Frontiers in Lichen Planopilaris and Frontal Fibrosing Alopecia Research: Pathobiology Progress and Translational Horizons

Compound Follicles in Folliculitis Decalvans Do Not Contain Vellus and Retained Telogen Follicles-A Pilot Histopathologic Series on Polytrichia

BACKGROUND

Polytrichia is a common clinical and trichoscopic feature in folliculitis decalvans (FD) that morphologically corresponds to compound follicular structures (CFS) of six or more follicles sharing a single infundibulum, surrounded by fibrosis.

OBJECTIVES

To characterize the type of follicles in the CFS in scalp biopsy specimens from FD.

METHODS

We retrospectively reviewed 10 scalp biopsy specimens obtained by using the trichoscopy-guided approach from the affected scalp of patients diagnosed with early-stage FD between 2018 and 2023. We assessed the number and type of follicles within the CFS on horizontal sections.

RESULTS

The total number of assessed follicles was 205, out of which 159 were part of CFS. Of those, 156 were terminal follicles (146 anagen and ten telogen), three intermediate, and zero vellus follicles. Other common findings included dense mixed cell infiltrate consisting of histiocytes, plasma cells, lymphocytes, neutrophils, and eosinophils; psoriasiform hyperplasia; and fragmented hair shafts.

CONCLUSIONS

We show that CFS in FD are composed largely of terminal anagen follicles. This may help with further understanding of the disease.

Frontal Fibrosing Alopecia: An Update

In this review, we discuss recent developments in our understanding of frontal fibrosing alopecia, a disease that has become increasingly common and widespread since its first description in 1994. An inherited predisposition to frontal fibrosing alopecia, previously suspected from the occurrence of familial cases, has been confirmed through genetic studies. Nevertheless, the epidemiology continues to implicate environmental factors in the aetiology. The search has focussed mainly on personal skin care products such as facial moisturisers and UV filters, and there is also some evidence implicating exogenous oestrogens, but confirmation of direct causal links has so far proved elusive. The pathologic mechanisms underlying follicular deletion are being clarified, including the nature of the inflammatory component, the loss of follicular immune privilege in the bulge region and the role of epithelial-mesenchymal transition in the scarring process. Lichen planus pigmentosus, a common accompaniment to frontal fibrosing alopecia in those with darker skin, is probably a feature of the same pathology affecting interfollicular epidermis, rather than a co-morbidity, and may offer new clues to the aetiology. Treatment is still based largely on retrospective case series and variable endpoints. However, methods for assessing frontal fibrosing alopecia and monitoring treatment responses have been strengthened and randomised controlled trials with novel agents (e.g. Janus kinase inhibitors) are in progress. As the main aim of effective treatment is to prevent disease progression, early diagnosis will remain an important target, as will prevention in the longer term.

Clinical and demographic characteristics of frontal fibrosing alopecia in a dermatology referral center in Bogota, Colombia: a descriptive cross-sectional study

Background

Frontal fibrosing alopecia (FFA) is a type of scarring alopecia that is characterized by a symmetrical recession of the frontal/temporal hairline. Despite growing interest in this pathology, there is scarce data on its epidemiology in Latin American countries such as Colombia.

Objective

To estimate the frequency and describe the clinical manifestations and factors associated with FFA.

Methods

This descriptive cross-sectional study reviewed the electronic health records of adult patients diagnosed with FFA at a referral center in the city of Bogota, Colombia, between 2018 and 2021.

Results

Of the 1506 patients diagnosed with scarring alopecia, 213 fully met the selection criteria (14.14%). Patients had a median age at diagnosis of 60 years (Q1-Q3: 49-67 years) and were more frequently female (95.31%). Concurrent eyebrow alopecia was the most frequent clinical presentation (56.34%). Perifollicular desquamation was present in 114 patients (53.52%), perifollicular erythema in 56 (26.29%), and both features simultaneously in 35 (16.43%). Sunscreen use was reported by 116 (54.46%) and facial moisturizers by 38 (17.84%), both of which have been reported as risk factors.

Limitations

The small sample size and the lack of racial and geographical diversity in the subjects.

Conclusion

This study provides baseline epidemiological data in a Colombian sample. Sex, location of alopecia, and symptoms were consistent with those reported in the literature, but age at presentation, tobacco use, use of wigs, and dyes differed from those reported in other countries.

Lichen Planopilaris Trichoscopy in Caucasian Scalp: A Review

Background

Lichen planopilaris (LPP) is a primary lymphocytic cicatricial alopecia characterized by several different patterns of permanent hair loss.

Summary

Trichoscopy plays an essential role in the context of LPP, as recognizing the distinctive signs of the disease facilitates the diagnosis of all forms of lichenoid alopecia.

Key Messages

This review aimed to recognizing the trichoscopic signs early on, enabling timely intervention, potentially preventing the disease from advancing to its permanent scarring stage.

Frontal Fibrosing Alopecia: A Comprehensive Guide for Cosmetic Dermatologists

Frontal fibrosing alopecia (FFA) is an inflammatory, scarring hair loss that commonly affects postmenopausal women and presents as frontal hairline recession, facial papules, loss of eyebrows, and facial hyperpigmentation. Because of the chronic, progressive nature of this disease and its important impact on aesthetic appearance, patients often consult dermatologists to improve unwanted FFA symptoms. Cosmetic practices including the use of non-ablative lasers, autologous fat injections, and oral isotretinoin can improve FFA-associated facial vein prominence, atrophic indentations, and facial papules, respectively. On the other hand, while exact etiology underlying FFA development remains unclear, some procedures including deep chemical peels and ablative laser therapies have been shown to induce facial scarring and are contraindicated in patients with FFA. In the same way, some cosmetic ingredients can possibly be a triggering or worsening factor for FFA as well. Therefore, it is essential for dermatologists to be aware of both the benefits and risks of cosmetic treatments in patients with diagnosed or suspected FFA. This comprehensive review aims to outline the key cosmetic products and procedures that may be useful in patients with FFA and those which should be considered contraindicated.

Extra-follicular cutaneous manifestations of frontal fibrosing alopecia

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.

Refractory alopecia areata with single hairs imitating frontal fibrosing alopecia: a prospective observational study

BACKGROUND

Lonely hair sign is considered as a clue to the diagnosis of frontal fibrosing alopecia (FFA).

OBJECTIVE

To report an undescribed variant of alopecia areata (AA) with which the patient developed single hairs and other features similar to FFA and to determine the underlying mechanism.

METHODS

We conducted a prospective observational study in patients who presented with receding hairline and single hairs, evaluating the clinical, trichoscopic, and histological features and their correlation. Immunochemistry studies were performed to describe the microenvironment.

RESULTS

Eighteen patients were enrolled in the study. Despite the similarity to FFA clinically, these patients showed different histopathology which revealed a normal number of pilosebaceous units, one anagen hair in one or more pilosebaceous units, and others in telogen stage, consistent with single hairs under the naked eye or under trichoscopy. The severity of the hair loss assessed by SALT was no more than 50, but the response to conventional therapy was poor.

CONCLUSIONS

This study reports a unique variant of AA. The pathological basis is an increase in the telogen hair follicles, with one anagen hair in one or more pilosebaceous units. Minimal inflammation consisting of CD3+ T lymphocytes and mast cells was demonstrated in the microenvironment.

Controlling Hair Loss by Regulating Apoptosis in Hair Follicles: A Comprehensive Overview

Apoptosis is a physiological process that occurs in all cell types of the human body, and it profoundly changes the fate of hair by affecting hair follicle cells. This review outlines the cellular changes, intrinsic biochemical characteristics, and mechanisms underlying apoptosis and summarizes the hair follicle life cycle, including development, cycle stages, and corresponding cellular changes. Finally, the relationship between apoptosis and the hair cycle is discussed and the significance of apoptosis in hair loss conditions and drug treatments is highlighted. Apoptosis induces cellular changes and exhibits distinctive properties through intricate signaling pathways. Hair follicles undergo cyclic periods of growth, regression, and dormancy. Apoptosis is closely correlated with the regression phase by triggering hair follicle cell death and shedding. Regulation of apoptosis in hair follicles plays an essential role in hair loss due to maladies and drug treatments. Mitigating apoptosis can enhance hair growth and minimize hair loss. A comprehensive understanding of the correlation between apoptosis and the hair cycle can facilitate the development of novel treatments to prevent hair loss and stimulate hair regeneration.

A Retrospective Study of Frontal Fibrosing Alopecia from North-East India

Background

Frontal fibrosing alopecia (FFA) is an important cause of scarring alopecia seen mostly in post-menopausal women but sometimes in pre-menopausal women and men. Although considered a variant of lichen planopilaris due to its histopathological characteristics, it has distinct clinical features and associations, which make it a unique entity. We hereby report a series of patients with FFA from North-East India.

Aims and Objective

This study aimed to analyse the clinical and histopathological characteristics of FFA.

Materials and Methods

We retrospectively analysed clinical records and histopathological features of FFA cases diagnosed in the Dermatology Outpatient Department from April 2013 to February 2023.

Results

A total of 21 patients, who were diagnosed with FFA from April 2013 to February 2023, were analysed. Of these, 19 patients were female, with a male-to-female ratio of 9.5:1. The mean age of study population was 48.33 years. The majority of the patients were from the post-menopausal age group (15/19 females, 78.94%). Lichen planus pigmentosus (6, 28.57%) was the most commonly associated disease, followed by androgenetic alopecia and lichen planopilaris (2 each, 9.52%). The main histological features noted were perifollicular lymphocytic infiltrate in 18 (85.71%), followed by hydropic degeneration of basal follicular keratinocytes in 15 (71.42%) and melanin incontinence in 14 (66.66%) patients.

Conclusion

Our study is the first study from North-East India focusing on the clinical presentation and histopathological characteristics of FFA. Furthermore, with respect to the recent development in FFA, our study attempted to determine the clinical significance of the proposed criteria for the diagnosis of FFA patients by Tolkachjov et al. (2018), viz. International FFA Cooperative Group Criteria (2021).

Recent Advances in Understanding of the Etiopathogenesis, Diagnosis, and Management of Hair Loss Diseases

Hair-loss diseases comprise heterogenous conditions with respective pathophysiology and clinicopathological characteristics. Major breakthroughs in hair follicle biology and immunology have led to the elucidation of etiopathogenesis of non-scarring alopecia (e.g., alopecia areata, AA) and cicatricial alopecia (e.g., lichen planopilaris, LPP). High-throughput genetic analyses revealed molecular mechanism underlying the disease susceptibility of hair loss conditions, such as androgenetic alopecia (AGA) and female pattern hair loss (FPHL). Hair loss attracted public interest during the COVID-19 pandemic. The knowledge of hair loss diseases is robustly expanding and thus requires timely updates. In this review, the diagnostic and measurement methodologies applied to hair loss diseases are updated. Of note, novel criteria and classification/scoring systems published in the last decade are reviewed, highlighting their advantages over conventional ones. Emerging diagnostic techniques are itemized with clinical pearls enabling efficient utilization. Recent advances in understanding the etiopathogenesis and management for representative hair diseases, namely AGA, FPHL, AA, and major primary cicatricial alopecia, including LPP, are comprehensively summarized, focusing on causative factors, genetic predisposition, new disease entity, and novel therapeutic options. Lastly, the association between COVID-19 and hair loss is discussed to delineate telogen effluvium as the predominating pathomechanism accounting for this sequela.

Protein profiling of forehead epidermal corneocytes distinguishes frontal fibrosing from androgenetic alopecia

Protein profiling offers an effective approach to characterizing how far epidermis departs from normal in disease states. The present pilot investigation tested the hypothesis that protein expression in epidermal corneocytes is perturbed in the forehead of subjects exhibiting frontal fibrosing alopecia. To this end, samples were collected by tape stripping from subjects diagnosed with this condition and compared to those from asymptomatic control subjects and from those exhibiting androgenetic alopecia. Unlike the latter, which exhibited only 3 proteins significantly different from controls in expression level, forehead samples from frontal fibrosing alopecia subjects displayed 72 proteins significantly different from controls, nearly two-thirds having lower expression. The results demonstrate frontal fibrosing alopecia exhibits altered corneocyte protein expression in epidermis beyond the scalp, indicative of a systemic condition. They also provide a basis for quantitative measures of departure from normal by assaying forehead epidermis, useful in monitoring response to treatment while avoiding invasive biopsy.