Primary cicatricial alopecias are characterized by dysregulation of shared gene expression pathways

Quantification of mast cells in central centrifugal cicatricial alopecia

Background

Mast cells (MCs) have recently been implicated in lymphocytic scarring alopecias, which may share a common pathogenesis. MCs in central centrifugal cicatricial alopecia (CCCA) have not been studied.

Objective

We looked for the presence of MCs in CCCA using 2 different stains to see if their numbers correlated with the number of hair follicles, the degree of inflammation and perifollicular fibrosis, disease duration and severity, and patient symptoms.

Methods

We performed a retrospective review of biopsies of patients diagnosed with CCCA, tabulated MC counts and correlated them with histopathologic and clinical findings.

Results

MC counts were significantly greater using immunoperoxidase staining with CD117 than Giemsa stain, and more were present when the isthmus level was included with the infundibulum. MC counts with CD117 immunostain significantly correlated with the degree of inflammation. MC counts with both stains were significantly associated with the degree of fibrosis independently and after controlling for other factors.

Limitations

The study was limited by insufficient tissue remaining in a small number of the transversely cut blocks.

Conclusion

Our findings may have therapeutic implications for CCCA and other types of lymphocytic scarring alopecia.

Updates on disorders in curly hair

Hair disorders, including central centrifugal cicatricial alopecia (CCCA), traction alopecia (TA), and acquired trichorrhexis nodosa (ATN), commonly occur in individuals with curly textured hair. Curly textured hair in individuals of African descent has unique properties and can present diagnostic and therapeutic challenges. CCCA has been linked to uterine leiomyoma and type 2 diabetes mellitus, as well as fibroproliferation. TA often presents with a fringe sign and can arise from high-tension hairstyles presumed to be protective. Trichoscopy is useful in establishing a diagnosis; perifollicular halos are more commonly seen than perifollicular erythema or scale in CCCA. In TA, miniaturized follicles, hair casts, and "flambeau sign" can be seen. Hairstyling practices likely contribute to TA and ATN; however, the data are mixed on the role of chemical relaxers and heat styling in CCCA. Unique considerations in the presentation of frontal fibrosing alopecia in curly textured hair have also been published recently. This review provides a comprehensive, up-to-date summary of these disorders with an emphasis on their unique properties, as well as considerations in hair care for curly textured hair.

Transcriptome analysis of frontal fibrosis alopecia revealed involvement of immune cells and ferroptosis

BACKGROUND

Frontal fibrosis alopecia (FFA) is a primary cicatricial alopecia and has received increasing attention in recent years. However, the pathogenesis of FFA has not been fully elucidated.

METHODS AND RESULTS

Herein, we collected the transcriptome data of scalp lesions of seven patients with FFA and seven healthy controls. The differential expression analysis and weighted gene co-expression network analysis were conducted and we identified 458 differentially expressed genes (DEGs) in two key modules. Later, we performed functional enrichment analysis and functional modules identification, revealing the participation of immune response and fatty acid metabolism. Based on the results, we processed further studies. On the one hand, we analyzed the infiltrating immune cells of FFA through CIBERSORT algorithm, indicating the activation of M1 macrophage and CD8+ T cell. On the other hand, considering lipid metabolism of FFA and oxidative stress of hair follicle cells in alopecia, we explored the potential ferroptosis of FFA. By intersection of DEGs and ferroptosis-related genes from FerrDb database, 19 genes were identified and their expression was validated in an external dataset containing 36 FFA cases and 12 controls. Then, we used LASSO algorithms to construct a four-gene diagnostic model, which achieved an AUC of 0.924 in validation dataset. Additionally, the immune cells were found to be related to ferroptosis in FFA.

CONCLUSION

Taken together, this study contributed to reveal the molecular mechanisms of FFA and is expected to inspire future research on treatment.

Clinicopathological characteristics of fibrosing alopecia in a pattern distribution: a single-center, retrospective study

BACKGROUND

Fibrosing alopecia in a pattern distribution (FAPD) is a distinct entity of primary cicatricial alopecia (PCA), mimicking diffuse hair loss of androgenetic alopecia (AGA) with trichoscopic and histopathologic features of both AGA and lichen planopilaris (LPP).

METHODS

Clinical, demographic, and histopathological data of 20 FAPD patients were retrospectively collected.

RESULTS

All patients presented with female pattern hair loss with a median Sinclair grade of 3. Trichoscopic findings revealed hair diameter variability (20/20), perifollicular erythema (mild 7/20, moderate 11/20, severe 2/20), peripilar casts (none 2/20, mild 12/20, moderate 5/20, severe 1/20), and loss of follicular ostia (+12/20, ±7/20, -1/20). Histopathologic examination revealed perifollicular lymphocytic infiltration at the infundibulum or isthmus level and an increase of vellus-like hairs. All cases showed interface dermatitis with concentric perifollicular lamellar fibrosis and follicular scars. Infundibular or isthmic infiltration of mast cells was found.

CONCLUSIONS

The uniqueness of our study lies in perifollicular mast cells and discovering that the young population is at higher risk than previously thought. Clinicopathological features of FAPD were identified, filling the void of much-needed details for FAPD diagnosis tailored to the Chinese population.

mTOR signaling in hair follicle and hair diseases: recent progress

Mammalian target of rapamycin (mTOR) signaling pathway is a major regulator of cell proliferation and metabolism, playing significant roles in proliferation, apoptosis, inflammation, and illness. More and more evidences showed that the mTOR signaling pathway affects hair follicle circulation and maintains the stability of hair follicle stem cells. mTOR signaling may be a critical cog in Vitamin D receptor (VDR) deficiency-mediated hair follicle damage and degeneration and related alopecia disorders. This review examines the function of mTOR signaling in hair follicles and hair diseases, and talks about the underlying molecular mechanisms that mTOR signaling regulates.

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.

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.