The Alopecia Areata Consensus of Experts (ACE) study part II: Results of an international expert opinion on diagnosis and laboratory evaluation for alopecia areata

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences

Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment loss, respectively. In AA, inflammatory cell infiltrates are in the deep reticular dermis close to the hair bulb (swarm of bees), whereas in vitiligo the inflammatory infiltrates are in the epidermis and papillary dermis. Immune privilege collapse has been extensively investigated in AA pathogenesis, including the suppression of immunomodulatory factors (e.g., transforming growth factor-β (TGF-β), programmed death-ligand 1 (PDL1), interleukin-10 (IL-10), α-melanocyte-stimulating hormone (α-MSH), and macrophage migration inhibitory factor (MIF)) and enhanced expression of the major histocompatibility complex (MHC) throughout hair follicles. However, immune privilege collapse in vitiligo remains less explored. Both AA and vitiligo are autoimmune diseases that share commonalities in pathogenesis, including the involvement of plasmacytoid dendritic cells (and interferon-α (IFN- α) signaling pathways) and cytotoxic CD8+ T lymphocytes (and activated IFN-γ signaling pathways). Blood chemokine C-X-C motif ligand 9 (CXCL9) and CXCL10 are elevated in both diseases. Common factors that contribute to AA and vitiligo include oxidative stress, autophagy, type 2 cytokines, and the Wnt/β-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

Current Diagnostic and Therapeutic Practices in Alopecia Areata in Two Mediterranean Countries: A Survey-Based Study

INTRODUCTION

Alopecia areata (AA) affects approximately 2% of the general population and is associated with significant psychosocial morbidity and poor health-related quality of life. Despite the high incidence of the disease the available clinical practice guidelines to help clinicians and improve patients' care are very poor and of a low methodological quality, as compared to other high-burden dermatoses. The aim of this survey is to capture the current clinical practice in AA management, as performed by dermatologists, in two Mediterranean countries to identify potential disparities and gaps in diagnosis and treatment.

METHODS

A 50-item questionnaire was created in the English language and then translated into Greek and Italian language and sent to the Greek and Italian dermatologists via email.

RESULTS

A total of 490 dermatologists from Italy and 234 from Greece participated in the survey. The diagnosis of AA is usually based on history and clinical examination, supported by trichoscopy. The rate of use of severity scores and scales to evaluate impact on quality of life by dermatologists was low. Treatment of patchy AA, in both adult and pediatric populations, is based on use of topical steroids as first-line treatment. Results on special site involvement (eyebrows, beard, and ophiasis), chronic cases, and the pediatric population highlight extreme heterogeneity in treatment approach.

CONCLUSIONS

Our results highlight that management of AA, in terms of diagnosis and treatment, is still challenging.

The Alopecia Areata Severity and Morbidity Index (ASAMI) Study: Results From a Global Expert Consensus Exercise on Determinants of Alopecia Areata Severity

Importance

Current measures of alopecia areata (AA) severity, such as the Severity of Alopecia Tool score, do not adequately capture overall disease impact.

Objective

To explore factors associated with AA severity beyond scalp hair loss, and to support the development of the Alopecia Areata Severity and Morbidity Index (ASAMI).

Evidence Review

A total of 74 hair and scalp disorder specialists from multiple continents were invited to participate in an eDelphi project consisting of 3 survey rounds. The first 2 sessions took place via a text-based web application following the Delphi study design. The final round took place virtually among participants via video conferencing software on April 30, 2022.

Findings

Of all invited experts, 64 completed the first survey round (global representation: Africa [4.7%], Asia [9.4%], Australia [14.1%], Europe [43.8%], North America [23.4%], and South America [4.7%]; health care setting: public [20.3%], private [28.1%], and both [51.6%]). A total of 58 specialists completed the second round, and 42 participated in the final video conference meeting. Overall, consensus was achieved in 96 of 107 questions. Several factors, independent of the Severity of Alopecia Tool score, were identified as potentially worsening AA severity outcomes. These factors included a disease duration of 12 months or more, 3 or more relapses, inadequate response to topical or systemic treatments, rapid disease progression, difficulty in cosmetically concealing hair loss, facial hair involvement (eyebrows, eyelashes, and/or beard), nail involvement, impaired quality of life, and a history of anxiety, depression, or suicidal ideation due to or exacerbated by AA. Consensus was reached that the Alopecia Areata Investigator Global Assessment scale adequately classified the severity of scalp hair loss.

Conclusions and Relevance

This eDelphi survey study, with consensus among global experts, identified various determinants of AA severity, encompassing not only scalp hair loss but also other outcomes. These findings are expected to facilitate the development of a multicomponent severity tool that endeavors to competently measure disease impact. The findings are also anticipated to aid in identifying candidates for current and emerging systemic treatments. Future research must incorporate the perspectives of patients and the public to assign weight to the domains recognized in this project as associated with AA severity.

Epidemiology of alopecia areata and population-wide comorbidities in Germany: analysis of longitudinal claims data

BACKGROUND

Alopecia areata (AA) is a chronic, immune-mediated disease characterized by acute-onset hair loss. The hair loss can range from small, circumscribed hairless areas on the scalp to complete loss of hair on the head and body hair. However, data on the epidemiology of AA are limited. Current evaluations are lacking in Germany. The aim of this study was to evaluate the epidemiology and comorbidity of AA in Germany based on claims data.

METHODS

A representative 40% sample of all adults who were insured with a German statutory health insurance company (DAK-Gesundheit) between 2016 and 2020 was evaluated (n = 2.88 million). Based on at least one relevant outpatient or inpatient diagnosis of International Classification of Diseases (ICD)-10 L63, the annual AA prevalence and incidence (ICD-10 L63) were calculated for 2016 to 2020. Different case definitions were used for diagnosis validation. In addition, the occurrence of comorbidities in patients with AA was investigated.

RESULTS

In 2020, AA prevalence was 210 cases per 100 000 and incidence 72 cases per 100 000. Compared with persons without AA, those with AA significantly more often had atopic dermatitis [rate ratio (RR) 2.9], pruritus (RR 2.7), lupus erythematosus (RR 2.4), urticaria (RR 2.3) and psoriasis (RR 2.2). Women were affected slightly more often than men (0.2% vs. 0.1%). On a regional level, higher prevalence and incidence rates were found in Brandenburg (prevalence 332 cases per 100 000; incidence 116 cases per 100 000), Hesse (prevalence 344 cases per 100 000; incidence 124 cases per 100 000) and Mecklenburg-Western Pomerania (prevalence 303 cases per 100 000; incidence 111 per 100 000).

CONCLUSIONS

AA is a common immune-mediated skin condition with marked regional variations in Germany. For a complete understanding of epidemiology, complementary population-based studies including clinical characteristics of AA are useful.

Alopecia areata: What's new in the diagnosis and treatment with JAK inhibitors?

Alopecia areata (AA) affects individuals of all ages and is intractable in severe relapsing cases. Dermatologists and other healthcare providers should consider AA in the medical context and prioritize treatment. Several randomized controlled clinical studies on Janus kinase (JAK) inhibitors with different specificities for the treatment of AA are ongoing. These studies have encouraged us to appreciate the importance of a definitive diagnosis and accurate evaluation of AA before and during treatment. Following our previous review article in 2017, here we provide the second part of this two-review series on the recent progress in the multidisciplinary approaches to AA from more than 1800 articles published between July 2016 and December 2022. This review focuses on the evaluation, diagnosis, and treatment of AA. We also provide the latest information on the safety and efficacy of JAK inhibitors for the treatment of AA and describe their mechanisms of action.

Machine learning application in autoimmune diseases: State of art and future prospectives

Autoimmune diseases are a group of disorders resulting from an alteration of immune tolerance, characterized by the formation of autoantibodies and the consequent development of heterogeneous clinical manifestations. Diagnosing autoimmune diseases is often complicated, and the available prognostic tools are limited. Machine learning allows us to analyze large amounts of data and carry out complex calculations quickly and with minimal effort. In this work, we examine the literature focusing on the use of machine learning in the field of the main systemic (systemic lupus erythematosus and rheumatoid arthritis) and organ-specific autoimmune diseases (type 1 diabetes mellitus, autoimmune thyroid, gastrointestinal, and skin diseases). From our analysis, interesting applications of machine learning emerged for developing algorithms useful in the early diagnosis of disease or prognostic models (risk of complications, therapeutic response). Subsequent studies and the creation of increasingly rich databases to be supplied to the algorithms will eventually guide the clinician in the diagnosis, allowing intervention when the pathology is still in an early stage and immediately directing towards a correct therapeutic approach.

Inhibition of T-cell activity in alopecia areata: recent developments and new directions

Alopecia areata (AA) is an autoimmune disease that has a complex underlying immunopathogenesis characterized by nonscarring hair loss ranging from small bald patches to complete loss of scalp, face, and/or body hair. Although the etiopathogenesis of AA has not yet been fully characterized, immune privilege collapse at the hair follicle (HF) followed by T-cell receptor recognition of exposed HF autoantigens by autoreactive cytotoxic CD8+ T cells is now understood to play a central role. Few treatment options are available, with the Janus kinase (JAK) 1/2 inhibitor baricitinib (2022) and the selective JAK3/tyrosine kinase expressed in hepatocellular carcinoma (TEC) inhibitor ritlecitinib (2023) being the only US Food and Drug Administration-approved systemic medications thus far for severe AA. Several other treatments are used off-label with limited efficacy and/or suboptimal safety and tolerability. With an increased understanding of the T-cell-mediated autoimmune and inflammatory pathogenesis of AA, additional therapeutic pathways beyond JAK inhibition are currently under investigation for the development of AA therapies. This narrative review presents a detailed overview about the role of T cells and T-cell-signaling pathways in the pathogenesis of AA, with a focus on those pathways targeted by drugs in clinical development for the treatment of AA. A detailed summary of new drugs targeting these pathways with expert commentary on future directions for AA drug development and the importance of targeting multiple T-cell-signaling pathways is also provided in this review.

Diagnosis and Management of Alopecia Areata: A Saudi Expert Consensus Statement (2023)

Alopecia areata (AA) is a complex autoimmune disease manifesting as a chronic inflammatory disease characterized by non-scarring patches of hair loss over the face, scalp, and body. Several treatments have been proposed for AA, but none are curative nor achieve a state of remission. The present consensus statement aims to present the evidence- and experience-based recommendations on the diagnosis and management of AA in Saudi Arabia. The Ministry of Health in Saudi Arabia has opted to initiate a meeting of a multidisciplinary group to discuss and concede on this topic. Eight dermatology experts and clinical pharmacists convened in eight consensus meetings. All content presented in this document was agreed upon by this working group, including diagnosis and severity assessment, prognostic indicators, and therapeutic options for AA. Special consideration was given to special patient populations including pediatric patients and patients with less frequent presentations of AA. Updates of the current recommendations will take place as new evidence evolves in the treatment of AA.

Beyond health-related quality of life: initial psychometric validation of a new scale for addressing the gap in assessing the full range of alopecia areata psychosocial burden

BACKGROUND

Patients with alopecia areata (AA) report a broad range of psychosocial outcomes beyond those assessed in existing health-related quality of life measures. Yet, to date, no psychometrically validated scale based on patient-reported outcomes (PROs) appears to exist to comprehensively measure these AA-specific psychosocial outcomes.

OBJECTIVES

The objective of this study was to develop such a scale, the Scale of Alopecia Areata Distress (SAAD), and to provide its initial validation evidence.

METHODS

Using existing qualitative research on PROs for patients with AA, a pool of 144 items was generated and subsequently reviewed for relevance, redundancy, clarity and comprehensiveness by subject matter experts in AA psychosocial impacts and the research team. This review resulted in a reduced pool of 122 items, which was then administered to adult patients with AA residing in the USA. Exploratory Factor Analysis using Principal Axis Factoring extraction with oblique rotation identified the SAAD's underlying factor structure. To reduce the SAAD item length, additional item-reduction strategies were used.

RESULTS

There were 392 participants who responded to the 122 items, each with four or fewer missing item responses. Three iterations of the data analysis plan resulted in a 41-item SAAD with seven underlying factors of psychosocial impact: Emotional and Cognitive Functioning, Romantic Relationships, Family Relationships, Primary Life Responsibilities, Non-Primary Life Responsibility Activities, Stigma, and Self-Perception Change. Each factor demonstrated acceptable to high levels of internal consistency reliability.

CONCLUSIONS

Initial validation evidence of the SAAD-41 scale supports its potential as a comprehensive measure of AA-related psychosocial distress for US-based adults. Further scale validation is needed.

Guidelines for the Management of Patients with Alopecia Areata in Korea: Part I Topical and Device-based Treatment

BACKGROUND

Alopecia areata (AA) is a chronic disease with an unpredictable disease course and severe psychological impact.

OBJECTIVE

To provide evidence- and consensus-based insights regarding the treatment of patients with AA in Korea.

METHODS

We searched for relevant studies on the topical and device-based treatment of AA in the literature from inception until May 2021. Evidence-based recommendations were also prepared. The evidence for each statement was graded and classified according to the strength of the recommendations. Hair experts from the Korean Hair Research Society (KHRS) voted on the statements, and an agreement of 75% or greater was considered as consensus.

RESULTS

Currently, there remains a scarcity of topical treatments, which is supported by robust evidence from a number of high-quality randomized controlled trials. Current evidence supports the efficacy of topical corticosteroids, corticosteroid intralesional injection, and contact immunotherapy in AA patients. Topical corticosteroids and contact immunotherapy are recommended for pediatric AA. A consensus was achieved in 6 out of 14 (42.8%), and 1 out of 5 (20.0%) statements pertaining to topical and device-based treatments in AA, respectively. The expert consensus was from a single country, and the study may not cover all the treatments used.

CONCLUSION

The present study provides up-to-date, evidence-based treatment guidelines for AA based on the consensus reached among experts after considering regional healthcare circumstances, adding diversity to the previous guidelines.

Guidelines for the Management of Patients with Alopecia Areata in Korea: Part II Systemic Treatment

BACKGROUND

Alopecia areata (AA) is a chronic disease with an unpredictable course and can have a severe psychological impact on an individual.

OBJECTIVE

To provide evidence and consensus-based statements regarding the treatment of patients with AA in Korea.

METHODS

We searched for relevant studies from inception to May 2021 regarding the systemic treatment of AA. Evidence-based recommendations were also prepared. The evidence for each statement was graded and classified according to the strength of the recommendations. Hair experts from the Korean Hair Research Society (KHRS) voted on the statement, and an agreement of 75% or greater was considered as having reached consensus.

RESULTS

Current evidence supports the efficacy of systemic corticosteroids, oral cyclosporine monotherapy or combination with systemic corticosteroids, and oral Janus kinase inhibitors in severe AA patients. Systemic steroids may be considered for pediatric patients with severe AA. A consensus was achieved in three out of nine (33.3%), and one out of three (33.3%) statements pertaining to systemic treatment in adult and pediatric AA, respectively.

CONCLUSION

The present study produced up-to-date, evidence-based treatment guidelines for AA associated with the consensus obtained by experts based on the Korean healthcare system.

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.

Viral-Induced Rapidly Progressive Alopecia Universalis: A Case Report and Literature Review

Alopecia areata is a common autoimmune condition that causes a non-scarring form of hair loss. It is associated with several viruses and diseases. One of the viruses that have been linked to alopecia areata is the coronavirus disease of 2019 (COVID-19). It was found to cause the onset, aggravation, or recurrence of alopecia areata in previously infected patients. We report the case of a 20-year-old woman who was medically free and presented with the severe and progressive onset of alopecia areata after one month of contracting COVID-19. This study aimed to explore the literature on COVID-19-associated severe onset alopecia areata in terms of timeline and clinical presentation.

Involvement of ILC1-like innate lymphocytes in human autoimmunity, lessons from alopecia areata

Here, we have explored the involvement of innate lymphoid cells-type 1 (ILC1) in the pathogenesis of alopecia areata (AA), because we found them to be significantly increased around lesional and non-lesional HFs of AA patients. To further explore these unexpected findings, we first co-cultured autologous circulating ILC1-like cells (ILC1lc) with healthy, but stressed, organ-cultured human scalp hair follicles (HFs). ILClc induced all hallmarks of AA ex vivo: they significantly promoted premature, apoptosis-driven HF regression (catagen), HF cytotoxicity/dystrophy, and most important for AA pathogenesis, the collapse of the HFs physiological immune privilege. NKG2D-blocking or IFNγ-neutralizing antibodies antagonized this. In vivo, intradermal injection of autologous activated, NKG2D+/IFNγ-secreting ILC1lc into healthy human scalp skin xenotransplanted onto SCID/beige mice sufficed to rapidly induce characteristic AA lesions. This provides the first evidence that ILC1lc, which are positive for the ILC1 phenotype and negative for the classical NK markers, suffice to induce AA in previously healthy human HFs ex vivo and in vivo, and further questions the conventional wisdom that AA is always an autoantigen-dependent, CD8 +T cell-driven autoimmune disease.

Global Guidelines in Dermatology Mapping Project (GUIDEMAP): a systematic review of alopecia areata clinical practice guidelines

INTRODUCTION

Alopecia areata (AA) is a nonscarring alopecia with an estimated global prevalence of 2% and limited data on the efficacy of current treatment. Clinical practice guidelines (CPGs) provide recommendations based on best available evidence. It is unclear how many AA CPGs are available globally.

AIM

To systematically search for and identify CPGs on AA and to critically appraise their quality using validated tools.

METHODS

We performed a literature search to identify CPGs published between October 2014 and April 2021, using the following databases: MEDLINE, Embase, National Institute for Health and Care Excellence (NICE), Guidelines International Network, Emergency Care Research Institute guidelines trust, Australian CPGs, Turning Research Into Practice database and DynaMed. The systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. Three critical appraisal tools were used: Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument, Lenzer's red flags and United States Institute of Medicine's (IOM) criteria of trustworthiness.

RESULTS

In total, six AA CPGs from seven manuscripts (one CPG was in two parts published in separate papers) were included. The majority (four of six) of the CPGs focused on treatment. Four CPGs (total of five papers) were in English and two CPGs were only available in the original language (one Russian and one Japanese). All AA CPGs demonstrated low quality in several domains in the AGREE II appraisal, including stakeholder involvement and applicability, with the latter being deemed the worst domain for all CPGs, with an average of 29%. The mean (SD) number of Lenzer's red flags for the included CPGs was 3.4 (1.5) out of a total of 8 possible red flags, while the IOM criteria showed 1.6 (0.8) 'fully met' criteria and 3.1 (1.2) 'not met' out of a total of 9 criteria.

CONCLUSION

We found a limited number of AA CPGs, all of which had significant methodological deficiencies. We encourage guideline development groups to use validated checklists/tools to develop reliable and trustworthy CPGs.

The burden of alopecia areata: A scoping review focusing on quality of life, mental health and work productivity

Alopecia areata (AA) is a common inflammatory autoimmune disease of the hair which can have a significant negative impact on quality of life (QoL), mental health and productivity. The aim of this scoping review is to elucidate the burden of AA focusing on these three realms. Inclusion criteria included all original manuscripts with no restriction on study type or statistical method written in English (or having an English abstract). For QoL 40 articles were included, 85 for psychiatric comorbidities, and 9 for work/school absenteeism/presenteeism mostly consisting of cross-sectional and observational cohort studies. QoL impairment was detected in over 75% of patients and up to one-third reported extremely severe QoL impairments. Specific QoL dimensions with the greatest impact were embarrassment, social functioning, as well as shopping and/or housework. Cross-sectional studies assessing the psychological burden of adult patients with AA found that the presence of signs of anxiety and/or depression ranged from 30% to 68% and affected all age groups. Rates of work absenteeism and unemployment were significantly higher in AA patients compared to healthy controls. Up to 62% reported making major life decisions including relationships, education and career based on their AA. Additionally, the extensive camouflage techniques and time lost from work led to a strong financial burden for patients and the numerous physician visits added to the healthcare costs. The overall impact of AA stretches much further than simply being an aesthetic concern and can negatively impact every part of an individual's life. An individualized approach and effective treatments will help reduce the psychosocial consequences and distress and return patients to their normal state of health.

Exploring the overlap between alopecia areata and major depressive disorder: Epidemiological and genetic perspectives

BACKGROUND

Research suggests that Alopecia areata (AA) and Major Depressive Disorder (MDD) show substantial comorbidity. To date, no study has investigated the hypothesis that this is attributable to shared genetic aetiology.

OBJECTIVES

To investigate AA-MDD comorbidity on the epidemiological and molecular genetic levels.

METHODS

First, epidemiological analyses were performed using data from a cohort of adult German health insurance beneficiaries (n = 1.855 million) to determine the population-based prevalence of AA-MDD comorbidity. Second, analyses were performed to determine the prevalence of MDD in a clinical AA case-control sample with data on psychiatric phenotypes, stratifying for demographic factors to identify possible contributing factors to AA-MDD comorbidity. Third, the genetic overlap between AA and MDD was investigated using a polygenic risk score (PRS) approach and linkage disequilibrium score (LDSC) regression. For PRS, summary statistics from a large MDD GWAS meta-analysis (PGC-MD2) were used as the training sample, while a Central European AA cohort, including the above-mentioned AA patients, and an independent replication US-AA cohort were used as target samples. LDSC was performed using summary statistics of PGC-MD2 and the largest AA meta-analysis to date.

RESULTS

High levels of AA-MDD comorbidity were reported in the population-based (MDD in 24% of AA patients), and clinical samples (MDD in 44% of AA patients). MDD-PRS explained a modest proportion of variance in AA case-control status (R²  = 1%). This signal was limited to the major histocompatibility complex (MHC) region on chromosome 6. LDSC regression (excluding MHC) revealed no significant genetic correlation between AA and MDD.

CONCLUSIONS

As in previous research, AA patients showed an increased prevalence of MDD. The present analyses suggest that genetic overlap may be confined to the MHC region, which is implicated in immune function. More detailed investigation is required to refine understanding of how the MHC is involved in the development of AA and MDD comorbidity.

Topical SCD-153, a 4-methyl itaconate prodrug, for the treatment of alopecia areata

Alopecia areata is a chronic hair loss disorder that involves autoimmune disruption of hair follicles by CD8⁺  T cells. Most patients present with patchy hair loss on the scalp that improves spontaneously or with topical and intralesional steroids, topical minoxidil, or topical immunotherapy. However, recurrence of hair loss is common, and patients with extensive disease may require treatment with oral corticosteroids or oral Janus kinase (JAK) inhibitors, both of which may cause systemic toxicities with long-term use. Itaconate is an endogenous molecule synthesized in macrophages that exerts anti-inflammatory effects. To investigate the use of itaconate derivatives for treating alopecia areata, we designed a prodrug of 4-methyl itaconate (4-MI), termed SCD-153, with increased lipophilicity compared to 4-MI (CLogP 1.159 vs. 0.1442) to enhance skin and cell penetration. Topical SCD-153 formed 4-MI upon penetrating the stratum corneum in C57BL/6 mice and showed low systemic absorption. When added to human epidermal keratinocytes stimulated with polyinosinic-polycytidylic acid (poly I:C) or interferon (IFN)γ, SCD-153 significantly attenuated poly I:C-induced interleukin (IL)-6, Toll-like receptor 3, IL-1β, and IFNβ expression, as well as IFNγ-induced IL-6 expression. Topical application of SCD-153 to C57BL/6 mice in the resting (telogen) phase of the hair cycle induced significant hair growth that was statistically superior to vehicle (dimethyl sulfoxide), the less cell-permeable itaconate analogues 4-MI and dimethyl itaconate, and the JAK inhibitor tofacitinib. Our results suggest that SCD-153 is a promising topical candidate for treating alopecia areata.

Novel potential therapeutic targets of alopecia areata

Alopecia areata (AA) is a non-scarring hair loss disorder caused by autoimmunity. The immune collapse of the hair follicle, where interferon-gamma (IFN-γ) and CD8+ T cells accumulate, is a key factor in AA. However, the exact functional mechanism remains unclear. Therefore, AA treatment has poor efficacy maintenance and high relapse rate after drug withdrawal. Recent studies show that immune-related cells and molecules affect AA. These cells communicate through autocrine and paracrine signals. Various cytokines, chemokines and growth factors mediate this crosstalk. In addition, adipose-derived stem cells (ADSCs), gut microbiota, hair follicle melanocytes, non-coding RNAs and specific regulatory factors have crucial roles in intercellular communication without a clear cause, suggesting potential new targets for AA therapy. This review discusses the latest research on the possible pathogenesis and therapeutic targets of AA.

How Our Microbiome Influences the Pathogenesis of Alopecia Areata

Alopecia areata is a multifactorial autoimmune-based disease with a complex pathogenesis. As in all autoimmune diseases, genetic predisposition is key. The collapse of the immune privilege of the hair follicle leading to scalp loss is a major pathogenic event in alopecia areata. The microbiota considered a bacterial ecosystem located in a specific area of the human body could somehow influence the pathogenesis of alopecia areata, as it occurs in other autoimmune diseases. Moreover, the Next Generation Sequencing of the 16S rRNA bacterial gene and the metagenomic methodology have provided an excellent characterization of the microbiota. The aim of this narrative review is to examine the published literature on the cutaneous and intestinal microbiota in alopecia areata to be able to establish a pathogenic link. In this review, we summarize the influence of the microbiota on the development of alopecia areata. We first introduce the general pathogenic mechanisms that cause alopecia areata to understand the influence that the microbiota may exert and then we summarize the studies that have been carried out on what type of gut and skin microbiota is found in patients with this disease.

Alopecia areata - Current understanding and management

Alopecia areata (AA) is a chronic, immune-mediated disease characterized by acute or chronic non-scarring hair loss, with a heterogeneity in clinical manifestations ranging from patchy hair loss to complete scalp and body hair loss. An overview of the up-to-date pathophysiology and the underlying signaling pathways involved in AA together with diagnostic and therapeutic recommendations will be provided. Current treatments, including topical, systemic and injectable interventions show varying response and frequent relapses reflecting the unmet clinical need. Thus, the new emerging concepts and therapeutic approaches, including Janus kinase inhibitors are eagerly awaited. Traditional and emerging therapies of AA will be discussed, in order to provide physicians with guidance for AA management. Since the latter is so challenging and often tends to take a chronic course, it can have an enormous psychosocial burden on patients, compromising their quality of life and often causing depression and anxiety. Therefore, the psychosocial aspects of the disease need to be evaluated and addressed, in order to implement appropriate psychological support when needed.

Ritlecitinib: an investigational drug for the treatment of moderate to severe alopecia areata

INTRODUCTION

Alopecia areata (AA) is an inflammatory and autoimmune form of hair loss, which can present with one patch of hair loss, but in more extreme cases can lead to total body hair loss. There are limited therapeutic options and no cure, but medication can sometimes induce sustained remission. Disease control cannot be guaranteed; even those who regrow all hair on treatment can experience relapse. There are no FDA approved systemic treatments; therefore, an unmet need for safe, and effective treatments exists. Few treatments have been evaluated by randomized controlled trials. Case reports and series indicate oral Janus Kinase (JAK) inhibitors as a potential therapy. Ritlecitinib is a novel oral JAK3-selective inhibitor being investigated as an AA treatment.

AREAS COVERED

This article introduces ritlecitinib as treatment for AA and considers the mechanism of action, pharmacodynamics, pharmacokinetics, clinical efficacy, and safety [reporting data from a 24-week, phase 2a double-blinded placebo-controlled trial of ritlecitinib in patients with AA who have more than 50% scalp hair loss].

EXPERT OPINION

Ritlecitinib offers a novel mode of action, rapid onset, and the capacity for a superior safety profile over other JAK inhibitors. If approved, ritlecitinib will be widely prescribed by physicians overseeing the more severe AA patients for the foreseeable future. As JAK inhibitors regulate the hair growth cycle and have anti-inflammatory effects, the implementation of ritlecitinib in hair loss disorders other than AA, may prove beneficial.

Learning from disease registries during a pandemic: Moving toward an international federation of patient registries

High-quality dermatology patient registries often require considerable time to develop and produce meaningful data. Development time is influenced by registry complexity and regulatory hurdles that vary significantly nationally and institutionally. The rapid emergence of the coronavirus disease 2019 (COVID-19) global pandemic has challenged health services in an unprecedented manner. Mobilization of the dermatology community in response has included rapid development and deployment of multiple, partially harmonized, international patient registries, reinventing established patient registry timelines. Partnership with patient organizations has demonstrated the critical nature of inclusive patient involvement. This global effort has demonstrated the value, capacity, and necessity for the dermatology community to adopt a more cohesive approach to patient registry development and data sharing that can lead to myriad benefits. These include improved utilization of limited resources, increased data interoperability, improved ability to rapidly collect meaningful data, and shortened response times to generate real-world evidence. We call on the global dermatology community to support the development of an international federation of patient registries to consolidate and operationalize the lessons learned during this pandemic. This will provide an enduring means of applying this knowledge to the maintenance and development of sustainable, coherent, and impactful patient registries of benefit now and in the future.

Alopecias in humans: biology, pathomechanisms and emerging therapies

BACKGROUND

The hair follicle is a complete mini-organ with a complex biology. Recent discoveries have shed light on the pathogenesis and genetic basis of a number of hair loss conditions, offering novel treatment alternatives.

OBJECTIVE

To explore the biology and physiology of hair growth, the pathomechanism behind alopecias and emerging therapies.

CONCLUSION AND CLINICAL IMPORTANCE

Hair growth is influenced by numerous physiological moderators. Greater understanding of the biology and physiology of the hair follicle and the pathomechanisms of hair disease facilitates development of targeted treatments. Sublingual minoxidil is a promising therapy in humans where optimised drug delivery enhances efficacy and reduces systemic adverse effects. Janice kinase inhibitors, which disrupt the inflammatory cascade, help maintain the hair follicle, preserve immune privilege, and regrow hair in alopecia areata. As the pathomechanisms of other forms of alopecia become better understood, new targeted therapies with greater efficacy will emerge.

Classification Framework for Healthy Hairs and Alopecia Areata: A Machine Learning (ML) Approach

Alopecia areata is defined as an autoimmune disorder that results in hair loss. The latest worldwide statistics have exhibited that alopecia areata has a prevalence of 1 in 1000 and has an incidence of 2%. Machine learning techniques have demonstrated potential in different areas of dermatology and may play a significant role in classifying alopecia areata for better prediction and diagnosis. We propose a framework pertaining to the classification of healthy hairs and alopecia areata. We used 200 images of healthy hairs from the Figaro1k dataset and 68 hair images of alopecia areata from the Dermnet dataset to undergo image preprocessing including enhancement and segmentation. This was followed by feature extraction including texture, shape, and color. Two classification techniques, i.e., support vector machine (SVM) and k-nearest neighbor (KNN), are then applied to train a machine learning model with 70% of the images. The remaining image set was used for the testing phase. With a 10-fold cross-validation, the reported accuracies of SVM and KNN are 91.4% and 88.9%, respectively. Paired sample T-test showed significant differences between the two accuracies with a p < 0.001. SVM generated higher accuracy (91.4%) as compared to KNN (88.9%). The findings of our study demonstrate potential for better prediction in the field of dermatology.

Measuring Patient Quality of Life Following Treatment for Alopecia

Alopecia is a challenging problem for both physicians and patients in terms of diagnosis and treatment. Alopecia usually has negative effects on patients' emotional and psychological well-being. Several studies have examined the effect of alopecia on patients' health-related quality of life (HRQoL) and have consistently reported poor scores. However, deeper insight into the impact of alopecia on affected individuals and its measurement using HRQoL questionnaires is lacking in the literature. In this article, the methods for measuring the HRQoL of patients with alopecia were comprehensively reviewed. Their applications and limitations were also discussed.