Incident alopecia areata and vitiligo in adult women with atopic dermatitis: Nurses' Health Study 2

Global, regional and national epidemiology of alopecia areata: a systematic review and modelling study

BACKGROUND

Alopecia areata (AA) is a chronic autoimmune disease that leads to a high psychiatric, economic and systemic disease burden. A comprehensive understanding of AA epidemiology is essential for evaluating healthcare source utilization; however, a systematic approach to summarizing epidemiological data on AA is lacking.

OBJECTIVES

To investigate systematically the global, regional and national incidence and prevalence of AA.

METHODS

A structured search was conducted using the databases MEDLINE, Embase, Cochrane Library, Web of Science, SciELO and Korean Journal Database from their date of inception to 4 October 2023. Studies that reported the prevalence or incidence of AA were included. We used a Bayesian hierarchical linear mixed model to analyse prevalence estimates. The primary outcomes of our study were the global, regional and national prevalence of physician-diagnosed AA for the overall population, for adults and for children. The incidence data were summarized descriptively.

RESULTS

In total, 88 studies from 28 countries were included in the analysis. The reported incidence of AA tended to be higher in adults aged 19-50 years, and this trend was consistent with its estimated prevalence. The reported prevalence in overall populations tended to be higher in men vs. women. The estimated lifetime prevalence rate of AA was 0.10% [95% credible interval (CrI) 0.03-0.39] in the general population worldwide, 0.12% (95% CrI 0.02-0.52) in adults and 0.03% (95% CrI 0.01-0.12) in children. The estimated prevalence of AA was highest in the Asian region and lowest in the African region.

CONCLUSIONS

In this study, 48% of the Global Burden of Disease regions had insufficient data on the prevalence or incidence of AA. Further studies are needed to provide epidemiological information on middle- and low-income countries. Our study may serve as a crucial reference in terms of healthcare policy decisions.

Ethnic and Racial Disparities in Clinical Manifestations of Atopic Dermatitis

Atopic dermatitis is a heterogenous inflammatory skin illness that may last for long time and affect people of different racial and ethnic backgrounds. The condition primarily appears in infants and young children. There are people living with atopic dermatitis in every country and every ethnic group, although the frequency of the disease varies greatly. Due to the varied clinical presentations that atopic dermatitis can have, it can be challenging to characterize and diagnose the disease, particularly in adults. Nevertheless, there exists a dearth of information pertaining to the various presentations of atopic dermatitis among individuals from diverse racial and cultural groups. This critical review article offers a succinct and comprehensive overview of the current findings on the epidemiology of atopic dermatitis with regards to ethnic and racial disparities. The findings hold potential significance in advancing the development of targeted treatments for personalized medicine approaches and enhancing the quality of life for patients with atopy.

Bilateral Association Between Atopic Dermatitis® and Alopecia Areata: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to explore the association between atopic Dermatitis® (AD) and alopecia areata (AA). A comprehensive search was conducted in PubMed, Embase, Cochrane, and Web of Science from the inception of each database to November 10, 2022 for relevant studies. As there is a potential bilateral association between the 2 diseases, we assessed the prevalence/incidence of AA in patients with AD and the prevalence/incidence of AD in patients with AA. A total of 29 studies involving 11,233,448 participants were included in this analysis. AA was the exposure factor in 23 studies, AD in 7 studies, and both in 1 study. The meta-analysis revealed that the prevalence of AD was 11.2% (7.7%-15.1%) in patients with AA, and the prevalence of AA was 3.2% (95% confidence interval [CI]: 0.0%-11.5%) in patients with AD. The incidence of AD in AA patients was found to vary with age (P = 0.07). Based on 7 studies, there was a significant association between AD and AA when AA was the exposure factor [odds ratio, OR, = 4.537 (95% CI: 2.409-8.544)]; based on 10 studies, there was also a significant association between AD and AA when AD was the exposure factor [OR = 2.643 (95% CI: 1.737-3.995)]. In conclusion, this meta-analysis demonstrated the 2-way association between AD and AA, providing a clinical reference for disease prevention and control.

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.

Baseline Levels of Circulating Inflammatory Biomarkers Stratify Patients with Vitiligo Who Significantly Repigment after Treatment with Ruxolitinib Cream

BACKGROUND

Efficacy of ruxolitinib cream, a topical Jak1/Jak2 inhibitor, was demonstrated in a phase 2 trial in patients with vitiligo.

OBJECTIVE

This study aimed to characterize circulating inflammatory biomarker profiles in patients who demonstrated ≥50% improvement in facial Vitiligo Area Scoring Index scores by week 24 (group 1) and those who did not (group 2).

DESIGN

This was a posthoc analysis of a multicenter, randomized, double-blind, vehicle-controlled, phase 2 study in which screening was conducted between June 7, 2017 and March 21, 2018.

POPULATION

Patients aged between 18 and 75 years with vitiligo, including depigmentation affecting ≥0.5% of body surface area on the face and ≥3% of body surface area on nonfacial areas, were eligible.

INTERVENTION

Patients applied 1.5% ruxolitinib cream to lesions once or twice daily for 52 weeks.

MAIN OUTCOMES AND MEASURES

Patients were grouped by achievement of ≥50% improvement in facial Vitiligo Area Scoring Index at week 24. Proteomic analysis was performed on baseline serum samples.

RESULTS

Mean ± standard error facial Vitiligo Area Scoring Index in group 1 (n = 30) versus group 2 (n = 27) improved by 79.9 ± 4.0% versus 1.1 ± 7.3% and 91.9 ± 1.5% versus 25.1 ± 13.4% at weeks 24 and 52, respectively. Broad proteomic analysis revealed 76 proteins (of 1,104 tested) that were differentially expressed between groups 1 and 2 at baseline (P < 0.05). Ten distinct proteins were upregulated in group 1; 64 were elevated in group 2.

CONCLUSION

This analysis identified potential differences between patients who achieved ≥50% improvement in facial Vitiligo Area Scoring Index at 24 weeks and those who did not that require deeper scientific interrogation and may be important in stratifying therapeutic benefit for patients with vitiligo.

TRIAL REGISTRATION

The original study was registered at ClinicalTrials.gov, NCT03099304.

Disease modification in inflammatory skin disorders: opportunities and challenges

Progress in understanding of the mechanisms underlying chronic inflammatory skin disorders, such as atopic dermatitis and psoriasis vulgaris, has led to new treatment options with the primary goal of alleviating symptoms. In addition, this knowledge has the potential to inform on new strategies aimed at inducing deep and therapy-free remission, that is, disease modification, potentially impacting on associated comorbidities. However, to reach this goal, key areas require further exploration, including the definitions of disease modification and disease activity index, further understanding of disease mechanisms and systemic spillover effects, potential windows of opportunity, biomarkers for patient stratification and successful intervention, as well as appropriate study design. This Perspective article assesses the opportunities and challenges in the discovery and development of disease-modifying therapies for chronic inflammatory skin disorders.

Phenotypic and Endotypic Determinants of Atopic Dermatitis Severity From the Atopic Dermatitis Research Network (ADRN) Registry

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a highly variable clinical phenotype.

OBJECTIVE

This study aimed to identify historical and clinical features and biomarkers associated with AD severity.

METHODS

A US registry of extensively phenotyped AD participants (aged 0.73-80 years) were enrolled at 9 academic centers. Information on family and personal medical history, examination, skin swabs (culture), and serum biomarkers was collected to evaluate their association with AD severity.

RESULTS

Participants with AD (N = 2862) whose disease was categorized as mild (11.6%), moderate (58.0%), or severe (30.4%) based on Rajka-Langeland scoring were enrolled. The trend test, when adjusting for gender, race, and age, demonstrated that severity was strongly (P ≤ .04) associated with a personal/family history of allergic disorders, history of alopecia, exposure to passive smoke, ocular herpes infection, skin bacterial and viral infections, and history of arrhythmia. Features observed more frequently (P ≤ .002), as a function of severity, included skin infections (impetigo, human papillomavirus, and molluscum contagiosum virus), Staphylococcus aureus colonization, excoriations, hyperlinear palms, ichthyosis, blepharitis, conjunctivitis, ectropion, and wheezing. Serum IgE, allergen and food (≤6 years) Phadiatop, and eosinophilia were strongly linked to severity (P < .001).

CONCLUSIONS

In a diverse US AD population, severity was associated with a history of atopic disorders, skin and extracutaneous bacterial and viral infections (by history and physical examination), higher IgE, eosinophilia and allergen sensitization, atopic skin manifestations (ie, excoriation, hyperlinear palms, and ichthyosis), and atopic ocular features (ie, blepharitis, conjunctivitis, and ectropion) as well as asthma findings (ie, wheezing). Data from our prospective registry significantly advance our understanding of AD phenotypes and endotypes, which is critical to achieve optimal management.

Baricitinib for the Treatment of Alopecia Areata

Alopecia areata (AA) is a relapsing, chronic, immune-mediated disease characterized by nonscarring, inflammatory hair loss that can affect any hair-bearing site. AA clinical presentation is heterogeneous. Its pathogenesis involves immune and genetic factors and several pro-inflammatory cytokines involved in AA pathogenesis, including interleukin-15 and interferon-γ, as well as Th2 cytokines, such as IL-4/IL-13, that signal through Janus kinase (JAK) pathway. AA treatment aims to stop its progression and reverse hair loss, and JAK inhibition has been shown to stop hair loss and reverse alopecia and has exhibited promising results in treating AA in clinical trials. Baricitinib, an oral, reversible, selective JAK1/JAK2 inhibitor, was shown to be superior to placebo on hair growth after 36 weeks of treatment in adults with severe AA in a phase 2 trial and recently in two phase 3 trials (BRAVE-AA1 and BRAVE-AA2). In both studies, the most common adverse events were upper respiratory tract infections, urinary tract infection, acne, headache, and elevated creatine kinase levels. On the basis of these trial results, baricitinib was recently approved by the European Medicines Agency (EMA) and US Food and Drug Administration (FDA) for the treatment of adults with severe AA. Nevertheless, longer trials are needed to determine the long-term efficacy and safety of baricitinib in AA. Current trials are ongoing and are planned to remain randomized and blinded for up to 200 weeks.

Comorbidities of atopic dermatitis-what does the evidence say?

Atopic dermatitis (AD) is a common disease that is associated with atopic and nonatopic comorbidities. There has been a growing interest in this area of AD, because presence or risk of comorbidities can in many ways impact the management of patients with AD. Thus, some treatments for AD may improve its comorbidities as well, whereas others may increase their risk. In this review article, we discuss various comorbidities of AD mostly on the basis of the results of recent multiple systematic reviews and meta-analyses to update readers about this rapidly developing area of dermatology. We emphasize the important information provided by studies presenting both relative risk and absolute risk, and show that AD is associated with, among others, atopic comorbidities such as asthma, rhinitis, and food allergy, nonatopic comorbidities such as ocular, psychiatric, infectious, endocrine, autoimmune, and cardiovascular diseases, and certain cancers. Clinicians need to be aware of these and be cognizant about positive and negative effects of existing and new treatments for AD.

Overlapping Features of Psoriasis and Atopic dermatitis: From Genetics to Immunopathogenesis to Phenotypes

Psoriasis (PSO) and atopic dermatitis (AD) were once considered to be mutually exclusive diseases, but gradually regarded as a spectrum of disease. Shared genetic loci of both diseases were noted in some populations, including Chinese. Shared immunopathogenesis involving Th17, Th1, Th22 cells, or even IL-13 was found in certain stages or phenotypes. This review discusses the overlapping genetic susceptibility, shared cytokines, immune-mediated comorbidities, and clinical presentations. Overlapping conditions could be classified into mainly PSO lesions with AD features or vice versa, concomitant PSO and AD, or disease transformation as a result of biologics treatment.

Atopic dermatitis and risk of autoimmune diseases: a systematic review and meta-analysis

Background

Atopic dermatitis is the most common chronic inflammatory skin disease and presents a major public health burden worldwide. Recent observational studies revealed the potential association between atopic dermatitis with autoimmune disorders. However, there is no meta-analysis of the prevalence or incidence of autoimmune diseases in atopic dermatitis. Therefore, considering the potential clinical implications of these associations, we aimed to assess the risk of autoimmune diseases in patients with atopic dermatitis using this method.

Methods

PubMed, Embase, and Web of Science were searched from inception to October, 2020. Observational studies which provided estimate effects with 95% CI or raw data were included. The quality of selected studies was evaluated using the Newcastle–Ottawa Scale. Odds ratio and relative risks were pooled using a random effects model and expressed with 95% confidence intervals.

Results

Fourteen observational studies were included in this systematic review and meta-analysis. The random-effects meta-analysis of case–control and cross-sectional studies showed a significant association of atopic dermatitis with mutiple autoimmune diseases, including alopecia areata, celiac disease, Crohn’s disease, rheumatoid arthritis, systematic lupus erythematosus, ulcerative colitis and vitiligo. Furthermore, pooling of the results of cohort studies showed that patients with atopic dermatitis were more likely to develop these autoimmune diseases.

Conclusion

Our meta-analysis showed that patients with atopic dermatitis were at higher risk of multiple autoimmune diseases including alopecia areata, celiac disease, Crohn’s disease, rheumatoid arthritis, systematic lupus erythematosus, ulcerative colitis and vitiligo. It is important for early detection of the affected group so that timely management can be initiated. Dermatologists and allergists should be aware of the autoimmune diseases in patients with atopic dermatitis and develop interventions if necessary. Also, limited by the present research, we still require more large-scale studies to further establish the association between atopic dermatitis and autoimmune diseases.

Prevalence and Risk Factors Associated with the Occurrence of Autoimmune Diseases in Patients with Alopecia Areata

BACKGROUND

Increased rates of autoimmune diseases (ADs) have been reported in association with alopecia areata (AA); however, the risk factors for coexisting ADs in AA patients have been poorly investigated.

OBJECTIVE

To evaluate the prevalence and factors associated with AD comorbidities in patients with AA.

METHODS

This case-control study included patients diagnosed with AA between January 2000 and March 2020. Individuals with AA, both with and without concomitant ADs, were statistically compared. Variables significantly associated with coexisting ADs were identified using univariate and multivariate logistic regression analyses. Multinomial logistic regression analysis was performed to identify the specific risk factors for each concomitant AD.

RESULTS

Among the 615 patients with AA, comorbid ADs were found in 76 (12.4%). Autoimmune thyroid disease (AITD) exhibited the highest frequency (n = 42, 6.8%), followed by vitiligo (n = 15, 2.4%), and systemic lupus erythematosus (SLE) (n = 12, 2.0%). Logistic regression analyses revealed that female sex (odds ratio [OR] = 2.45, 95% confidence interval [CI] = 1.24-4.82; P = 0.011), nail abnormalities (OR = 2.49, 95% CI = 1.14-5.46; P = 0.023), and atopic diseases (OR = 1.98, 95% CI = 1.09-2.43; P < 0.001) were significantly associated with coexisting ADs. Regarding each concomitant AD, nail abnormalities were an associated factor for AITD (OR = 4.65, 95% CI = 1.96-7.24; P = 0.01), whereas coexisting atopic diseases were demonstrated as a predictor of vitiligo (OR = 2.48, 95% CI = 1.43-4.58; P = 0.02). Female sex (OR = 1.61, 95% CI = 1.18-4.27; P = 0.04) and family history of AD (OR = 1.85, 95% CI = 1.26-4.19; P = 0.03) were predictors of SLE.

CONCLUSION

This study suggests that female AA patients with nail abnormalities and atopic diseases have increased rates of AD comorbidities. A thorough review of systems for associated factors can help physicians screen for concomitant ADs.

Atopic Dermatitis-Beyond the Skin

Atopic dermatitis is a chronic inflammatory disease that can arise during the first months of life or at maturity and have a significant negative impact on the quality of life. The main pathogenic mechanism is the breakdown of cutaneous barrier integrity, which is associated with systemic inflammatory immunologic disorders. Atopic dermatitis involves numerous immunologic, allergic, respiratory, and ophthalmologic comorbidities that develop through similar intricate pathogenic phenomena. The atopic march represents the evolution in time of various allergic diseases, of which food allergies often cause the first manifestations of atopy, even from a very young age. Chronic inflammation translated through specific markers, next to increased immunoglobulin E (IgE) serum levels and heterogenous clinical manifestations, argue for the inclusion of atopic dermatitis in the systemic disease category.

Biologics for Treatment of Atopic Dermatitis: Current Status and Future Prospect

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by intense pruritus and recurrent eczematous lesions that significantly impair quality of life. It is a heterogeneous disease affecting both children and adults. The treatment of moderate-to-severe forms of AD is challenging, as topical corticosteroids are often insufficient to achieve disease control or inappropriate and off-label use of immunosuppressants may have significant undesirable side effects. The development of targeted biologic therapies specifically for AD is thus highly desirable. Dupilumab is the only biologic therapy that is Food and Drug Administration approved for the treatment of moderate-to-severe AD in patients 6 years and older, with consistent long-term efficacy and safety trial data. In this article, we review the mechanisms, safety, and efficacy of dupilumab from recent clinical trials, and we review the current data, mechanism of action, clinical efficacy, and limitations of new biologics currently in phase 2 and 3 clinical trials (lebrikizumab, tralokinumab, nemolizumab, tezepelumab, and ISB 830).

EAACI Biologicals Guidelines-dupilumab for children and adults with moderate-to-severe atopic dermatitis

Atopic dermatitis imposes a significant burden on patients, families and healthcare systems. Management is difficult, due to disease heterogeneity, co-morbidities, complexity in care pathways and differences between national or regional healthcare systems. Better understanding of the mechanisms has enabled a stratified approach to the management of atopic dermatitis, supporting the use of targeted treatments with biologicals. However, there are still many issues that require further clarification. These include the definition of response, strategies to enhance the responder rate, the duration of treatment and its regimen (in the clinic or home-based), its cost-effectiveness and long-term safety. The EAACI Guidelines on the use of dupilumab in atopic dermatitis follow the GRADE approach in formulating recommendations for each outcome and age group. In addition, future approaches and research priorities are discussed.

Comorbidités de la dermatite atopique

Atopic dermatitis is associated with an increased risk of asthma (10 to 30% according to age), allergic rhinitis and conjunctivitis and food allergy. Other comorbidiies are globally lest frequent than in psoriasis. There is no increased risk of solid cancer. Smoking is a major confounding factor that has to be taken into account. Obesity and metabolic syndrome are more frequent and there is a moderately increased cardiovascular risk in severe forms of atopic dermatitis. There is a clear-cut increased risk of vitiligo and alopecia areata and a lower risk of other auto-immune diseases, including type I diabetes in children. There is a higher risk of cutaneous but not extra-cutaneous bacterial and viral infections, and increased frequency of contact dermatitis and urticaria. Severe atopic dermatitis is associated with psychiatric comorbidities, like attention disorders/hyperactivity, depression and suicidal ideas. © 2019 Elsevier Masson SAS. All rights reserved.

Alopecia Areata Is Associated with Atopic Diathesis: Results from a Population-Based Study of 51,561 Patients

BACKGROUND

Evidence of T_H1/IFN-γ overactivation as a major pathogenic driver somewhat conflicts with data supporting robust allergic background in patients with alopecia areata (AA). Previous investigations of immunological dysregulations show that both T_H1- and T_H2-related markers are overexpressed in AA. Clinical correlations in large populations may shed light on the immune pathways most likely to result in the clinical phenotype of AA.

OBJECTIVE

To investigate the atopic comorbidities among patients with AA in a large population-based study.

METHODS

This is a cross-sectional retrospective study of patients with AA and a matched comparison group, analyzing the associations between AA and 4 atopic comorbidities: asthma, atopic dermatitis (AD), allergic rhinitis, and allergic conjunctivitis. χ² and t tests were used for univariate analysis, and logistic regression model was used for multivariate analysis. The study was performed using the computerized database of the Clalit Health Services, encompassing more than 4.4 million subjects.

RESULTS

The study population included 51,561 patients with AA and 51,410 matched control subjects. The prevalence of asthma (7.8% vs 6.5%; odds ratio [OR], 1.22; 95% CI, 1.17-1.28; P < .001), AD (3.9% vs 2.6%; OR, 1.55; 95% CI, 1.44-1.66; P < .001), allergic rhinitis (16.0% vs 12.8%; OR, 1.29; 95% CI, 1.25-1.34; P < .001), and allergic conjunctivitis (23.5% vs 19.6%; OR, 1.27; 95% CI, 1.23-1.30; P < .001) was significantly higher among patients with AA as compared with matched control subjects. Patients with AA also had a significantly higher probability of having more than 1 atopic comorbidity, with increasing OR as the number of concomitant atopic conditions increased.

CONCLUSIONS

Our analysis supports the previous literature and provides strong generalizability of significant atopy in patients with AA, suggesting T_H2 pathogenicity in AA, and challenging the traditional view of AA as a single-axis, T_H1-centered disease.

Allergy promotes alopecia areata in a subset of patients

In this commentary, we focus on allergy as a facilitating factor in the pathogenesis of alopecia areata (AA). From previous studies on AA, it is well known that subsets of patients can have one or more of; seasonal relapse, comorbid atopic rhinitis, asthma and dermatitis, lesion infiltrating eosinophils and plasma cells, high levels of total IgE, specific IgE for house dust mites (HDMs), and/or disrupted skin barrier function by the evaluation of filaggrin. Allergy and AA share a similar genetic background; both contributing to an immune reaction imbalance. Furthermore, adjunctive treatment with antihistamines, or desensitization for HDM, can reduce the severity of alopecia in atopic AA patients. Therefore, allergies may contribute to the onset and relapse of AA. Identification of an allergic or atopic immune component in AA patient subsets may indicate adjunctive treatment intervention measures against allergies should be taken which may improve the success of conventional AA treatment.

Epidemiology of alopecia areata, ophiasis, totalis, and universalis: A systematic review and meta-analysis

BACKGROUND

Alopecia areata (AA) is a common autoimmune alopecia with heterogeneous severity and distribution. Previous studies found conflicting results about AA epidemiology.

OBJECTIVE

To determine the prevalence, incidence, and predictors of AA, alopecia totalis, alopecia ophiasis, and alopecia universalis.

METHODS

A systematic review of all published cohort and cross-sectional studies that analyzed AA and its subtypes. MEDLINE, Embase, LILACS, Scopus, Cochrane Library, and GREAT were searched. At least 2 reviewers performed study title/abstract review and data extraction. Random-effects meta-analysis was used because of significant heterogeneity (I² = 99.97%).

RESULTS

Ninety-four studies met the inclusion criteria. The pooled prevalence (95% confidence interval, N) of AA overall was 2.11% (1.82-2.42, N = 302,157,365), with differences of population-based (0.75% [0.49-1.06%], N = 301,173,403) and clinic-based (3.47% [3.01-3.96], N = 983,962) studies. The prevalences of alopecia totalis, ophiasis, and universalis were 0.08% (0.04-0.13, N = 1,088,149), 0.02% (0.00-0.06, N = 1,075,203), and 0.03% (0.01-0.06, N = 1,085,444), respectively. AA prevalence (95% confidence interval) increased over time (<2000: 1.02% [0.85-1.22]; 2000-2009: 1.76% [1.51-2.03]; >2009: 3.22% [2.59-3.92]; P < .0001) and differed by region. AA prevalence was significantly lower in adults (1.47% [1.18-1.80]) than children (1.92% [1.31-2.65]; P < .0001).

CONCLUSIONS

AA affects 2% of the global population. AA prevalence is lower in adults than children, is increasing over time, and significantly differs by region.

Diagnosis validation and clinical characterization of atopic dermatitis in Nurses' Health Study 2

BACKGROUND

Epidemiologic studies of atopic dermatitis (AD) are often limited by case definitions that have not been validated.

OBJECTIVE

In this study, we assessed the accuracy of self-report of AD in a large cohort of US female nurses, the Nurses' Health Study 2 (NHS2). We also provide clinical characteristics of AD in the cohort.

METHODS

We sent an electronic questionnaire to NHS2 participants who previously reported ever having a diagnosis of AD. This questionnaire was designed to confirm cases of AD using previously validated algorithms with >85% specificity. We assessed the association of AD with asthma, comparing the results when different definitions of AD were applied. We also inquired about various aspects of participants' AD.

RESULTS

Responses were received from 2509 of 5126 (49%) nurses who were sent the questionnaire, with an average age of 62. Most participants (1996/2509, 80%) reiterated their previously reported clinician diagnosis of AD. Application of the two diagnostic algorithms yielded confirmation of 1538 and 1293 prevalent cases, respectively. The association of AD with asthma was stronger when more stringent AD case definitions were applied. Participants generally reported mild disease (92% with ≤10% maximal body surface area involved) and a high proportion (57%) reported adult-onset disease.

CONCLUSIONS

Self-report of AD diagnosis has good reliability, and future analyses will be strengthened by our ability to conduct sensitivity analyses with refined confirmed AD subgroups.

JAK Inhibitors for Treatment of Alopecia Areata

The advancement of genetic and preclinical studies has uncovered the mechanisms involved in the pathogenesis of alopecia areata (AA). The development of targeted therapies using small molecules blocking specific pathways for the treatment of AA is underway. By repurposing Food and Drug Administration-approved small molecule JAK inhibitors as treatments for AA, it has been demonstrated that JAK inhibitors can effectively reverse hair loss in patients with moderate to severe AA. In this review, we summarize and discuss the current preclinical and clinical studies on JAK inhibitors, as well as the prospects of using JAK inhibitors for the treatment of AA.

The convergence theory for vitiligo: A reappraisal

Vitiligo is characterized by progressive loss of skin pigmentation. The search for aetiologic factors has led to the biochemical, the neurologic and the autoimmune theory. The convergence theory was then proposed several years ago to incorporate existing theories of vitiligo development into a single overview of vitiligo aetiology. The viewpoint that vitiligo is not caused only by predisposing mutations, or only by melanocytes responding to chemical/radiation exposure, or only by hyperreactive T cells, but rather results from a combination of aetiologic factors that impact melanocyte viability, has certainly stood the test of time. New findings have since informed the description of progressive depigmentation. Understanding the relative importance of such aetiologic factors combined with a careful selection of the most targetable pathways will continue to drive the next phase in vitiligo research: the development of effective therapeutics. In that arena, it is likewise important to acknowledge that pathways affected in some patients may not be altered in others. Taken together, the convergence theory continues to provide a comprehensive viewpoint of vitiligo aetiology. The theory serves to intertwine aetiologic pathways and will help to define pathways amenable to disease intervention in individual patients.

Atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, with a lifetime prevalence of up to 20% and substantial effects on quality of life. AD is characterized by intense itch, recurrent eczematous lesions and a fluctuating course. AD has a strong heritability component and is closely related to and commonly co-occurs with other atopic diseases (such as asthma and allergic rhinitis). Several pathophysiological mechanisms contribute to AD aetiology and clinical manifestations. Impairment of epidermal barrier function, for example, owing to deficiency in the structural protein filaggrin, can promote inflammation and T cell infiltration. The immune response in AD is skewed towards T helper 2 cell-mediated pathways and can in turn favour epidermal barrier disruption. Other contributing factors to AD onset include dysbiosis of the skin microbiota (in particular overgrowth of Staphylococcus aureus), systemic immune responses (including immunoglobulin E (IgE)-mediated sensitization) and neuroinflammation, which is involved in itch. Current treatments for AD include topical moisturizers and anti-inflammatory agents (such as corticosteroids, calcineurin inhibitors and cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4) inhibitors), phototherapy and systemic immunosuppressants. Translational research has fostered the development of targeted small molecules and biologic therapies, especially for moderate-to-severe disease.

Skin diseases associated with atopic dermatitis

Atopic dermatitis is a common chronic pruritic inflammatory skin disorder, characterized by an abnormal skin barrier, immune dysfunction, and an altered skin microbiome. Atopic dermatitis may be seen in conjunction with a variety of other skin disorders due to the complex pathogenesis of atopic dermatitis, involving genetic and environmental factors that are associated with immune dysfunction, barrier defects, and altered skin microbiomes. Skin disorders associated with atopic dermatitis include diseases sharing similar genetic origins like ichthyosis vulgaris, infectious diseases such as impetigo, and eczema herpeticum, in addition to the cutaneous autoimmune diseases, alopecia areata, and vitiligo. Atopic dermatitis is also often linked to such benign conditions as pityriasis alba and keratosis pilaris. This review discusses the cutaneous comorbidities of atopic dermatitis and their relationship via their occurrence in conjunction with atopic dermatitis.

The Changing Landscape of Alopecia Areata: The Therapeutic Paradigm

Alopecia areata (AA), a prevalent inflammatory cause of hair loss, lacks FDA-approved therapeutics for extensive cases, which are associated with very poor rates of spontaneous hair regrowth and major psychological distress. Current treatments for severe cases include broad immune-suppressants, which are associated with significant adverse effects, precluding long-term use, with rapid hair loss following treatment termination. As a result of the extent of the disease in severe cases, topical contact sensitizers and intralesional treatments are of limited use. The pathogenesis of AA is not yet fully understood, but recent investigations of the immune activation in AA skin reveal Th1/IFN-γ, as well as Th2, PDE4, IL-23, and IL-9 upregulations. Tissue analyses of both animal models and human lesions following broad-acting and cytokine-specific therapeutics (such as JAK inhibitors and ustekinumab, respectively) provide another opportunity for important insights into the pathogenesis of AA. As reviewed in this paper, numerous novel therapeutics are undergoing clinical trials for AA, emphasizing the potential transformation of the clinical practice of AA, which is currently lacking. Dermatologists are already familiar with the revolution in disease management of psoriasis, stemming from better understanding of immune dysregulations, and atopic dermatitis will soon follow a similar path. In light of these recent developments, the therapeutic arena of AA treatments is finally getting more exciting. AA will join the lengthening list of dermatologic diseases with mechanism-targeted drugs, thus changing the face of AA.