Phase 2a randomized clinical trial of dupilumab (anti-IL-4Rα) for alopecia areata patients

A Review of JAK Inhibitors for Treatment of Alopecia Areata in the Military Health Care System

INTRODUCTION

Alopecia areata (AA) is a disease that manifests as patchy hair loss on the scalp and other parts of the body; severe disease may result in disfigurement, functional impairment, and significant psychological distress. This condition is understood to be caused by autoimmunity to the hair follicle and subsequent arrest of hair growth. New medications, baricitinib and ritlecitinib, belong to the Janus kinase (JAK) inhibitor family and are among the first FDA-approved treatments for severe AA. In this manuscript, we aim to answer the question: What treatment options exist for AA in the military health care system (MHS)? In doing so, we review the pathogenesis, physical and psychosocial impact of AA, conventional treatment of AA, and the efficacy and safety of baricitinib and ritlecitinib.

METHODS

A literature search was performed using PubMed, Embase, and Ovid for the history and pathogenesis of AA, psychosocial impact of disease, functional impairments, and current treatments. Keywords "alopecia areata," "current therapy for alopecia areata," "pathogenesis alopecia areata," "baricitinib," "ritlecitinib," "JAK inhibitor alopecia," "JAK inhibitor safety," "baricitinib efficacy," "alopecia eyelash," "alopecia nails," and "psychosocial impact of alopecia" were used for the search. The TRICARE manual was searched for guidelines applicable to the treatment of AA, DoD Instruction 6130.03 Volume 2 for medical standards for military service, and the U.S. Central Command Modification 15 for fitness of deployment to Central Command area of operations.

RESULTS

Traditional treatments such as intralesional steroids may be effective for some patients, but difficulty lies in controlling extensive or refractory disease. Janus kinase inhibitors, baricitinib and ritlecitinib, are found effective at improving severe refractory disease; baricitinib induced hair regrowth in 32.6% more patients than placebo, and ritlecitinib was found to be superior to placebo by at least 24%. Currently, there is no coverage for therapeutic treatment of hair growth in the MHS. Additionally, military members are disqualified for continued service if they require immunomodulator medications such as baricitinib and ritlecitinib. Those on immunomodulators are unable to deploy worldwide.

CONCLUSIONS

Baricitinib and ritlecitinib are effective treatments for widespread, progressive, and refractory AA. Although JAK inhibitors demonstrate improved effectiveness compared to non-immunomodulator treatments, their use in the MHS for this purpose is limited.

Type-2 immunity associated with type-1 related skin inflammatory diseases: friend or foe?

Chronic inflammatory skin diseases are multifactorial diseases that combine genetic predisposition, environmental triggers, and metabolic disturbances associated with abnormal immune responses. From an immunological perspective, the better understanding of their physiopathology has demonstrated a large complex network of immune cell subsets and related cytokines that interact with both epidermal and dermal cells. For example, in type-1-associated diseases such as alopecia areata, vitiligo, and localized scleroderma, recent evidence suggests the presence of a type-2 inflammation that is well known in atopic dermatitis. Whether this type-2 immune response has a protective or detrimental impact on the development and chronicity of these diseases remains to be fully elucidated, highlighting the need to better understand its involvement for the management of patients. This mini-review explores recent insights regarding the potential role of type-2-related immunity in alopecia areata, vitiligo, and localized scleroderma.

Novel investigational drugs for alopecia areata and future perspectives

INTRODUCTION

Alopecia areata (AA) is an immune-mediated disease that causes non-scarring hair loss. While acute, solitary patches often spontaneously remit, developing secondary patches or failure of the disease to resolve within 6-12 months predicts a poor prognosis, with an increased risk of alopecia totalis or universalis. Chronic AA increases the risk of depression and suicidality and reduces quality of life. Treatment options for chronic or acute diffuse AA were previously limited to corticosteroids and traditional immunomodulators. Two Janus Kinase (JAK) inhibitors are now approved for the treatment of chronic AA.

AREAS COVERED

The results of landmark phase 3 trials for three JAK inhibitors, baricitinib, ritlecitinib, and deuruxolitinib are discussed. Evidence for other JAK inhibitors, biologics, and phosphodiesterase-4 inhibitors are also presented. Therapies currently undergoing clinical trials are listed.

EXPERT OPINION

JAK inhibitors are a safe and efficacious treatment of moderate-to-severe AA. Early intervention, regardless of severity, allows for improved treatment efficacy. It is uncertain how long patients should remain on JAK inhibitors; discontinuation often leads to relapse. A black-box warning for JAK inhibitors was extrapolated from safety data in a rheumatoid arthritis cohort; recent meta-analyses of JAK inhibitors used in dermatology cohorts do not demonstrate the same risk profile.

Genetic links between atopy, allergy, and alopecia areata: insights from a Mendelian randomization study

BACKGROUND

Alopecia areata (AA), a prevalent form of autoimmune hair loss, has a not well-defined relationship with atopic and allergic disorders, including eczema, hay fever, and asthma.

OBJECTIVES

This study aims to elucidate the genetic relationship between atopy, allergies, and alopecia areata (AA) using Mendelian randomization. We hypothesize that atopic and allergic conditions contribute to the genetic predisposition of AA.

METHODS

We analyzed extensive genetic data from Genome-wide Association Studies (GWAS) involving over one million individuals. This analysis focused on assessing the genetic correlation between AA and various allergic conditions, including hay fever, eczema, asthma, and allergies to pollen, dust, and cats. The inverse variance weighted method served as our primary analytical tool, complemented by sensitivity analyses to verify the robustness of our results.

RESULTS

Our findings reveal a significant genetic correlation between atopy/allergies and an increased risk of AA. Notably, strong associations were observed for hay fever, eczema, asthma, and specific allergies (pollen, dust, and cats). The sensitivity analyses corroborated these associations, reinforcing the reliability of our primary results.

CONCLUSIONS

This study provides compelling genetic evidence of an association between atopic and allergic conditions and the development of AA. These findings suggest that individuals with such conditions may benefit from enhanced surveillance for early signs of AA.

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.

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.

Target Occupancy and Functional Inhibition of JAK3 and TEC Family Kinases by Ritlecitinib in Healthy Adults: An Open-Label, Phase 1 Study

Ritlecitinib is a small molecule in clinical development that covalently and irreversibly inhibits Janus kinase 3 (JAK3) and the TEC family of kinases (BTK, BMX, ITK, TXK, and TEC). This phase 1, open-label, parallel-group study assessed target occupancy and functional effects of ritlecitinib on JAK3 and TEC family kinases in healthy participants aged 18-60 years who received 50 or 200 mg single doses of ritlecitinib on day 1. Blood samples to assess ritlecitinib pharmacokinetics, target occupancy, and pharmacodynamics were collected over 48 hours. Target occupancy was assessed using mass spectroscopy. Functional inhibition of JAK3-dependent signaling was measured by the inhibition of the phosphorylation of its downstream target signal transducer and activator of transcription 5 (pSTAT5), following activation by interleukin 15 (IL-15). The functional inhibition of Bruton's tyrosine kinase (BTK)-dependent signaling was measured by the reduction in the upregulation of cluster of differentiation 69 (CD69), an early marker of B-cell activation, following treatment with anti-immunoglobulin D. Eight participants received one 50 mg ritlecitinib dose and 8 participants received one 200 mg dose. Ritlecitinib plasma exposure increased in an approximately dose-proportional manner from 50 to 200 mg. The maximal median JAK3 target occupancy was 72% for 50 mg and 64% for 200 mg. Ritlecitinib 50 mg had >94% maximal target occupancy of all TEC kinases, except BMX (87%), and 200 mg had >97% for all TEC kinases. For BTK and TEC, ritlecitinib maintained high target occupancy throughout a period of 48 hours. Ritlecitinib reduced pSTAT5 levels following IL-15- and BTK-dependent signaling in a dose-dependent manner. These target occupancy and functional assays demonstrate the dual inhibition of the JAK3- and BTK-dependent pathways by ritlecitinib. Further studies are needed to understand the contribution to clinical effects of inhibiting these pathways.

A Review of Dupilumab-Induced Adverse Events to Dermatologists and the Potential Pathogenesis in the Treatment of Atopic Dermatitis

Dupilumab, a monoclonal antibody targeting interleukin-4 antibody, is approved for use in many type 2 inflammatory diseases, including atopic dermatitis. It is generally well tolerated with no need of routine laboratory monitoring. However, several adverse events have been reported during real-world practice and in pivotal trials. We conducted a systematic literature research of the PubMed, Medline, and Embase databases to identify articles recording the clinical manifestation and potential pathogenesis of these adverse events with interests (AEIs) to dermatologists. In total, 547 cases from 134 studies have developed 39 AEIs 1 day to 2.5 years after dupilumab treatment. The most common AEIs are facial and neck dermatitis (299 cases), psoriasis (70 cases), arthralgia (56 cases), alopecia (21 cases), cutaneous T cell lymphoma (19 cases), severe ocular diseases (19 cases), and drug eruption (6 cases). Most of the AEIs recorded in this review resolved or improved after dupilumab discontinuation or the addition of another treatment, whereas 3 of the cases died of severe AEI. The potential pathogenesis included T help type 1 (Th1)/T help type 2 (Th2) imbalance, Th2/T help type 17 (Th17) imbalance, immune reconstitution, hypersensitivity reaction, transient hypereosinophilia related, and Th1 suppression. Clinicians should be alert of these AEIs for timely diagnosis and appropriate treatment.

Protein kinases: drug targets for immunological disorders

Protein kinases play a major role in cellular activation processes, including signal transduction by diverse immunoreceptors. Given their roles in cell growth and death and in the production of inflammatory mediators, targeting kinases has proven to be an effective treatment strategy, initially as anticancer therapies, but shortly thereafter in immune-mediated diseases. Herein, we provide an overview of the status of small molecule inhibitors specifically generated to target protein kinases relevant to immune cell function, with an emphasis on those approved for the treatment of immune-mediated diseases. The development of inhibitors of Janus kinases that target cytokine receptor signalling has been a particularly active area, with Janus kinase inhibitors being approved for the treatment of multiple autoimmune and allergic diseases as well as COVID-19. In addition, TEC family kinase inhibitors (including Bruton's tyrosine kinase inhibitors) targeting antigen receptor signalling have been approved for haematological malignancies and graft versus host disease. This experience provides multiple important lessons regarding the importance (or not) of selectivity and the limits to which genetic information informs efficacy and safety. Many new agents are being generated, along with new approaches for targeting kinases.

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.

Alopecia Areata: Current Treatments and New Directions

Alopecia areata is an autoimmune hair loss disease that is non-scarring and is characterized by chronic inflammation at the hair follicle level. Clinically, patients' presentation varies from patchy, circumscribed scalp involvement to total body and scalp hair loss. Current management is guided by the degree of scalp and body involvement, with topical and intralesional steroid injections as primarily first-line for mild cases and broad immunosuppressants as the mainstay for more severe cases. Until recently, the limited number of blinded, randomized, placebo-controlled clinical trials for this disease had made establishing an evidence-based treatment paradigm challenging. However, growing insights into the pathogenesis of alopecia areata through blood and tissue analysis of human lesions have identified several promising targets for therapy. T-helper (Th) 1/interferon skewing has traditionally been described as the driver of disease; however, recent investigations suggest activation of additional immune mediators, including the Th2 pathway, interleukin (IL)-9, IL-23, and IL-32, as contributors to alopecia areata pathogenesis. The landscape of alopecia areata treatment has the potential to be transformed, as several novel targeted drugs are currently undergoing clinical trials. Given the recent US FDA approval of baricitinib and ritlecitinib, Janus kinase (JAK) inhibitors are a promising drug class for treating severe alopecia areata cases. This article will review the efficacy, safety, and tolerability of current treatments for alopecia areata, and will provide an overview of the emerging therapies that are leading the revolution in the management of this challenging disease.

Comorbid Conditions Associated with Alopecia Areata: A Systematic Review and Meta-analysis

BACKGROUND

Alopecia areata (AA) is a complex autoimmune condition resulting in nonscarring hair loss. In recent years, many studies have provided new evidence on comorbid diseases present in patients with AA. However, some studies have conflicting results, and analyses conducting a comprehensive approach are lacking.

OBJECTIVE

The aim of our study was to provide an updated systematic review and meta-analysis of medical comorbidities associated with AA.

METHODS

We searched PubMed, Embase, and Web of Science for case-control, cross-sectional, and cohort studies investigating medical comorbidities in AA published from inception through 1 February 2023.

RESULTS

We screened 3428 abstracts and titles and reviewed 345 full text articles for eligibility. Ultimately, 102 studies were analyzed, comprising 680,823 patients with AA and 72,011,041 healthy controls. Almost all included studies (100 of 102 studies) were of satisfactory to high quality (Newcastle-Ottawa scale score ≥ 4). Among patients with AA, comorbidities with the highest odds ratios (OR) compared with healthy controls and data available from more than one study included vitamin D deficiency (OR 10.13, 95% CI 4.24-24.20), systemic lupus erythematous (OR 5.53, 95% CI 3.31-9.23), vitiligo (OR 5.30, 95% CI 1.86-15.10), metabolic syndrome (OR 5.03, 95% CI 4.18-6.06), and Hashimoto's thyroiditis (OR 4.31, 95% CI 2.51-7.40). AA may be a protective factor for certain disorders, for which the AA group had lower odds compared with healthy controls, such as irritable bowel syndrome (OR 0.38, 95% CI 0.14-0.99) and colorectal cancer (OR 0.61, 95% CI 0.42-0.89).

CONCLUSION

These findings corroborate and contextualize the risks across comorbidities for patients with AA. Further work should be done to identify the underlying pathophysiology and understand appropriate screening criteria.

Efficacy, safety, and Pharmacoeconomics of Three Common Strategies for Pediatric Alopecia Areata Patients: A Retrospective Cohort Study

Objective

To evaluate and explore the efficacy, safety, and pharmacoeconomics of three common strategies for pediatric alopecia areata.

Methods

Chinese pediatric alopecia areata patients meeting the criteria were included and divided into three groups based on the received treatments. The efficacy, adverse events and pharmacoeconomics of these treatments were retrospectively analyzed.

Results

Twenty-four pediatric AA patients were recruited in this study. 100% (12/12) of patients from the traditional group achieved SALT100. In the tofacitinib group, 40.0% (2/5) of patients achieved SALT50. 20.0% (1/5) of patients achieved SALT75 and 40.0% (2/5) of patients achieved SALT100. In the MN group, 42.86% (3/7) of patients were non-responders. 14.28 (1/7) of patients achieved SALT75 and 42.86% (3/7) of patients achieved SALT100. The adverse effects (AEs) were mild in all three groups, and none of the patients discontinued the treatments due to the AEs. Comparing the other two groups, the MN treatment would be more time-intensive and more expensive.

Conclusion

For newly diagnosed or naive pediatric patients, the traditional treatment was the first-line approach. For long-duration, severe and refractory patients, tofacitinib and microneedling can be alternative options.

Case report: Dupilumab therapy for alopecia areata in a 4-year-old patient resistant to baricitinib

Alopecia areata (AA) is a non-scarring hair loss disorder. Alopecia totalis (AT) and alopecia universalis (AU) are the severe subtypes of AA. Age of onset before 6 years of age, disease duration of more than 1 year, and extensive alopecia involving more than 50% of the scalp (including AT or AU) suggest a poorer prognosis. Topical corticosteroids are the preferred first-line treatment for pediatric AA. While some treatments, such as intralesional corticosteroids, systemic steroids, contact immunotherapy with squaric acid dibutyl ester, and JAK inhibitors, showed efficacy in adults with AA, their safety profiles limit their use in pediatric AA patients. Dupilumab is a biologic that effectively addresses the patho-physiology of Th2 allergic diseases, and treats atopic diseases by inhibiting the helper Th2 immune axis. AA has been reported to be significantly improved with dupilumab for atopic dermatitis (AD) in children and adults. We report hair regrowth over all of the scalp, eyebrows, and eyelashes after 10 months of dupilumab therapy in a 4-year-old AU patient resistant to baricitinib.

The relative efficacy of monotherapy with Janus kinase inhibitors, dupilumab and apremilast in adults with alopecia areata: Network meta-analyses of clinical trials

BACKGROUND

Janus kinase (JAK) inhibitors, biologics, and phosphodiesterase-4 (PDE-4) inhibitors are recent therapies for alopecia areata (AA)-albeit, knowledge gaps exist for these agents' relative efficacy.

OBJECTIVES

We determined the relative efficacy and safety of monotherapy with the aforementioned agents in adults with AA.

METHODS

The literature was systematically searched; we used data from randomized trials that investigated the agents' efficacy-as per Severity of Alopecia Tool (SALT) scores. Bayesian network meta-analyses were used to determine relative efficacy and safety. Effect modification was determined using a generalized linear model on aggregate data; evidence quality was evaluated.

RESULTS

Based on the surface under the cumulative ranking curve estimates obtained from multiple efficacy endpoints, regimens with the highest likelihood of achieving percent reduction in SALT scores, as well as a minimum 90%, 75% or 50% reduction in SALT scores are (in alphabetical order) baricitinib 4 mg once daily (QD), brepocitinib 60/30 mg QD, deuruxolitinib (CTP-543) 12 mg twice daily (BID), ritlecitinib 200/50 mg QD, ruxolitinib 20 mg BID and tofacitinib 5 mg BID. In contrast, dupilumab subcutaneous injections administered weekly and apremilast 30 mg BID were less likely to be effective. Discontinuation due to any adverse event was the least likely with oral JAK inhibitors, and more likely with dupilumab and apremilast.

CONCLUSIONS

Our results support the conduct of high-quality comparative trials to determine whether JAK inhibitors are more effective and safer than PDE4 inhibitors.

Hair repigmentation and regrowth in a dupilumab-treated paediatric patient with alopecia areata and atopic dermatitis: a case report

Alopecia areata (AA) is a chronic inflammatory disease mainly involving Th1 immunoreaction, but Th2 is also involved. A 9-year-old girl presented to our clinic with severe alopecia for 2 months and pruritus-related rashes for 8 years. She was diagnosed with AA and atopic dermatitis (AD), and the Severity of Alopecia Tool (SALT) score was 98. She used a 0.05% halometasone cream (occlusive dressing) topically applied overnight (6 days weekly) for 10 months. After 2 months of treatment, she had regrowth of both black and white hair. However, relapse occurred and she gradually lost all black terminal hair, but white terminal hair remained, with a SALT score of 70. Continuous topical occlusion resulted in white hair regrowth with a SALT score of 20 at the end of month 10. Dupilumab was initially prescribed as a 600-mg subcutaneous injection and maintained at 300 mg every 4 weeks thereafter. Hair repigmentation (10% of whole hair density) started, with black hair shaft appearing at the proximal end in parietal-occipital and occipital areas after three injections at week 12 of dupilumab therapy, with a SALT score of 10. After seven injections at week 28, the percentage of black hair shaft reached up to 90, and she regained her black hair and the pigmented section of hair shaft continued to grow longer at the rate of normal hair growth. Nevertheless, 4 months after termination of dupilumab therapy, the black terminal hair began to fall off, and white vellus hair gradually regrew on the scalp, with a SALT score of 80. Dupilumab induces hair regrowth and repigmentation of white terminal hair without disturbing the anagen phase of hair follicles. Therefore, melanocytes in AA may be a potential target of Th2-related factors. Persistent regrowth of white hair may be used as a signal of Th2 dominance in AA management.

Medication-induced hair loss: An update

This article discusses drug-induced hair loss, which can occur with many drugs including cytotoxic agents, biologics, and immunomodulating agents, among others. It outlines the diagnosis and management of drug-induced alopecia, with a focus on recently implicated drugs.

Overview of alopecia areata for managed care and payer stakeholders in the United States

Alopecia areata (AA) is an autoimmune disease with a complex pathophysiology resulting in nonscarring hair loss in genetically susceptible individuals. We aim to provide health care decision makers an overview of the pathophysiology of AA, its causes and diagnosis, disease burden, costs, comorbidities, and information on current and emerging treatment options to help inform payer benefit design and prior authorization decisions. Literature searches for AA were conducted using PubMed between 2016 and 2022 inclusive, using search terms covering the causes and diagnosis of AA, pathophysiology, comorbidities, disease management, costs, and impact on quality of life (QoL). AA is a polygenic autoimmune disease that significantly impacts QoL. Patients with AA face economic burden and an increased prevalence of psychiatric disease, as well as numerous systemic comorbidities. AA is predominantly treated using corticosteroids, systemic immunosuppressants, and topical immunotherapy. Currently, there are limited data to reliably inform effective treatment decisions, particularly for patients with extensive disease. However, several novel therapies that specifically target the immunopathology of AA have emerged, including Janus kinase (JAK) 1/2 inhibitors such as baricitinib and deuruxolitinib, and the JAK3/tyrosine kinase expressed in hepatocellular carcinoma (TEC) family kinase inhibitor ritlecitinib. To support disease management, a disease severity classification tool, the Alopecia Areata Severity Scale, was recently developed that evaluates patients with AA holistically (extent of hair loss and other factors). AA is an autoimmune disease often associated with comorbidities and poor QoL, which poses a significant economic burden for payers and patients. Better treatments are needed for patients, and JAK inhibitors, among other approaches, may address this tremendous unmet medical need. DISCLOSURES: Dr King reports seats on advisory boards for and/or is a consultant and/or clinical trial investigator for AbbVie, Aclaris Therapeutics Inc, AltruBio Inc, Almirall, Arena Pharmaceuticals, Bioniz Therapeutics, Bristol Meyers Squibb, Concert Pharmaceuticals Inc, Dermavant Sciences Inc, Eli Lilly and Company, Equillium, Incyte Corp, Janssen Pharmaceuticals, LEO Pharma, Otsuka/Visterra Inc, Pfizer, Regeneron, Sanofi Genzyme, TWi Biotechnology Inc, and Viela Bio; and speakers bureaus for AbbVie, Incyte, LEO Pharma, Pfizer, Regeneron, and Sanofi Genzyme. Pezalla is a paid consultant to Pfizer for market access and payer strategy concerns; Fung, Tran, Bourret, Takiya, Peeples-Lamirande, and Napatalung are employees of Pfizer and hold stock in Pfizer. This article was funded by Pfizer.

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.

Allergen desensitization reduces the severity of relapsed alopecia areata in dust-mite allergic patients

Atopy may be a facilitating factor in some alopecia areata (AA) patients with early disease onset and more severe/extensive AA. The underlying immune mechanisms are unknown, but allergen responses may support a pro-inflammatory environment that indirectly promotes AA. To investigate the long-term effect of allergen immunotherapy (AIT) against house dust mite (HDM) allergy on disease severity and prognosis for AA patients. An observational comparative effectiveness study was conducted on 69 AA patients with HDM allergy. 34 patients received conventional/traditional AA treatment (TrAA) plus AIT (AIT-TrAA), and 35 patients received TrAA alone. Serum total immunoglobulin E (tIgE), HDM specific IgE (sIgE), HDM specific IgG4 (sIgG4) and cytokines (IL-4, IL-5, IL-10, IL-12, IL-13, IL-33, IFNγ) were quantified in these patients, together with 58 non-allergic AA patients and 40 healthy controls. At the end of the 3-year desensitization course, the AIT-TrAA group presented with lower SALT scores than the TrAA group, especially in non-alopecia totalis/universalis (AT/U) patients and pre-adolescent AT/U patients (age ≤ 14). In patients with elevated tIgE levels before AIT, a decrease in tIgE was correlated to reduced extent of AA on completion of the AIT course. After desensitization, elevation of IL-5 and decrease of IL-33 were observed in HDM allergic-AA patients. Desensitization to HDM in allergic AA patients reduces the severity of relapse-related hair loss over the 3-year AIT treatment course, possibly via opposing Th2 dominance. This adjunctive treatment may help reduce disease severity and curtail the disease process in allergic patients with AA.

Systematic review of newer agents for the management of alopecia areata in adults: Janus kinase inhibitors, biologics and phosphodiesterase-4 inhibitors

Management options for moderate-to-severe alopecia areata (AA) are limited owing to a lack of safe and effective treatments suitable for long-term use. However, newer agents have the potential to induce and maintain hair regrowth in patients with a better side-effects profile compared to systemic steroids or conventional systemic agents. In this article, we conducted a systematic review of newer agents, including Janus kinase (JAK) inhibitors, biologics and phosphodiesterase-4 (PDE-4) inhibitors, for the treatment of AA in adult patients evaluated in randomized controlled trials (RCTs) using the Severity of Alopecia Tool score. A literature search was performed on PubMed and ClinicalTrials.gov, which identified 106 items with 12 RCTs eligible for review. Information regarding the treatment regimen, duration, endpoints, efficacy and adverse events were extracted; product monograph information was also summarized for approved agents with or without indications for AA. Overall, current data suggest the oral JAK inhibitors (baricitinib, ritlecitinib, deuruxolitinib, brepocitinib) as a promising new class of agents that can induce significant hair regrowth, with mild to moderate adverse effects. Baricitinib recently received US FDA approval for the treatment of severe AA, while ritlecitinib and deuruxolitinib have received the breakthrough therapy designation for AA. In contrast, PDE-4 inhibitors (apremilast) and the biologics (dupilumab, secukinumab and aldesleukin) appear to have limited efficacy thus far. Results from ongoing and future long-term studies could shed light on the utility of the newer agents in altering the progression of AA.

Recent advances in the genetics of alopecia areata

Alopecia areata (AA) is a common autoimmune-mediated hair loss disorder in humans with an estimated lifetime risk of approximately 2 %. Episodes of hair loss usually begin with isolated hairless patches that may progress to complete hair loss over the entire body. A familial occurrence of AA is well established, with recurrence risks of about 6-8 % in first-degree relatives. AA is a multifactorial disorder involving both environmental and genetic risk factors. Previous research has identified 14 susceptibility loci, most of which implicate genes involved in the immune response. The following review presents a summary of the latest findings from genome-wide association, sequencing and gene expression studies of AA, as well as their contribution to the recent therapeutic developments.

Dupilumab in Inflammatory Skin Diseases: A Systematic Review

Dupilumab was first approved for the treatment of atopic dermatitis (AD) and blocks the signaling of interleukin (IL)-4 and -13. Several other chronic skin conditions share mechanistic overlaps with AD in their pathophysiology, i.e., are linked to type 2 inflammation. Most recently, dupilumab was approved by the U.S. Food and Drug Administration for prurigo nodularis (PN). Given its relatively good safety profile, effective off-label use of dupilumab has been reported for a multitude of dermatologic diseases and several clinical trials for dermatologic skin conditions are currently ongoing. We conducted a systematic review of applications of dupilumab in dermatology other than AD and PN by searching the databases PubMed/Medline, Scopus, Web of Science and Cochrane Library as well as the clinical trial registry ClinicalTrials.gov. We found several reports for effective treatment of bullous autoimmune diseases, eczema, prurigo, alopecia areata, chronic spontaneous urticaria, Netherton syndrome and a variety of other chronic inflammatory skin diseases.

Alopecia areata and risk of atopic and autoimmune conditions: population-based cohort study

BACKGROUND

Alopecia areata (AA) has features of both autoimmune and atopic pathogenesis, but information on the risk of people with AA developing autoimmune and atopic conditions is limited.

OBJECTIVE

To assess the prevalence and incidence of atopic and autoimmune conditions in people with AA.

METHODS

This was a population-based cohort study of 8051 adults with newly diagnosed AA (AA group) and 32 204 adults in the matched control group, using the UK Oxford-Royal College of General Practitioners (RCGP) Research and Surveillance Centre (RSC) network primary care database, 2009-2018 (trial registration number: NCT04239521). Baseline prevalence of common atopic and autoimmune conditions, and risk of new-onset atopic and autoimmune disease, were estimated.

RESULTS

Atopic and autoimmune conditions were more prevalent in the AA group than the control group (atopic 37.2% vs. 26.7%, autoimmune 11.5% vs. 7.9%). The AA group were 43% more likely to develop any new-onset atopic condition [adjusted hazard ratio (aHR) 1.43. 95% confidence interval (CI) 1.28-1.61] and 45% more likely to develop any autoimmune condition (aHR 1.45, 95% CI 1.28-1.66) compared with the control group. When examining individual conditions, the AA group were at increased risk of atopic dermatitis (aHR 1.91, 95% CI 1.67-2.19), allergic rhinitis (aHR 1.32, 95% CI 1.14-1.54), autoimmune hypothyroidism (aHR 1.65, 95% CI 1.35-2.02), systemic lupus erythematosus (aHR 4.51, 95% CI 1.88-10.82) and vitiligo (aHR 2.39, 95% CI 1.49-3.82). There was no evidence for a higher incidence of other conditions examined.

CONCLUSION

People with AA have an increased burden of atopic and autoimmune comorbidity. This supports previous work suggesting that both T helper cell (Th)1 and Th2 immune responses may be implicated in the pathogenesis of AA.

Dupilumab-associated cutaneous adverse events among adult patients with atopic dermatitis: A retrospective study

Dupilumab, a monoclonal antibody inhibiting interleukin (IL) 4 and IL-13, is approved for the treatment of moderate to severe atopic dermatitis (AD) in children aged ≥6 years, adolescents, and adults. Both clinical trials and real-life data demonstrate its efficacy and safety. However, some cutaneous adverse events (cAEs) have been observed during real-world experiences. The authors' aim was to analyze the spectrum of cAEs in patients receiving dupilumab for the treatment of AD in a real-world setting. A retrospective review of electronic medical records was conducted for 916 patients (475 males and 541 females; mean age, 50.23 ± 19.66 years [range, 18-91 years]) who had received dupilumab for a minimum of 1 month for the treatment of AD from December 2018 to November 2022 at the Department of Dermatology of University Federico II of Naples (Italy). The mean duration of dupilumab treatment was 27.31 ± 21.26 months. A total of 148 of 916 (16.15%) (90 males; mean age, 50.91 ± 15.34 years) patients reported other cAEs apart of AD flare; namely, facial redness (82 of 916; 8.95%), psoriasis (39 of 916; 4.25%), alopecia areata (11 of 916; 1.2%), skin peeling (11 of 916; 1.2%), parapsoriasis (three of 916; 0.32%), and vitiligo (two of 916; 0.21%). Thirty-one of 916 (3.38%) patients discontinued dupilumab because of cAEs (18 of 916; 1.96%) for facial redness, 10 of 916 (1.09%) for psoriasis, and three of 916 (0.32%) for parapsoriasis. In our population, most of the cAEs were mild and did not require discontinuation of dupilumab. These findings would enable dermatologists understand the cutaneous side effects of dupilumab better, resulting in improved treatment plan decisions in clinical practice.

Recent insights into comorbidities in atopic dermatitis

INTRODUCTION

The relationship between atopic dermatitis and atopic diseases such as food allergies, asthma, and allergic rhinitis in terms of co-occurrence, underlying mechanisms, and therapy is well documented. There is increasing evidence that atopic dermatitis is associated with non-atopic comorbidities such as cardiac, autoimmune, and neuropsychological comorbidities, as well as cutaneous and extracutaneous infections, establishing atopic dermatitis as a systemic disease.

AREAS COVERED

The authors reviewed evidence on atopic and non-atopic comorbidities of atopic dermatitis. A literature search was conducted in PubMed for peer-reviewed articles published until October 2022.

EXPERT OPINION

Atopic and non-atopic diseases coexist with atopic dermatitis more often than would be expected by chance. The effect of biologics and small molecules on atopic and non-atopic comorbidities may contribute to a better understanding of the relationship between atopic dermatitis and its comorbidities. Their relationship needs to be explored further to dismantle the underlying mechanism and move toward an atopic dermatitis endotype-based therapeutic approach.

Association of atopic dermatitis with autoimmune diseases: A bidirectional and multivariable two-sample mendelian randomization study

Background

Observational studies have suggested the association between atopic dermatitis (AD) and the risks of autoimmune diseases. It is still unclear, however, whether or in which direction causal relationships exist, because these associations could be confounded.

Objectives

Our study seeks to assess the possibility of AD as a cause of autoimmune diseases, and to estimate the magnitude of the causal effect.

Methods

Two-sample mendelian randomization (MR) analyses were performed using genome-wide association study (GWAS) summary-level statistics. Specifically, bidirectional MR analyses were conducted to examine the direction of association of AD with autoimmune diseases; multivariable MR analyses (MVMR1) were used to test the independence of causal association of AD with autoimmune diseases after controlling other atopic disorders (asthma and allergic rhinitis), while MVMR2 analyses were conducted to account for potential confounding factors such as smoking, drinking, and obesity. Genetic instruments for AD (Ncases=22 474) were from the latest GWAS meta-analysis. The GWAS summary data for asthma and allergic rhinitis were obtained from UK Biobank. The GWAS summary data for smoking, alcohol consumption, obesity and autoimmune diseases (alopecia areata, vitiligo, systemic lupus erythematosus, ankylosing spondylitis, rheumatoid arthritis, and type 1 diabetes) were selected from the largest GWASs available. Causal estimates were derived by the inverse-variance weighted method and verified through a series of sensitivity analyses.

Results

Genetically predicted AD linked to higher risks of rheumatoid arthritis (OR, 1.28; P=0.0068) (OR_MVMR1, 1.65; P=0.0020) (OR_MVMR2, 1.36; P<0.001), type 1 diabetes (OR, 1.37; P=0.0084) (OR_MVMR1, 1.42; P=0.0155) (OR_MVMR2, 1.45; P=0.002), and alopecia areata (OR, 1.98; P=0.0059) (OR_MVMR1, 2.55; P<0.001) (OR_MVMR2, 1.99; P=0.003) in both univariable and multivariable MR. These causal relationships were supported by sensitivity analyses. No causal effect of AD was identified in relation to systemic lupus erythematosus, vitiligo, and ankylosing spondylitis. Concerning the reverse directions, no significant association was noted.

Conclusion

The results of this MR study provide evidence to support the idea that AD causes a greater risk of rheumatoid arthritis, type 1 diabetes and alopecia areata. Further replication in larger samples is needed to validate our findings, and experimental studies are needed to explore the underlying mechanisms of these causal effects.

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.

Efficacy and safety of different JAK inhibitors in the treatment of alopecia areata: a network meta-analysis

Background

Alopecia areata (AA) is an immune disease characterized by non-scarring hair loss. With the widespread application of JAK inhibitors in immune-related diseases, attention is being given to their role in the treatment of AA. However, it is unclear which JAK inhibitors have a satisfactory or positive effect on AA. This network meta-analysis aimed to compare the efficacy and safety of different JAK inhibitors in the treatment of AA.

Methods

The network meta-analysis was performed according to the PRISMA guidelines. We included randomized controlled trials as well as a small number of cohort studies. The differences in efficacy and safety between the treatment and control groups were compared.

Results

Five randomized controlled trials, two retrospective studies, and two prospective studies involving 1689 patients were included in this network meta-analysis. In terms of efficacy, oral baricitinib and ruxolitinib significantly improved the response rate of patients compared to placebo [MD = 8.44, 95% CI (3.63, 19.63)] and [MD = 6.94, 95% CI, (1.72, 28.05)],respectively. Oral baricitinib treatment significantly improved the response rate compared to non-oral JAK inhibitor treatment [MD=7.56, 95% CI (1.32,43.36)]. Oral baricitinib, tofacitinib, and ruxolitinib treatments significantly improved the complete response rate compared to placebo [MD = 12.21, 95% CI (3.41, 43.79)], [MD = 10.16, 95% CI (1.02, 101.54)], and [MD = 9.79, 95% CI, (1.29, 74.27)], respectively. In terms of safety, oral baricitinib, tofacitinib, and ruxolitinib treatments significantly reduced treatment-emergent adverse event rates compared with conventional steroid treatment [MD = 0.08, 95% CI (0.02, 0.42)], [MD = 0.14, 95% CI (0.04, 0.55)], and [MD = 0.35, 95% CI, (0.14, 0.88)], respectively.

Conclusion

Oral baricitinib and ruxolitinib are excellent options for the treatment of AA owing to their good efficacy and safety profiles. In contrast, non-oral JAK inhibitors do not appear to have satisfactory efficacy in treating AA. However, further studies are required to verify the optimal dose of JAK inhibitors for AA therapy.

Alopecia Areata in Latin America: Where are We and Where are We Going?

Alopecia areata (AA) represents an underrecognized burden in Latin America (LA), severely impacting quality of life (QoL). This impact is exacerbated by limited access to specialized dermatologic care and therapies for AA within and among nations. Many of the unmet needs for AA globally also exist in LA. The region has geographic, ethnic, cultural, and economic conditions. With new AA medicines targeting immunologic pathways on the horizon, LA must prepare regarding regulatory issues, reimbursement, awareness, and education to give adequate and timely treatment for patients with AA. To address these issues, the Americas Health Foundation convened a panel of six dermatologists from Argentina, Brazil, Colombia, and Mexico who are experts in AA and its comorbidities for a 3-day virtual meeting to discuss AA diagnosis and treatment in LA and create a manuscript offering recommendations to address discussed barriers. This publication examines unmet AA needs in LA, treatment, and innovative therapies and recommends improving AA care. Access constraints to conventional and novel medicines hinder appropriate treatments for patients. Therapy initiation delays can affect QoL, mental health, and disease progression. People with AA face stigmas, discrimination, and misconceptions owing to a lack of disease awareness. With promising new treatments for AA on the horizon, all stakeholders must coordinate efforts to enhance LA's AA management landscape and improve patient outcomes.

Dupilumab for alopecia areata treatment: A double-edged sword?

Alopecia areata (AA), which is a common and inflammatory hair loss and one of the most frequent dermatological conditions with higher incidence worldwide, the complex interplay involved multiple factors was contributed to the pathogenesis that consists of immune privilege losing and destruction with autoimmune-mediated in hair follicle also the abnormal regulation of inflammatory pathways was highlighted, although it was remained unclear to date.(J Am Acad Dermatol, 78, 2018, 1) Some treatment options for AA were proposed with great advances in recent years, but the options and efficacy were limited, such as platelet-rich plasma, JAK-STAT inhibitor, PDE4 inhibitor, and others, also the good response with regrow hair of cytokine-targeted therapy like dupilumab, ustekinumab was shown.(Clin Exp Med, 21, 2021, 215; Drugs, 80, 2020, 635) Here, we present a case with onset of AA following dupilumab treatment, the chronological relationship between the AA onset and dupilumab use should be known and emphasized.

Analysis of alopecia areata surveys suggests a threshold for improved patient-reported outcomes

BACKGROUND

Although alopecia areata (AA) greatly impacts patients' quality of life (QoL), there is no adequate validation of AA-targeted QoL surveys in clinical trials, hindering sufficient representation of patient-reported outcomes.

OBJECTIVES

Better understanding of patient-reported outcomes may guide treatment goals and future clinical trials.

METHODS

In a recent randomized controlled trial testing dupilumab in AA, patients were administered the Alopecia Areata Quality of Life Index (AA-QLI) and the Alopecia Areata Symptom Impact Scale (AASIS) surveys, specifically evaluating QoL in patients with AA. An in-depth analysis was performed to assess the utility of these questionnaires in this patient population, both at baseline and after treatment, and to determine a threshold for improved patient-reported outcomes.

RESULTS

While AASIS correlated with baseline Severity of Alopecia Tool (SALT) scores and with therapeutic response, AA-QLI showed no correlation with AA severity before or after treatment. Itch strongly correlated with serum IgE levels across both surveys. Using various approaches to estimate a discriminative threshold for decreased impact of AA on QoL (by AASIS) following treatment, a SALT score of 20 points or less post-treatment was associated with improved patient-reported outcomes, including both AA-related symptoms and items within the daily activities/feelings domain such as 'feeling sad' and 'feeling anxious or worry'.

CONCLUSIONS

AASIS is better than AA-QLI to assess patient-reported outcomes. SALT ≤ 20 following treatment should be considered as a threshold for meaningful therapeutic outcome and as a clinical endpoint in future clinical trials for AA. What is already known about this topic? Alopecia areata greatly compromises quality of life, and affected patients have increased prevalences of depression, anxiety and social phobia. Despite the significant negative impact of the disease on patients' wellbeing, validation of targeted questionnaires in alopecia areata is lacking, and a therapeutic response threshold for improved patient-reported outcomes is unknown. What does this study add? This study investigated the utility of two different alopecia areata-targeted questionnaires - Alopecia Areata Quality of Life Index and Alopecia Areata Symptom Impact Scale (AASIS) - in a clinical trial setting. AASIS was found to correlate strongly with alopecia areata severity and clinical response. What are the clinical implications of this work? Patients with ≤ 20% scalp hair loss after treatment reported improvement in multiple quality-of-life items, suggesting this as a meaningful therapeutic outcome that may guide clinicians and improve the development of future clinical trials.

Short communication: Comments on hair disorders associated with dupilumab based on VigiBase

Background

Dupilumab is a human antibody that blocks the signaling of both interleukin-4 and interleukin-13 receptors. It has been approved for the treatment of moderate-to-severe atopic dermatitis. However, several case reports have reported conflicting effects of dupilumab on alopecia.

Objectives

This study aimed to examine dupilumab-related hair disorders using the large real-world database, VigiBase.

Methods

All individual case safety reports associated with dupilumab in the Uppsala Monitoring Center VigiBase until December 29, 2019, were analyzed. Hair disorder-related terms were defined in High Level Terms with “alopecias,” “pilar disorders NEC (not elsewhere classified),” and “hypertrichoses,” using the Medical Dictionary for Regulatory Activities Hierarchy. Hair disorder reports associated with dupilumab and other biologics that inhibit the Th2 axis (omalizumab, mepolizumab, reslizumab, and benralizumab) were analyzed to determine their association with hair disorders. Disproportionality analysis was performed based on the proportional reporting ratio, reporting odds ratio, and information components.

Results

Among the 20,548 total dupilumab adverse event (AE) reports, hair disorders were reported in 462 dupilumab cases (2.2%), most of which reported hair loss, and only eight cases reported an increase in hair growth. The paradoxical trend in hair loss and growth after dupilumab use was confirmed using a disproportionality analysis. Among the other investigated biologics on Th2 immunity, only omalizumab was associated with hair loss. Additionally, hair disorders after dupilumab treatment were more frequently reported in women than in men. The proportion of hair disorder cases was high in Europe, accounting for 20.8% of hair disorder reports, whereas only 9.7% of all dupilumab-related AEs were reported in Europe. In conclusion, our analysis using a large real-world database confirmed that dupilumab is associated with hair disorders.

Translational impact of omics studies in alopecia areata: recent advances and future perspectives

INTRODUCTION

Alopecia areata (AA) is a non-scarring, hair loss disorder and a common autoimmune-mediated disease with an estimated lifetime risk of about 2%. To date, the treatment of AA is mainly based on suppression or stimulation of the immune response. Genomics and transcriptomics studies generated important insights into the underlying pathophysiology, enabled discovery of molecular disease signatures, which were used in some of the recent clinical trials to monitor drug response and substantiated the consideration of new therapeutic modalities for the treatment of AA such as abatacept, dupilumab, ustekinumab and Janus Kinase (JAK) inhibitors.

AREAS COVERED

In this review, genomics and transcriptomics studies in AA are discussed in detail with particular emphasis on their past and prospective translational impacts. Microbiome studies are also briefly introduced.

EXPERT OPINION

The generation of large datasets using the new high-throughput technologies has revolutionized medical research and AA has also benefited from the wave of omics studies. However, the limitations associated with JAK inhibitors and clinical heterogeneity in AA patients underscore the necessity for continuing omics research in AA for discovery of novel therapeutic modalities and development of clinical tools for precision medicine.

Alopecia areata: Current understanding of the pathophysiology and update on therapeutic approaches, featuring the Japanese Dermatological Association guidelines

Alopecia areata (AA) is a relatively common nonscarring hairloss disease characterized by an autoimmune response to anagen hair follicles (HFs). Accumulated evidence suggests that collapse of the HF immune privilege subsequent to triggering events, represented by viral infection, leads to autoimmune response in which autoreactive cytotoxic CD8+NKG2D+ T cells mainly target exposed HF autoantigens. AA had been recognized as type 1 inflammatory disease, but recent investigations have suggested some roles of type 2- and Th17-associated mediators in AA pathogenesis. The significance of psychological stress in AA pathogenesis is less emphasized nowadays, but psychological comorbidities, such as depression and anxiety, attract greater interest in AA management. In this regard, the disease severity may not solely be evaluated by the extent of hair loss. Use of trichoscopy markedly improved the resolution of the diagnosis and evaluation of the phase of AA, which is indispensable for the optimization of treatment. For the standardization of AA management, the establishment of guidelines/expert consensus is pivotal. Indeed, the Japanese Dermatological Association (JDA) and other societies and expert groups have published guidelines/expert consensus reports, which mostly recommend intralesional/topical corticosteroid administration and contact immunotherapy as first-line treatments, depending on the age, disease severity, and activity of AA. The uniqueness of the JDA guidelines can be found in their descriptions of intravenous corticosteroid pulse therapy, antihistamines, and other miscellaneous domestically conducted treatments. Considering the relatively high incidence of spontaneous regression in mild AA and its intractability in severe subsets, the importance of course observation is also noted. Evidenced-based medicine for AA is currently limited, however, novel therapeutic approaches, represented by JAK inhibitors, are on their way for clinical application. In this review, the latest understanding of the etiopathogenesis and pathophysiology, and update on therapeutic approaches with future perspectives are summarized for AA, following the current version of the JDA AA management guidelines.