Lichenoid folliculitis: A unifying concept

Unveiling a Shared Precursor Condition for Acne Keloidalis Nuchae and Primary Cicatricial Alopecias

Purpose

Small observational studies suggest subclinical disease occurrence in the normal-appearing scalp zones of several primary cicatricial alopecias. To aid patient management, we began routinely evaluating the entire scalp of patients with acne keloidalis nuchae (AKN), including trichoscopy-guided biopsies.

Patients and Methods

This retrospective study evaluated 41 patients sequentially presenting with AKN at a single clinic between June and December 2022. Primary lesions and normal-appearing scalp in the superior parietal scalp at least 5 cm away from AKN-affected zones were clinically evaluated, and areas showing perifollicular erythema or scales/casts on trichoscopy were biopsied and histologically analyzed.

Results

Forty-one men with AKN, including 20 men of African descent, 17 Hispanic, and 4 European-descended Whites, were evaluated. All patients, including 22% with associated folliculitis decalvans, showed scalp-wide trichoscopy signs of perifollicular erythema or scaling in normal-appearing scalp areas. All patients showed histologic evidence of perifollicular infundibulo-isthmic lymphocytoplasmic infiltrates and fibrosis (PIILIF), with 96% showing Vellus or miniaturized hair absence. PIILIF was often clinically mistaken for seborrheic dermatitis (44-51%). All White patients had mild papular acne keloidalis nuchae lesions mistaken for seborrheic dermatitis.

Conclusion

PIILIF may be a precursor to a wide spectrum of primary cicatricial alopecias, including AKN and folliculitis decalvans. This finding carries implications for the early diagnosis and management of AKN and other primary cicatricial alopecias.

Trichoscopy for the Hair Transplant Surgeon-Assessing for Mimickers of Androgenetic Alopecia and Preoperative Evaluation of Donor Site Area

Preoperative diagnostic confidence and donor site assessment are important for all hair transplant surgery patients. While the majority of patients seek hair transplantation for male or female pattern hair loss (androgenetic alopecia [AGA]), there are mimickers that must be differentiated from patterned hair loss, as they alter the candidacy of the patient for transplantation. They are termed mimickers as they also can present with patterned hair loss. The use of trichoscopy has become increasingly popular for such use. Patterned hair loss mimickers, which include the underappreciated alopecia areata incognita (AAI) and fibrosing alopecia in patterned distribution (FAPD), can be identified clinically with key trichoscopic findings such as yellow dots and peripilar casts, respectively, that correlate with their histologic diagnosis. Donor hair density and putative hair pathology of the safe donor area can also by assessed via trichoscopy. This article discusses the use of trichoscopy, particularly for diagnosing mimickers of patterned hair loss as well as preoperative donor site assessment.

Clinicopathological characteristics and treatment outcomes of fibrosing alopecia in a pattern distribution: A retrospective cohort study

BACKGROUND

Fibrosing alopecia in a pattern distribution (FAPD) is a primary cicatricial alopecia considered a subtype of lichen planopilaris (LPP).

OBJECTIVE

The clinical and histopathological features, and treatment response of 24 female patients with FAPD were evaluated.

METHODS

Demographic, clinical, histopathological and treatment data of patients with FAPD were retrospectively collected.

RESULTS

Twenty-four women were included (mean age 60.7 years). The mean Lichen Planopilaris Activity Index score was 1.50, and the median Sinclair grade was 3. Twelve patients had diffuse alopecia in the centroparietal region, four had frontal accentuation and eight had vertex accentuation of hair loss. Eight had associated loss of facial hair. Predominant trichoscopic features included hair shaft diameter variability (100%), perifollicular erythema and/or scaling (95%) and loss of follicular ostia (95%). Histopathological examination revealed features of scarring alopecia with interface changes in follicular epithelia mainly targeting terminal and intermediate hairs, and less frequently, vellus hairs. Treatment with hair growth-promoting, anti-inflammatory and anti-androgen agents arrested disease progression in 14 patients and resulted in hair regrowth in two patients. Six patients had progression of their hair loss in spite of treatment.

LIMITATIONS

Referral bias to a specialist hair clinic, retrospective design and small sample size.

CONCLUSIONS

We present clinicopathological features of FAPD which can aid in the diagnosis of this insidious scarring alopecia. Our findings suggest a more favourable outcome if treatment is initiated in early stages of the disease.

Comedone-Like Lesions as a Manifestation of Lichen Planopilaris beyond the Scalp: A Case Report with Dermoscopic Features and Literature Review

Lichen planopilaris is a rare inflammatory condition that is also known as follicular lichen planus. Although the condition commonly affects the scalp, it sometimes involves the other regions of the body with a variety of clinical presentations. The involvement beyond the scalp is considered to be a generalized nature of disease process. In this report, we present a case of generalized follicular lichen planus in a 34-year-old Thai female presenting with comedone-like lesions on the trunk and extremities as well as scarring alopecia on the scalp. Dermoscopic features were also discussed.

Destruction of the stem cell Niche, Pathogenesis and Promising Treatment Targets for Primary Scarring Alopecias

The Primary Scarring Alopecias are characterised by the irreversible destruction and fibrosis of hair follicles, leading to permanent and often disfiguring loss of hair. The pathophysiology of these diseases is not well understood. However, follicular-fibrosis and loss of the stem-cell niche appears to be a common theme. This review explores the pathogenesis of primary scarring alopecias, asking what happens to the stem cells of the hair follicle and how they may contribute to the progression of these diseases. Bulge-resident cells are lost (leading to loss of capacity for hair growth) from the follicle either by inflammatory-mediate apoptosis or through epigenetic reprogramming to assume a mesenchymal-like identity. What proportion of bulge cells is lost to which process is unknown and probably differs depending on the individual PCA and its specific inflammatory cell infiltrate. The formation of fibroblast-like cells from follicular stem cells may also mean that the cells of the bulge have a direct role in the pathogenesis. The identification of specific cells involved in the pathogenesis of these diseases could provide unique diagnostic and therapeutic opportunities to prevent disease progression by preventing EMT and specific pro-fibrotic signals.

Frontal fibrosing alopecia shows robust T helper 1 and Janus kinase 3 skewing

BACKGROUND

Frontal fibrosing alopecia (FFA) is a scarring alopecia with unclear pathogenesis and a progressive course. The disease has a major impact on patients' quality of life and there is a lack of effective treatment to halt disease progression.

METHODS

We profiled lesional and nonlesional scalp biopsies collected in 2017 from patients with FFA (n = 12) compared with scalp biopsies from patients with alopecia areata (AA) (n = 8) and controls (n = 8) to evaluate gene and protein expression, including the primary outcome (CXCL9). We determined significant differences between biomarkers using a two-sided Student's t-test adjusting P-values by false discovery rate.

RESULTS

Significant increases were seen in CD8+ cytotoxic T cells, CD11c+ dendritic cells, CD103+ and CD69+ tissue-resident memory T cells in FFA and AA vs. control scalp (P < 0·05), with corresponding significantly upregulated granzyme B mRNA, particularly in FFA (P < 0·01). In AA, cellular infiltrates were primarily concentrated at the bulb, while in FFA these were mainly localized at the bulge. FFA demonstrated significant upregulation of T helper 1/intereferon (IFN) (IFN-γ, CXCL9/CXCL10), the Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathway (STAT1, JAK3) and fibrosis-related products (vimentin, fibronectin; P < 0·05), with no concomitant downregulation of hair keratins and the T-regulatory marker, forkhead box P3, which were decreased in AA. The stem cell markers CD200 and K15 demonstrated significantly reduced expression only in FFA (P < 0·05).

CONCLUSIONS

These data suggest that follicular damage and loss of stem cells in FFA may be mediated through immune attack in the bulge region, with secondary fibrosis and reduced but still detectable stem cells. JAK/STAT-targeting treatments may be able to prevent permanent follicular destruction and fibrosis in early disease stages.

[Postmenopausal lichen planopilaris also known as fibrosing frontotemporal alopecia Kossard : An evidence-oriented practical guide to treatment from the University of the Saarland, Hair Research Center of the Dr. Rolf M. Schwiete Foundation]

Postmenopausal lichen planopilaris (PLPP), also known as fibrosing frontotemporal alopecia Kossard (FFAK), is a not uncommon inflammatory scalp disease affecting approximately 5% of patients at specialized hair centers. The overall incidence of sporadic occurrence is believed to be just under 1% in the older, predominantly female, general population. Since the disease is often undiagnosed, it is statistically likely to be underrepresented. It especially occurs in postmenopausal women who are in the 6th and 7th decade of life (90%), but also in about 10% of premenopausal women, and in men it is documented only in isolated cases. The result is a permanent scarring hair loss accentuated at the front hairline with backward movement towards the neck mostly accompanied by a typical loss of the eyebrows. The disease therefore often leads to significant mental distress and social anxiety in those affected. This is the basis for a compelling need to develop evidence-based therapeutic concepts. While numerous retrospective case series have characterized the phenomenology of FFAK very well, to date there are no randomized controlled trials on evidence-based therapy. Here, we present the Homburger Evidence-Oriented Therapy Algorithm, which is oriented along the available case series evidence: It may (1) serve as a therapy guide for practice and (2) can be used as a basis for working out reliable data based on study evidence. The article contains detailed practical information on photo documentation, biopsy and histological processing up to the practical implementation of, for example, intralesional steroid therapy as well as information on selection criteria for suitable systemic therapies.

Lichenoid folliculitis of the scalp in four patients with ichthyosiform skin disorders and cicatricial alopecia

Ichthyosis is a heterogeneous group of inherited skin disorders characterized by a defect of keratinization. Patients diagnosed with lamellar ichthyosis (LI) and some ichthyosiform syndromes, such as the Conradi-Hünermann-Happle syndrome (CHHS), usually present with hair loss. Even though only few dermatologic complaints carry as many emotional overtones as hair loss, there are very few data available in the literature regarding scalp histopathological features in ichthyosis. A better understanding of scalp changes in such context may result in new therapeutic strategies that in turn would enhance patients' self-esteem and quality of life. The aim of this paper is to describe the scalp histopathological findings of four young patients with cicatricial alopecia: three diagnosed as having LI and the fourth with CHHS.

Keratosis pilaris rubra with mucin deposition

Keratosis pilaris (KP) is a benign cutaneous disorder characterized by folliculocentric hyperkeratotic papules most often occurring on the proximal extremities. Erythema is usually limited to perifollicular skin, but when keratosis pilaris presents on a background of confluent erythema, the term keratosis pilaris rubra (KPR) is used. The histological findings associated with KP have not been well described in the literature. Herein, we present a case of a 14-year-old male with a 7-year history of erythema and follicular-based papules over his bilateral cheeks, consistent with KPR. Histological examination revealed abundant mucin, keratotic follicular plugging, and periadnexal lymphocytosis. Our novel finding of abundant dermal mucin expands the histopathologic description of KPR.

Keratosis Pilaris and its Subtypes: Associations, New Molecular and Pharmacologic Etiologies, and Therapeutic Options

Keratosis pilaris is a common skin disorder comprising less common variants and rare subtypes, including keratosis pilaris rubra, erythromelanosis follicularis faciei et colli, and the spectrum of keratosis pilaris atrophicans. Data, and critical analysis of existing data, are lacking, so the etiologies, pathogeneses, disease associations, and treatments of these clinical entities are poorly understood. The present article aims to fill this knowledge gap by reviewing literature in the PubMed, EMBASE, and CINAHL databases and providing a comprehensive, analytical summary of the clinical characteristics and pathophysiology of keratosis pilaris and its subtypes through the lens of disease associations, genetics, and pharmacologic etiologies. Histopathologic, genomic, and epidemiologic evidence points to keratosis pilaris as a primary disorder of the pilosebaceous unit as a result of inherited mutations or acquired disruptions in various biomolecular pathways. Recent data highlight aberrant Ras signaling as an important contributor to the pathophysiology of keratosis pilaris and its subtypes. We also evaluate data on treatments for keratosis pilaris and its subtypes, including topical, systemic, and energy-based therapies. The effectiveness of various types of lasers in treating keratosis pilaris and its subtypes deserves wider recognition.