence of yellow exudate and polymorphic vessels, while perifollicular scaling and erythema with the lack of follicular openings are typical findings in lichen planopilaris. In scalp dermatomyositis, tortuous and arborizing vessels with interfollicular and perifollicular pigmentation may be detected. The most characteristic features of scalp rosacea are perifollicular scaling and polygonal/arborizing vessels. This review also summarizes histological features and therapeutic options for these conditions., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Lichen sclerosus (LS) is a chronic inflammatory dermatosis primarily affecting the genitalia, commonly characterized by pearly-white papules and plaques. Although predominantly affecting females, LS can manifest across all age groups, with a bimodal distribution observed in prepubescent girls and postmenopausal women. This case report presents an unusual instance of exclusive extragenital LS in a 10-year-old girl, showcasing hyperpigmented patches and wrinkled plaques resembling lichen planus on her forearms and lower legs. Histopathological analysis confirmed LS, revealing distinctive epidermal changes and lymphocytic infiltrates. The absence of mucosal involvement and unique clinical presentation differentiated this case from typical LS manifestations. Treatment with topical clobetasol propionate demonstrated significant improvement in pruritus. Extragenital LS is infrequent, particularly among children, and its diagnosis necessitates a comprehensive clinicopathological correlation. The reported case contributes valuable insights into this uncommon variant, emphasizing the importance of accurate diagnosis and tailored treatment strategies. Additionally, it highlights the efficacy of high-potency topical corticosteroids in managing this condition.

Lichen planus is a chronic auto-inflammatory disease that primarily affects mucocutaneous regions. There are many variants of lichen planus including cutaneous, oral, nail, follicular, and erosive forms. Without any disease-specific treatment options, multi-variant lichen planus can be a challenging disease to manage. We present a 61-year-old woman with multivariant lichen planus that was refractory to numerous systemic and topical therapies. Subsequently, her cutaneous and vulvovaginal lesions improved with the use of oral baricitinib and the erosive oral lesions improved with topical ruxolitinib.

Lichen planus (LP) is a T-cell-mediated inflammatory disease affecting squamous epithelia in many parts of the body, most often the skin and oral mucosa. Cutaneous LP is usually transient and oral LP (OLP) is most often chronic, so we performed a large-scale genetic and epidemiological study of LP to address whether the oral and non-oral subgroups have shared or distinct underlying pathologies and their overlap with autoimmune disease. Using lifelong records covering diagnoses, procedures, and clinic identity from 473,580 individuals in the FinnGen study, genome-wide association analyses were conducted on carefully constructed subcategories of OLP (n = 3,323) and non-oral LP (n = 4,356) and on the combined group. We identified 15 genome-wide significant associations in FinnGen and an additional 12 when meta-analyzed with UKBB (27 independent associations at 25 distinct genomic locations), most of which are shared between oral and non-oral LP. Many associations coincide with known autoimmune disease loci, consistent with the epidemiologic enrichment of LP with hypothyroidism and other autoimmune diseases. Notably, a third of the FinnGen associations demonstrate significant differences between OLP and non-OLP. We also observed a 13.6-fold risk for tongue cancer and an elevated risk for other oral cancers in OLP, in agreement with earlier reports that connect LP with higher cancer incidence. In addition to a large-scale dissection of LP genetics and comorbidities, our study demonstrates the use of comprehensive, multidimensional health registry data to address outstanding clinical questions and reveal underlying biological mechanisms in common but understudied diseases., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are primary cicatricial alopecia that cause a major impact on quality of life due to irreversible hair loss and symptoms as itching, burning and pain. They are characterized by permanent loss of hair follicle stem cells (HFSCs) by pathomechanisms still poorly understood, resulting in poor efficacy of currently available treatments. Caveolae are flask-shaped lipid rafts invaginated within the plasma membrane of multiple cell types. Although their role in the HF physiology and pathophysiology is relatively unknown, we have previously demonstrated that the primary structural component of caveolae (caveolin-1 or Cav1) is upregulated in FFA. Thus, we propose to investigate the expression and localization of caveolae-associated structural proteins (Cav1, Cav2, and Cavin-1) and HFSCs (identified by K15) in both LPP and FFA. We analyzed 4 patients with LPP biopsied in affected and non-affected (NA) scalp, 4 patients with FFA biopsied in affected scalp and 4 healthy controls. Affected scalp of LPP and FFA demonstrated increased levels of Cav1 and Cavin-1 compared with HC and LPP-NA. Moreover, Cav1, Cav2 and Cavin1 all exhibit high colocalization with K15 and their expression appears to be negatively correlated, supporting the hypothesis that these proteins are important players in LPP/FFA and may serve as therapeutic targets in future treatments., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Context.—: Hypertrophic lichen planus (HLP) is a variant of lichen planus that can be difficult to diagnose based on histopathologic features alone. Thus, patient clinical history and clinicopathologic correlation are essential considerations to make the correct diagnosis., Objective.—: To discuss the clinical and histologic presentation of HLP and provide a thorough review of commonly encountered mimickers in the differential diagnosis., Data Sources.—: Data were derived from a literature review, personal clinical and research experiences, and a review of cases in the archives of a tertiary care referral center., Conclusions.—: In general, HLP involves the lower extremities and is characterized by thickened, scaly nodules and plaques that are often pruritic and chronic in nature. HLP affects both males and females and is most common in adults 50 to 75 years of age. Unlike conventional lichen planus, HLP tends to have eosinophils and classically displays a lymphocytic infiltrate most concentrated around the tips of rete ridges. The differential diagnosis for HLP is broad and encompasses numerous entities in many different categories, including premalignant and malignant neoplasms, reactive squamoproliferative tumors, benign epidermal neoplasms, connective tissue disease, autoimmune bullous disease, infection, and drug-related reactions. Therefore, a high index of suspicion must be maintained to avoid a misdiagnosis and potential inappropriate treatments., (© 2024 College of American Pathologists.)

Background and Objective: PD-1 inhibitors have revolutionized cancer therapies and are being used to treat an expanding array of cancers. To best serve patients, clinicians should be familiar with the spectrum of skin manifestations associated with PD-1 inhibitor therapy. Here, we report a unique case of hypertrophic lichen planus (HLP) in a 64-year-old man treated with pembrolizumab; the presentation initially suggested a squamous cell carcinoma (SCC) morphology, then evolved into a morphology more typical of hypertrophic lichen planus. This case underscores the need for caution in diagnosing eruptive SCCs associated with PD-1 inhibitor therapy. In such instances, maintaining a high suspicion for lichenoid reactions as sequelae of PD-1 inhibitor treatment and starting an empiric trial of therapy for lichenoid dermatitis may be warranted to ensure timely management of lesions., Methods: We describe a case of hypertrophic lichen planus mimicking squamous cell carcinoma in the setting of PD-1 inhibitory therapy with pembrolizumab. A PubMed literature review was conducted to identify other cases and determine the incidence of lichenoid reactions imitating squamous cell carcinoma in the setting of PD-1 inhibitor use., Results: Our case is one of the few available pieces of literature describing eruptive hypertrophic lichen planus imitating SCC in the setting of PD-1 inhibitor use. Initial skin nodule biopsy appeared histologically compatible with squamous cell carcinoma. Repeat biopsy of the skin lesions revealed histological features consistent with hypertrophic lichen planus. Over time, lower extremity lesions evolved into a more typical appearance of hypertrophic lichen planus. Treatment with topical 0.05% clobetasol ointment and oral acitretin 25 mg led to complete resolution of lesions within 2-3 months., Conclusions: This case underscores the significance of maintaining vigilance for lichenoid reactions as potential sequelae of PD-1 inhibitor therapy. It highlights the variability in initial presentation and the potential for lesions to transform over time. Timely recognition and appropriate management, including high-potency topical corticosteroids and oral acitretin, are crucial for achieving favorable outcomes in patients experiencing such reactions. More studies are necessary to fully analyze the rate of HLP occurrence as a consequence of PD-1 inhibitor use., (© 2024. The Author(s).)

Hydroxychloroquine is used for treatment of inflammatory diseases. It is considered to have few adverse effects. We report on a woman who developed a severe skin rash after intake of hydroxychloroquine, which she received for treatment of her lichen planopilaris. Based on the clinical, laboratory and histological findings the diagnosis of a drug reaction with eosinophilia and systemic symptoms (DRESS)-like drug reaction was established. Our case illustrates that hydroxychloroquine can lead to severe adverse effects in rare cases and that patients receiving this drug must be thoroughly informed., (© 2024. The Author(s).)

Background: Lichen planus pemphigoides (LPP), an association between lichen planus and bullous pemphigoid lesions, is a rare subepithelial autoimmune bullous disease. Mucous membrane involvement has been reported previously; however, it has never been specifically studied., Methods: We report on 12 cases of LPP with predominant or exclusive mucous membrane involvement. The diagnosis of LPP was based on the presence of lichenoid infiltrates in histology and immune deposits in the basement membrane zone in direct immunofluorescence and/or immunoelectron microscopy. Our systematic review of the literature, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, highlights the clinical and immunological characteristics of LPP, with or without mucous membrane involvement., Results: Corticosteroids are the most frequently used treatment, with better outcomes in LPP with skin involvement alone than in that with mucous membrane involvement. Our results suggest that immunomodulators represent an alternative first-line treatment for patients with predominant mucous membrane involvement., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Combemale, Bohelay, Sitbon, Ahouach, Alexandre, Martin, Pascal, Soued, Doan, Morin, Grootenboer-Mignot, Caux, Prost-Squarcioni and Le Roux-Villet.)

Objectives: Lichen planus (LP) and lichen sclerosus (LS) are the most common vulvar lichenoid dermatoses. The diagnostic challenges are due to site-specific variation in microscopic appearance and small-sized biopsies. Authentication of diagnostic criteria to distinguish LS and LP to uncover any resemblance or divergence in presentation of these conditions is attempted., Methods: Cases of vulvar LP and LS diagnosed between January 2012 to December 2022 were included. The clinical details included age, presenting symptoms, examination findings, and other organ involvement. Histopathological analysis of epidermal, dermal, and adnexal findings was done., Results: There were 28 cases of vulvar LP and 72 cases of LS, with a median age of 51 and 60 years, respectively. Depigmentation and atrophy were the major clinical features in LS, whereas ulcers/erosions and erythema were more prevalent in LP with a significantly higher incidence of oral involvement. The most diagnostic feature in LS was diffuse dermal sclerosis (76.8%) and interstitial pattern of inflammation (81.4%), whereas the characteristic features in LP cases was a lichenoid pattern of inflammation (85.7%), necrotic keratinocytes, and lymphocytic exocytosis. In 44.4% of LS, unconventional features like compact orthokeratosis, parakeratosis, thickened/wedge-shaped hypergranulosis, and sawtooth rete pegs were noted. Lichen sclerosus with lichenoid inflammation (21.4%) mimicked LP, from which it was distinguished by presence of thickened or diminished granular layer with basal melanin absence (60%) and dermal homogenization (80%)., Conclusion: Although the classical, well-established variant of LS poses no diagnostic difficulty, the unconventional variant may mimic LP. Identification of the subtle histological clues demonstrated in this study can help to arrive at the correct diagnosis., Competing Interests: The authors have declared they have no conflicts of interest., (Copyright © 2024, ASCCP.)

Lichen striatus (LS), linear psoriasis (LPs), linear cutaneous lupus erythematosus (LCLE) and linear lichen planus (LLP) often have similar clinical manifestations, which makes clinical diagnosis with the naked eye difficult; therefore, they are easily misdiagnosed. The purpose of this study was to determine whether reflectance confocal microscopy (RCM) is helpful in differentiating between these four linear dermatoses in children. This retrospective study included 14 patients with LS, nine with LPs, eight with LCLE and 12 with LLP. All patients were analysed using RCM, and biopsies were collected from lesions previously imaged by RCM. For LS, the dermal papillary rings were partially absent, but when present, manifested with small, homogeneously round, bright cells and occasionally highly refractive plump cellular structures, aggregated in clusters. LPs exhibited dark cyst-like structures with small, bright, round cells aggregated at the epidermal level; at the dermal-epidermal junction, homogeneously distributed, enlarged, faint dermal papillary rings and numerous enlarged low-refractive canalicular structures were observed in the superficial dermis. LCLE and LLP exhibited similar manifestations, including epidermal disarray, almost total absence of dermal papillary rings, and various sized refractive structures densely distributed in the dermis. The key distinguishing features of LCLE were the different sized structures mainly clustered around hair follicles, while LLP demonstrated dense structures with a scattered distribution. RCM may be used to distinguish between the key features of LS, LPs, LCLE and LLP in children.

Introduction: The diseases causing chronic diffuse alopecia and having similar clinical findings, namely chronic telogen effluvium, androgenetic alopecia, and the alopecia with overlapping features, should be differentiated. Recently, diffuse variants of lichen planopilaris have been described with histopathologic features of lichen planopilaris but clinically presenting with diffuse hair loss mostly in an androgenetic pattern., Objectives: To determine the accurate diagnosis underlying chronic diffuse alopecia in women by evaluating histopathologic findings., Patients and Methods: The study included 32 patients with diffuse and clinically noncicatricial alopecia for at least 6 months with no identifiable etiologic factor after general medical history, review of organ systems, and appropriate laboratory tests. Two 4 mm punch biopsies, one from vertex and the other from mid-occiput, were obtained and sectioned transversely., Results: The median age was 30.5 years (range: 22-40 years), and the median duration of hair loss was 4 years (range: 1.5-10 years). The histopathologic diagnosis was androgenetic alopecia, chronic telogen effluvium, and overlapping alopecia in 13 (40.6%), three (9.4%), and four (12.5%) patients, respectively. In the remaining 12 (32.5%) patients, a lichenoid inflammatory reaction affecting the infundibulum and isthmus was noted, and the probable diagnosis of diffuse variant of lichen planopilaris was made., Limitations: The retrospective nature and the small sample size., Conclusion: When the clinical diagnosis is not straightforward and no etiologic factor is found, histopathologic examination is mandatory for the accurate diagnosis of the disorder leading to chronic diffuse alopecia in women., (© 2023 the International Society of Dermatology.)

Background: Lichen planus is a chronic inflammatory disorder. Transcriptional coactivator with PDZ-binding motif (TAZ/WWTR1) is an important downstream effector of the Hippo pathway which regulates organ size and tissue homeostasis. But little is known about the role of TAZ in lichen planus so far., Objective: To explore the expression of TAZ in lichen planus and normal skin, and to discover the relationship between TAZ expression and the clinical characteristics of lichen planus patients., Methods: The method of immunohistochemistry was performed to quantify the expression of TAZ in 262 patients with lichen planus and 90 control tissues. Western blot and quantitative real-time reverse transcriptase-PCR (qRT-PCR) analysis were performed to examine and compare TAZ expression in 4 cases of fresh lichen planus lesions and normal skin tissues., Results: TAZ was weakly expressed in the basal layers of the epidermis in normal skin tissues with a positive rate of 52.22% (47/90). But in lichen planus, TAZ was strongly expressed in almost the entire epidermis with a positive rate of 81.30% (213/262), and the difference between the two groups was statistically significant (p<0.05). Additionally, TAZ expression was significantly related to the location of the lichen planus, clinical phenotype, smoking, and alcohol preference (p<0.05). Western blot and qRT-PCR showed that the expression of TAZ in protein and mRNA levels in four cases of lichen planus lesions was significantly higher than that in normal skin tissues., Conclusion: TAZ may play a regulatory role in the occurrence and development of lichen planus, which might provide a new perspective for studying pathogenesis and theoretical treatment targets., (© 2024 The Authors. Skin Research and Technology published by John Wiley & Sons Ltd.)

The Aim of the Study: Was to explore the accumulation and distribution of the photosensitizer Photoditazine in the oral mucosa when applied to pathological lesions in patients with severe forms of lichen planus., Material and Methods: A clinical and laboratory examination was carried out in 50 patients with severe forms of lichen planus (bullous and erosive-ulcerative) aged 18 to 70 years, including 6 men and 44 women. For autofluorescent imaging a LED device with a wavelength in the violet region of the spectrum (400±10 nm) was used. Quantitative registration of the kinetics of accumulation and distribution of the photosensitizer was carried out using the method of local fluorescence spectroscopy by measuring the fluorescence spectra., Results: The measurements were made before applying the photosensitizer, 10, 20 and 30 minutes after application. The study showed that in most patients with erosive-ulcerative and bullous forms of lichen planus, the accumulation of the photosensitizer in the lesions on the oral mucosa increased as the exposure time increased from 20 to 30 minutes. The fastest accumulation of the photosensitizer occurred in the areas of mucosal lesions with the most pronounced vascularization, namely, in the area of the tongue and the bottom of the oral cavity., Conclusion: Using the method of local fluorescence spectroscopy, the kinetics of accumulation and destruction of photosensitizer in pathological areas of the oral mucosa was determined, and therefore the optimal time of laser exposure to the lesion was determined.

Squamous cell carcinoma (SCC) is a known sequela of chronic inflammatory conditions of the skin. Labial discoid lupus erythema-tosus (DLE), oral lichen planus (OLP), and lichen sclerosus have a relatively short lag time from dermatosis onset to manifestation of malignancy; cutaneous DLE, hypertrophic lichen planus, chronic wounds, hidradenitis suppurativa (HS), and necrobiosis lipoidica can be present for decades before an associated malignancy is observed. Vigilant monitoring is essential for orolabial DLE, chronic HS, and chronic wounds because malignancies in these settings are particularly aggressive and often fatal. We summarize what is known about the nature and demographics of SCC arising within chronic inflammatory dermatoses, emphasizing lag time from dermatosis diagnosis to malignancy onset of common inflammatory conditions.

Lichen planus (LP) presents with a range of clinical subtypes. It can affect the outer skin, involve the nails and present with alopecia and mucosal symptoms to varying degrees. LP of the outer skin mostly shows a self-limiting course; however, this is not the case for lichen planopilaris and the mucosa-affecting subtypes. The pathogenesis of LP is still incompletely understood. As a result, an effective, targeted therapy is currently lacking and different immunomodulatory approaches are being used in clinical practice. The management of patients with severe oral LP mucosae can be particularly challenging. Although the true risk remains controversial, oral LP is considered a risk factor for the development of squamous cell carcinoma and there is a need for regular screening. The quality of life in patients with LP is significantly impaired because of frequent clinical visits, pain, soreness, inability to eat certain foods, side effects to medication, frustrating therapy attempts and worry regarding cancer risk. We highlight here the advantages of an interdisciplinary dermatology and oral surgery clinic, which can address the domains of tooth status, nutrition, pain and malignant transformation and optimized patient management., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Acquired dermal macular hyperpigmentation (ADMH), previously known as macular pigmentation of uncertain etiology (MPUE), is an umbrella concept that unifies the distinct but overlapping acquired dermal pigmentary disorders like lichen planus pigmentosus, ashy dermatosis, erythema dyschromicum perstans, Riehl's melanosis and pigmented contact dermatitis. All of these disorders usually lack a clinically apparent inflammatory phase, are characterised by dermal pigmentation clinically and histologically, and have a variable protracted disease course. Recently, a proposal has been made to classify these disorders into those with and without contact sensitisation. Dermoscopy is essentially similar across the spectrum of these disorders, and is useful for diagnosis and therapeutic response monitoring. Scoring system has been validated for the same. The treatment of ADMH remains challenging, with multiple topicals, oral therapies including mycophenolate mofetil, and lasers tried. Need of the hour is randomised controlled trials to enhance the therapeutic armamentarium., (© 2023 the International Society of Dermatology.)

Background: Lichen planus (LP) is a chronic inflammatory disorder caused by an autoimmune attack by cytotoxic T-cells. The clinical course is variable, with episodes of remission and exacerbation. A clinicopathological scoring system for cutaneous LP is not available for effectively assessing disease severity and monitoring treatment response. This study was designed with the aim of proposing an objective and reproducible scoring system, comprising histopathological features of active and chronic disease, and to correlate these scores with clinical morphology groups., Methodology: This is a retrospective study of 200 cases of cutaneous LP, which were categorized into five clinical groups (I-V) at the time of biopsy. The corresponding histopathological feature was assigned a score based on feature of active and chronic disease. Individual scores were summated to calculate a histopathological index (index [AI] and chronicity index [CI]). The comparison of indices between various clinical groups was performed by Mann-Whitney U test., Results: The median AI was lowest (1) for post-inflammatory hyperpigmentation (clinical group I) and highest (7) for the bullous group (clinical group IV). The median CI (7) was highest for the scarring group (clinical group V). The difference between median AI of clinical group I (post-inflammatory hyperpigmentation) and rest of the groups (clinical groups II, III, IV, and V) was statistically significant (p value <0.05)., Conclusion: We present this clinico-histopathological scoring system as a reliable and facile method of assessing the activity and severity of LP., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Frontal fibrosing alopecia (FFA) is a cicatricial alopecia affecting the frontotemporal hairline. Given that this scarring, immune-mediated follicular destruction most commonly affects postmenopausal Caucasian women, researchers have postulated that there are hormonal and genetic components; however, the etiology of FFA is still unknown. Recently, dermatologists have reported cases of FFA as being potentially caused by cosmetic products, such as sunscreen and shampoo. Therefore, this systematic review and meta-analysis intend to be the first to analyze the relationship between FFA and cosmetic/personal care products and treatments, including sunscreen, moisturizer, foundation, shampoo, conditioner, hair mousse, hair gel, hair dye, hair straightening/rebonding, chemical/laser facial resurfacing, aftershave, and facial cleanser., Methods: The Cochrane, PubMed, EMBASE, and Medline (Ovid) databases were searched for the relevant studies from the date of inception to August 2022. Case-control, cross-sectional, and cohort studies examining the effects of cosmetic/personal care product use on FFA, available in English full-text, were included. Analyses were performed using Review Manager, version 5.4. Results were reported as an odds ratio (OR) with a 95% confidence interval (CI); p values < 0.05 were considered significant., Results: Nine studies were included in our quantitative analyses, totaling 1,248 FFA patients and 1,459 controls. There were significant positive associations found for FFA and sunscreen (OR 3.02, 95% CI 1.67-5.47; p = 0.0003) and facial moisturizer (OR 2.20, 95% CI 1.51-3.20; p < 0.0001) use. Gender sub-analyses demonstrated a positive association for FFA and facial moisturizer in men (OR 5.07, 95% CI 1.40-18.32; p = 0.01), but not in women (OR 1.58, 95% CI 0.83-2.98; p = 0.16). Both gender sub-analyses were significantly positive for the association with facial sunscreen (Male OR 4.61, 95% CI 1.54-13.78, p = 0.006; Female OR 2.74, 95% CI 1.32-5.70, p = 0.007). There was no association found for a facial cleanser (OR 1.14, 95% CI 0.33-1.52; p = 0.51), foundation (OR 1.13, 95% CI 0.83-1.55; p = 0.21), shampoo (OR 0.49, 95% CI 0.22-1.10; p = 0.08), hair conditioner (OR 0.81, 95% CI 0.52-1.26; p = 0.35), hair mousse (OR 1.37, 95% CI 0.75-2.51; p = 0.31), and hair gel (OR 0.90, 95% CI 0.48-1.69; p = 0.74), hair dye (OR 1.07, 95% CI 0.69-1.64; p = 0.77), hair straightening/rebonding (OR 0.88, 95% CI 0.08-9.32; p = 0.92), hair perming (OR 1.41, 95% CI 0.89-2.23; p = 0.14), facial toner (OR 0.51, 95% CI 0.12-2.21; p = 0.37), or aftershave (OR 1.64, 95% CI 0.28-9.49; p = 0.58)., Conclusions: This meta-analysis strongly suggests that leave-on facial products, facial sunscreen and moisturizer, are associated with FFA. While the association with facial moisturizer did not persist when stratifying for female populations, gender sub-analyses remained significant for a facial sunscreen. There was no significant relationship found with hair products or treatments. These findings suggest a potential environmental etiology in the development of FFA, particularly UV-protecting chemicals., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)