Endophenotypic Variations of Atopic Dermatitis by Age, Race, and Ethnicity

Preclinical Models of Atopic Dermatitis Suitable for Mechanistic and Therapeutic Investigations

Atopic dermatitis (AD) is a complex immune-mediated abnormality of the skin characterized by impaired barrier function, eczematous dermatitis, chronic pruritus and itch. The immunological response in AD is mediated by a Th2-dominated immune response in the early acute phase followed by a Th1/ Th2 mixed immune response in the chronic phase. AD is the first step of the "atopic march" that progresses into food allergy, allergic rhinitis, and asthma. Different models are indispensable for studying AD pathogenesis and for designing pre-clinical studies for therapeutic discovery. They reflect the characteristic morphological features of typical human AD with regard to epidermal thickening, hyperkeratosis, acanthosis, and spongiosis and help understand the immunopathogenesis of the disease with respect to IgE levels and cellular infiltration of eosinophils, mast cells, and lymphocytes. Although it is difficult to replicate all human AD clinical features in a model, several AD in vivo models comprising spontaneous, induced, transgenic, and humanized and in vitro models, including 2D, co-culture, and 3D, have been described previously. However, several questions remain regarding whether these models satisfactorily reflect the complexity of human AD. Therefore, this review comprehensively highlights the diversity of currently available models and provides insights into the selection of suitable models based on research questions. It also summarizes the diverse mechanisms associated with each model, which may be valuable for better study design to test new therapeutic options.

What is "eczema"?

Eczema is the most common category of inflammatory skin disorders as dermatologists see many patients with eczematous diseases in daily practice. It is characterized by the three major morphological features: multiple-pinpoint condition, polymorphism, and itch. To describe polymorphism, "eczema triangle" has been used in German/Japanese dermatology. The multiple pinpoints correspond to numerous tiny foci from which individual papules/vesicles arise. The polymorphism betrays composition of erythema, papule, seropapule, vesicle, pustule, scale, and crust, which are seen in acute eczema. Meanwhile, chronic eczema is represented by lichenification and hyperpigmentation, and possibly by hypopigmentation. In acute eczema, spongiosis is associated with overproduction of hyaluronic acid, secretion of self-protective galectin-7, and decreased expression of E-cadherin. In the upper dermis, Th1/Tc1 or Th2/Tc2, and additional Th17, Th22, and/or Tc22 infiltrate, depending on each eczematous disease. Innate lymphoid cells are also involved in the formation of eczema. In chronic eczema, periostin contributes to remodeling of inflammatory skin with dermal fibrosis, and epidermal melanogenesis and dermal pigment deposition result in hyperpigmentation. Finally, eczematous diseases are potentially associated with increased risk of comorbidities, including not only other allergic diseases but also coronary heart disease and mental problems such as depression. Although the original word for eczema is derived from old Greek "ekzein," eczema remains a major target of modern science and novel therapies.

Interleukin-1α inhibitor bermekimab in patients with atopic dermatitis: randomized and nonrandomized studies

Bermekimab is a human-derived recombinant monoclonal antibody that exhibits immunoregulatory activity by specifically blocking interleukin-1α activity. Four phase 2 studies evaluated efficacy and safety of bermekimab in patients with moderate-to-severe atopic dermatitis (AD). In addition, a novel human skin explant model was developed to assess bermekimab pharmacokinetics/pharmacodynamics and proteomic/transcriptomic effects. Study 1 (NCT03496974, N = 38) was an open-label, dose escalation study of subcutaneous bermekimab (200 mg or 400 mg). Study 2 (NCT04021862, N = 87) was a double-blind, placebo-controlled, randomized (1:1:1) study of subcutaneous bermekimab (400 mg every week (qw) or every 2 weeks) or placebo. GENESIS (NCT04791319, N = 198) was a double-blind, placebo- and active-comparator-controlled, randomized (1:1:2:2) study of placebo, subcutaneous bermekimab (350 mg or 700 mg qw), or dupilumab. LUNA (NCT04990440, N = 6) was a double-blind, placebo-controlled, randomized (4:1) study of intravenous bermekimab 800 mg qw or placebo. A novel human ex vivo skin pharmacodynamic assay supported phase 0 (NCT03953196) and phase 1 (NCT04544813) studies. In Study 1, 400 mg subcutaneous bermekimab showed improvement in efficacy assessments (e.g., ≥ 75% improvement of EASI over baseline, IGA 0/1, and worst itch); however, efficacy was not confirmed in Study 2 or GENESIS. Consequently, GENESIS and LUNA were terminated early. The novel human ex vivo skin pharmacodynamic assay demonstrated that bermekimab reduced downstream skin injury responses. Although bermekimab showed potential as an AD treatment in preclinical and early open-label trials, larger controlled studies (Study 2 and GENESIS) did not confirm those initial results.

Therapeutic Potential and Mechanisms of Mesenchymal Stem Cell and Mesenchymal Stem Cell-Derived Extracellular Vesicles in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic and inflammatory skin disease with intense itchiness that is highly prevalent worldwide.The pathogenesis of AD is complex and closely related to genetic factors, immunopathogenic factors, environmental factors, and skin infections. Mesenchymal stem cells (MSCs) are non-hematopoietic progenitor cells derived from the mesenchymal stroma. They have anti-inflammatory, anti-apoptotic, and regenerative properties. Numerous studies demonstrate that MSCs can play a therapeutic role in AD by regulating various immune cells, maintaining immune homeostasis, and promoting the repair of damaged tissues. The key mediators for their biological functions are extracellular vesicles (MSC-Evs) and soluble cytokines derived from MSCs. The safety and efficacy of MSCs have been demonstrated in clinical Phase I / IIa trials for AD. This paper provides a comprehensive review of the pathogenesis of AD and the currently published studies on the function of MSCs and MSC-Evs in AD, primarily including the pathogenesis and the immunomodulatory impacts of MSCs and MSC-Evs, along with advancements in clinical studies. It provides insights for comprehending AD pathogenesis and investigating treatments based on MSCs.

Eyelid dermatitis in patch-tested adult patients: a systematic review with a meta-analysis

Eyelid dermatitis (ED) affects a cosmetically significant area and leads to patients' distress. Despite ongoing and recent research efforts, ED remains a multidisciplinary problem that needs further characterization. We aimed to evaluate the atopic eyelid dermatitis (AED) frequency in ED patients and to perform their clinical profiling. PubMed databases were searched from 01.01.1980 till 01.02.2024 to PRISMA guidelines using a search strategy: (eyelid OR periorbital OR periocular) AND (dermatitis or eczema). Studies with patch-tested ED patients were included. Proportional meta-analysis was performed using JBI SUMARI software. We included 65 studies across Europe, North America, Asia and Australia, with a total of 21,793 patch-tested ED patients. AED was reported in 27.5% (95% CI 0.177, 0.384) of patch-tested ED patients. Isolated ED was noted in 51.6% (95% CI 0.408, 0.623) of 8453 ED patients with reported lesion distribution, including 430 patients with isolated AED. Our meta-analysis demonstrated that the AED frequency in patch-tested ED patients exceeded the previous estimate of 10%. Isolated AED was noted in adult patients, attending contact allergy clinics. Future studies are needed to elucidate the global prevalence and natural history of isolated AED in adults.

Celastrol alleviates atopic dermatitis by regulating Ezrin-mediated mitochondrial fission and fusion

Celastrol, a bioactive molecule extracted from the plant Tripterygium wilfordii Hook F., possesses anti-inflammatory, anti-obesity and anti-tumour properties. Despite its efficacy in improving erythema and scaling in psoriatic mice, the specific therapeutic mechanism of celastrol in atopic dermatitis (AD) remains unknown. This study aims to examine the role and mechanism of celastrol in AD using TNF-α-stimulated HaCaT cells and DNCB-induced Balb/c mice as in vitro and in vivo AD models, respectively. Celastrol was found to inhibit the increased epidermal thickness, reduce spleen and lymph node weights, attenuate inflammatory cell infiltration and mast cell degranulation and decrease thymic stromal lymphopoietin (TSLP) as well as various inflammatory factors (IL-4, IL-13, TNF-α, IL-5, IL-31, IL-33, IgE, TSLP, IL-17, IL-23, IL-1β, CCL11 and CCL17) in AD mice. Additionally, celastrol inhibited Ezrin phosphorylation at Thr567, restored mitochondrial network structure, promoted translocation of Drp1 to the cytoplasm and reduced TNF-α-induced cellular reactive oxygen species (ROS), mitochondrial ROS (mtROS) and mitochondrial membrane potential (MMP) production. Interestingly, Mdivi-1 (a mitochondrial fission inhibitor) and Ezrin-specific siRNAs lowered inflammatory factor levels and restored mitochondrial reticular formation, as well as ROS, mtROS and MMP production. Co-immunoprecipitation revealed that Ezrin interacted with Drp1. Knocking down Ezrin reduced mitochondrial fission protein Drp1 phosphorylation and Fis1 expression while increasing the expression of fusion proteins Mfn1 and Mfn2. The regulation of mitochondrial fission and fusion by Ezrin was confirmed. Overall, celastrol may alleviate AD by regulating Ezrin-mediated mitochondrial fission and fusion, which may become a novel therapeutic reagent for alleviating AD.

Efficacy and Safety of Crisaborole Ointment 2% in Chinese Patients Aged ≥ 2 Years with Mild to Moderate Atopic Dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a chronic immuno-inflammatory skin disease. Crisaborole ointment, 2%, is a nonsteroidal phosphodiesterase 4 inhibitor approved for the treatment of mild to moderate AD. This post hoc analysis assesses the efficacy and safety of crisaborole in Chinese patients aged ≥ 2 years with mild to moderate AD.

METHODS

We evaluated the efficacy and safety of crisaborole in Chinese patients from the vehicle-controlled, phase 3 CrisADe CLEAR study. Patients were randomly assigned 2:1 to receive crisaborole or vehicle twice daily, respectively, for 28 days. The primary endpoint was percent change from baseline in Eczema Area and Severity Index (EASI) total score at day 29. Key secondary endpoints were improvement in Investigator's Static Global Assessment (ISGA), ISGA success, and change from baseline in weekly average Peak Pruritus Numerical Rating Scale (PP-NRS) score. Adverse events were documented.

RESULTS

Of 391 patients in the overall study, 237 were from China, 157 assigned to crisaborole and 80 assigned to vehicle. A greater reduction in percent change from baseline in EASI total score at day 29 was shown in the crisaborole vs. vehicle group (least squares mean [LSM]: -66.34 [95% (confidence interval) CI -71.55 to -61.12] vs. -50.18 [95% CI -58.02 to -42.34]). Response rates for achievement of ISGA improvement (43.2% [95% CI 35.4-51.1] vs. 33.4% [95% CI 22.5-44.2]) and ISGA success (31.7% [95% CI 24.3-39.0] vs. 21.5% [95% CI 12.1-30.9]) at day 29 were higher in the crisaborole vs. vehicle group. A greater reduction in change from baseline in weekly average PP-NRS score at week 4 was observed in the crisaborole vs. vehicle group (LSM: -1.98 [95% CI -2.34 to -1.62] vs. -1.08 [95% CI -1.63 to -0.53]). No new safety signals were observed.

CONCLUSION

Crisaborole was effective and well tolerated in Chinese patients aged ≥ 2 years with mild to moderate AD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04360187.

Comprehensive plasma cytokine and chemokine profiling in prurigo nodularis reveals endotypes in Type 2 inflammation

Prurigo nodularis (PN) is a chronic inflammatory skin disease that is associated with variability in peripheral blood eosinophil levels and response to T-helper 2 targeted therapies (Th2). Our objective was to determine whether circulating immune profiles with respect to type 2 inflammation differ by race and peripheral blood eosinophil count. Plasma from 56 PN patients and 13 matched healthy controls was assayed for 54 inflammatory biomarkers. We compared biomarker levels between PN and HCs, among PN patients based on absolute eosinophil count, and across racial groups in PN. Eleven biomarkers were elevated in PN versus HCs including interleukin (IL)-12/IL-23p40, tumor necrosis factor-alpha (TNF-α), Thymic stromal lymphopoietin (TSLP), and macrophage-derived chemokine (MDC/CCL22). Additionally, PN patients with AEC > 0.3 K cells/μL had higher Th2 markers (eotaxin, eotaxin-3, TSLP, MCP-4/CCL13), and African American PN patients had lower eosinophils, eotaxin, and eotaxin-3 versus Caucasian and Asian PN patients (p < 0.05 for all). Dupilumab responders had higher AEC (p < 0.01), were more likely to be Caucasian (p = 0.02) or Asian (p = 0.05) compared to African Americans, and more often had a history of atopy (p = 0.08). This study suggests that blood AEC > 0.3 K and Asian and Caucasian races are associated with Th2 skewed circulating immune profiles and response to Th2 targeted therapies.

Biosignatures of defective sebaceous gland activity in sebum-rich and sebum-poor skin areas in adult atopic dermatitis

Atopic dermatitis (AD) is a composite disease presenting disruption of the skin permeability barrier (SPB) in the stratum corneum (SC). Recent evidence supports derangement of the sebaceous gland (SG) activity in the AD pathomechanisms. The objective of this study was to delineate profiles of both sebaceous and epidermal lipids and of aminoacids from SG-rich (SGR) and SG-poor (SGP) areas in AD. Both sebum and SC were sampled from SGR areas, while SC was sampled also from SGP areas in 54 adult patients with AD, consisting of 34 and 20 subjects, respectively with and without clinical involvement of face, and in 44 age and sex-matched controls. Skin biophysics were assessed in all sampling sites. Disruption of the SBP was found to be associated with dysregulated lipidome. Abundance of sapienate and lignocerate, representing, respectively, sebum and the SC type lipids, were decreased in sebum and SC from both SGR and SGP areas. Analogously, squalene was significantly diminished in AD, regardless the site. Extent of lipid derangement in SGR areas was correlated with the AD severity. The abundance of aminoacids in the SC from SGR areas was altered more than that determined in SGP areas. Several gender-related differences were found in both controls and AD subgroups. In conclusion, the SG activity was differently compromised in adult females and males with AD, in both SGR and SGP areas. In AD, alterations in the aminoacidome profiles were apparent in the SGR areas. Lipid signatures in association with aminoacidome and skin physical properties may serve the definition of phenotype clusters that associate with AD severity and gender.

Atopic dermatitis (eczema) guidelines: 2023 American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force on Practice Parameters GRADE- and Institute of Medicine-based recommendations

BACKGROUND

Guidance addressing atopic dermatitis (AD) management, last issued in 2012 by the American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force, requires updating as a result of new treatments and improved guideline and evidence synthesis methodology.

OBJECTIVE

To produce evidence-based guidelines that support patients, clinicians, and other decision-makers in the optimal treatment of AD.

METHODS

A multidisciplinary guideline panel consisting of patients and caregivers, AD experts (dermatology and allergy/immunology), primary care practitioners (family medicine, pediatrics, internal medicine), and allied health professionals (psychology, pharmacy, nursing) convened, prioritized equity, diversity, and inclusiveness, and implemented management strategies to minimize influence of conflicts of interest. The Evidence in Allergy Group supported guideline development by performing systematic evidence reviews, facilitating guideline processes, and holding focus groups with patient and family partners. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed rating the certainty of evidence and strength of recommendations. Evidence-to-decision frameworks, subjected to public comment, translated evidence to recommendations using trustworthy guideline principles.

RESULTS

The panel agreed on 25 recommendations to gain and maintain control of AD for patients with mild, moderate, and severe AD. The eAppendix provides practical information and implementation considerations in 1-2 page patient-friendly handouts.

CONCLUSION

These evidence-based recommendations address optimal use of (1) topical treatments (barrier moisturization devices, corticosteroids, calcineurin inhibitors, PDE4 inhibitors [crisaborole], topical JAK inhibitors, occlusive [wet wrap] therapy, adjunctive antimicrobials, application frequency, maintenance therapy), (2) dilute bleach baths, (3) dietary avoidance/elimination, (4) allergen immunotherapy, and (5) systemic treatments (biologics/monoclonal antibodies, small molecule immunosuppressants [cyclosporine, methotrexate, azathioprine, mycophenolate, JAK inhibitors], and systemic corticosteroids) and UV phototherapy (light therapy).

Diversity of atopic dermatitis and selection of immune targets

Atopic dermatitis (AD) is a heterogeneous immune-mediated skin disorder affecting people of all ages and ethnicities. Despite the development of targeted therapeutics such as biologics and Janus kinase inhibitors, attaining complete clinical efficacy remains difficult. This therapeutic challenge may be attributed to the complex pathogenesis of AD. Although the TH2 axis has been extensively studied, recent advancements have started to reveal the involvement of additional immune pathways including TH1, TH17, and TH22. Understanding the interplay of these immune axes may contribute to a more personalized therapeutic approach based on patients' molecular profile, with the prospect of improving clinical outcome. This review will discuss studies exploring the molecular profile of AD in both skin and blood across age, ethnicity/race, disease chronicity, IgE levels, filaggrin mutation status, and AD association with other atopic conditions. Moreover, it will explore the potential of personalized treatment strategies based on a patient's distinct immune signature.

Incident Asthma, Asthma Exacerbations, and Asthma-Related Hospitalizations in Patients With Atopic Dermatitis

BACKGROUND

Atopic dermatitis (AD) is thought to induce asthma via the "atopic march," but the effects of AD on incident asthma and asthma severity have not been fully characterized.

OBJECTIVE

To determine risk of asthma, asthma exacerbations, and asthma-related hospitalizations among patients fwith AD.

METHODS

A cohort study was conducted using electronic health records data from UK general practices from 1994 to 2015. Children (<18 years old) and adults (≥18 years) with AD were matched on age, practice, and index date to patients without AD. AD severity was categorized using treatments and dermatologist referrals. Outcomes were incident asthma among all patients and asthma exacerbation or hospitalization among patients with asthma.

RESULTS

On comparing 409,341 children with AD (93.2% mild, 5.5% moderate, 1.3% severe) with 1,809,029 unaffected children, those with AD were found to be associated with a 2-fold greater risk of asthma compared with those without AD (hazard ratio, 1.96; 95% CI, 1.93-1.98). On comparing 625,083 adults with AD (65.7% mild, 31.4% moderate, and 2.9% severe) with 2,678,888 unaffected adults, AD was found to be associated with a 38% higher risk of asthma (hazard ratio, 1.38; 95% CI, 1.36-1.40). Asthmatic patients with AD also had a 21% to 63% greater risk of asthma exacerbations and a 20% to 64% greater risk of asthma-related hospitalizations compared with asthmatic patients without AD. Risk of asthma, asthma exacerbation, or asthma-related hospitalization increased with AD severity in a dose-dependent manner in both the pediatric and adult cohorts.

CONCLUSIONS

AD, especially in children and when more severe, is associated with greater risk of asthma as well as greater risk of asthma exacerbations and hospitalizations among asthmatic patients.

Aryl hydrocarbon receptor and IL-13 signaling crosstalk in human keratinocytes and atopic dermatitis

Introduction

Atopic dermatitis (AD) is an allergic skin disease mediated by skin barrier impairment and IL-13-driven immune response. Activation of the aryl hydrocarbon receptor (AHR) has shown promise in early clinical trials for AD; however, the mechanism by which AHR partially ameliorates AD is not well known.

Methods

Gene expression data from human biopsies were analyzed, and compared to gene expression from RNA-sequencing in our in-vitro HaCaT cell model system. Western blot, ELISA qRT-PCR were used to further explore the relationship between AHR and IL-13 signaling in HaCaT cells.

Results

The AHR target gene CYP1A1 was decreased in lesional skin compared with healthy control skin (p = 4.30 × 10-9). Single-cell RNA sequencing (scRNAseq) demonstrated increased AHR expression (p < 1.0 × 10-4) and decreased CYP1A1 expression in lesional AD keratinocytes compared with healthy control keratinocytes (p < 0.001). Activation of AHR by AHR agonists in HaCaT cells reversed IL-13-dependent gene expression of several key genes in AD pathogenesis, most notably the eosinophil chemoattractant CCL26 (eotaxin-3). Differentially expressed genes in keratinocytes of patients with AD substantially overlapped with genes regulated by AHR agonists from HaCaT cells by RNAseq, but in reverse direction. Mechanistically, there was evidence for direct transcriptional effects of AHR; AHR binding motifs were identified in the differentially expressed genes from lesional AD keratinocytes compared to control keratinocytes, and AHR activation did not modify IL-13-dependent signal transducer and activator of transcription 6 (STAT6) translocation to the nucleus.

Discussion

Together, these data suggest that the AHR pathway is dysregulated in AD and that AHR modulates IL-13 downstream signaling in keratinocytes through genome-wide, transcriptional regulatory effects.

Rural and urban exposures shape early life immune development in South African children with atopic dermatitis and nonallergic children

BACKGROUND

Immunological traits and functions have been consistently associated with environmental exposures and are thought to shape allergic disease susceptibility and protection. In particular, specific exposures in early life may have more significant effects on the developing immune system, with potentially long-term impacts.

METHODS

We performed RNA-Seq on peripheral blood mononuclear cells (PBMCs) from 150 children with atopic dermatitis and healthy nonallergic children in rural and urban settings from the same ethnolinguistic AmaXhosa background in South Africa. We measured environmental exposures using questionnaires.

RESULTS

A distinct PBMC gene expression pattern was observed in those children with atopic dermatitis (132 differentially expressed genes [DEGs]). However, the predominant influences on the immune cell transcriptome were related to early life exposures including animals, time outdoors, and types of cooking and heating fuels. Sample clustering revealed two rural groups (Rural_1 and Rural_2) that separated from the urban group (3413 and 2647 DEGs, respectively). The most significantly regulated pathways in Rural_1 children were related to innate activation of the immune system (e.g., TLR and cytokine signaling), changes in lymphocyte polarization (e.g., TH17 cells), and immune cell metabolism (i.e., oxidative phosphorylation). The Rural_2 group displayed evidence for ongoing lymphocyte activation (e.g., T cell receptor signaling), with changes in immune cell survival and proliferation (e.g., mTOR signaling, insulin signaling).

CONCLUSIONS

This study highlights the importance of the exposome on immune development in early life and identifies potentially protective (e.g., animal) exposures and potentially detrimental (e.g., pollutant) exposures that impact key immunological pathways.

How Do Classical Subtypes Correspond to Endotypes in Atopic Dermatitis?

Since atopic dermatitis (AD) is a heterogeneous condition, the subtyping of AD is a crucial issue. The classical subtypes of AD are represented by extrinsic and intrinsic subtypes, European-American and Asian subtypes, and adult and pediatric subtypes. While the subtyping of AD was historically conducted based on the phenotype, recent findings on the mechanisms of AD have revealed the importance of the endotype, which can characterize individual patients more accurately. Considering the current development of AD therapies, AD endotyping is a prerequisite for a personalized therapeutic choice. Endotypes of AD can be stratified from different viewpoints, including cytokine expression patterns, allergen properties, epidermal barrier conditions, ceramide variation, the involvement of innate immunity, and serum biomarkers. Among them, the cytokine-based endotype seems to be the most useful one and is categorized into type 2 cytokine (IL-4, IL-13 and IL-31)-high, type 1 cytokine (IFN-γ)-high, and/or type 3 cytokine (IL-22 and IL-17)-high, or mixed subtypes. Recently proposed biomarker endotyping aims at individualized treatment options, although the daily clinical use of endotypes is a future issue. To better understand the endotypes for clinicians, attempts to adjust each of the classical subtypes to endotypes are required. This review will discuss the correspondence of the classical subtypes to the various endotypes that have recently been proposed.

Serum thymic stromal lymphopoietin (TSLP) levels in atopic dermatitis patients: a systematic review and meta-analysis

Thymic stromal lymphopoietin (TSLP) is critical in developing allergic responses, including atopic dermatitis (AD). We systematically reviewed the literature to complete a meta-analysis to quantitatively summarize the levels of serum TSLP in AD. The study was prospectively registered in the PROSPERO database (ID = CRD42021242628). The PUBMED, SCOPUS, and Cochrane Library databases were reviewed, and original articles investigating serum TSLP in AD patients were included. Differences in TSLP levels of AD patients and controls were summarized by standardized mean differences (SMD) using a random effects model. Study quality was assessed by applying the Newcastle‒Ottawa Scale. Fourteen studies, which included 1,032 AD patients and 416 controls, were included. Meta-analysis showed that TSLP levels were significantly higher in the AD group than in the control group (SMD = 2.21, 95% CI 1.37-3.06, p < 0.001). Stratification by geographical region, age, disease severity, TSLP determination method, sample size, and study quality revealed significantly elevated TSLP levels in European AD patients (SMD = 3.48, 95% CI 1.75-5.21, p < 0.0001), adult AD patients (SMD = 4.10, 95% CI 2.00-6.21, p < 0.0001), child AD patients (SMD = 0.83, 95% CI 0.08-1.59, p = 0.031), and all severity groups with AD compared with the control group (mild: SMD = 1.15, 95% CI 0.14-2.16, p = 0.025; moderate: SMD = 2.48, 95% CI 0.33-4.62, p = 0.024; and severe: SMD = 8.28, 95% CI 4.82-11.74, p = 2.72e-6). Noticeably, adults showed higher serum TSLP levels than children with AD, and serum TSL levels increased according to AD severity. In conclusion, our meta-analysis demonstrates that circulating TSLP levels are elevated in patients with AD. Future studies are warranted to further elucidate the sources of heterogeneity.

European and multi-ancestry genome-wide association meta-analysis of atopic dermatitis highlights importance of systemic immune regulation

Atopic dermatitis (AD) is a common inflammatory skin condition and prior genome-wide association studies (GWAS) have identified 71 associated loci. In the current study we conducted the largest AD GWAS to date (discovery N = 1,086,394, replication N = 3,604,027), combining previously reported cohorts with additional available data. We identified 81 loci (29 novel) in the European-only analysis (which all replicated in a separate European analysis) and 10 additional loci in the multi-ancestry analysis (3 novel). Eight variants from the multi-ancestry analysis replicated in at least one of the populations tested (European, Latino or African), while two may be specific to individuals of Japanese ancestry. AD loci showed enrichment for DNAse I hypersensitivity and eQTL associations in blood. At each locus we prioritised candidate genes by integrating multi-omic data. The implicated genes are predominantly in immune pathways of relevance to atopic inflammation and some offer drug repurposing opportunities.

Atopic Dermatitis Across Shades of Skin

Atopic dermatitis (AD) is a chronic, heterogeneous inflammatory skin disease that is associated with immense patient burden globally. There is increasing appreciation of disparities among patients identified as having skin of color (SOC), which often refers to patients of non-White race or non-European ancestry, but can broadly include individuals from a number of different racial, ethnic, ancestral, and skin pigmentation groups based on definition. In this narrative review, we discuss key terminology as it relates to AD across shades of skin, including modern definitions of 'race', 'ethnicity', and 'SOC'. We then synthesize the current literature describing disparities in AD prevalence, disease recognition, and burden alongside current data regarding genetic and immunologic findings across SOC populations. In the context of these findings, we highlight key concomitant social determinants of health, including environmental factors, socioeconomic status, and access to care, for which race often serves as a proxy for true biological and genetic differences. Finally, we discuss future efforts to shift to a more inclusive understanding of AD to encompass all shades of skin, to ensure equitable representation of diverse populations in high impact research, and intensify efforts to address the critical upstream factors driving observed disparities.

Disorders in Children

Pediatric dermatoses can present at birth or develop over time. When managing dermatology conditions in children, caregiver involvement is important. Patients may have lesions that need to be monitored or need assistance with therapeutic administration. The following section provides a subset of pediatric dermatoses and notable points for presentation in skin of color patients. Providers need to be able to recognize dermatology conditions in patients of varying skin tones and provide therapies that address the condition and any associated pigmentary alterations.

Ethnicity, Race and Skin Color: Challenges and Opportunities for Atopic Dermatitis Clinical Trials

The number of clinical trials conducted in patients with atopic dermatitis is increasing steadily. These trials are conducted in several countries across all continents and include patients of different ethnicity, race and skin color. This diversity is desired, but it also brings challenges, including the diagnosis and evaluation of disease severity in patients with different skin colors; the influence of ethnicity on the perception of quality of life and patient reported outcomes; the inclusion of ethnicities that are only present in one country or that live far from clinical research sites; and the reporting of drug safety information. There is a need to better train physicians on the evaluation of atopic dermatitis in patients with different skin colors and a need to improve the systematic reporting of ethnicity, race and skin color in clinical trial publications.

Atopic Dermatitis in Latin America: Considerations on Epidemiology, Clinical and Laboratory Features, Ethnic/Racial Variations, and Therapeutic Management

Latin America (LA) encompasses about 8.5% of the world's population, exhibits ethnic/racial heterogeneity and social inequality. We hereby present a 20-year literature review (2004-2023) on epidemiology, diagnosis, clinical and laboratory features, quality of life and management of atopic dermatitis (AD) in LA. Highest AD prevalence for children aged 6-7 years was reported in Ecuador (22.5%) and Colombia (20.9%), for adolescents in Colombia (24.6%) and for all ages, in Brazil (20.1%). Regions with a predominantly Black population in LA varied significantly, ranging from 4.4% in Northern Brazil to 10.1% in Cuba, indicating genetic variation among African subgroups. Filaggrin loss-of-function mutations showed variants seen in Europeans in 9.3% of Chilean patients and studies in Brazil revealed impaired expression of filaggrin and claudin-1 in the skin but increased expression in conjunctival epithelia of AD patients. The most reported AD features included erythema, pruritus, and dry skin, with marked lichenification. Severe pruritus was reported by 54.4% of patients and a high impact on quality of life was detected in 50% of adults with AD. In Brazilian referral hospitals, 65.6% of patients were classified as having severe AD, and 56% had one or more hospitalizations during their lifetime, indicating a need for better disease control. Diagnosing AD is challenging due to broad clinical features, ethnoracial variations and lack of universal diagnostic criteria. Furthermore, lack of physician training, barriers to medication access, and socioeconomic inequalities hinder effective disease management in LA.

Maintained Improvement in Physician- and Patient-Reported Outcomes with Baricitinib in Adults with Moderate-to-Severe Atopic Dermatitis who were Treated for up to 104 Weeks in a Randomized Trial

Patients who completed the originating studies, BREEZE-AD1 (NCT03334396), BREEZE-AD2 (NCT03334422), and BREEZE-AD7 (NCT03733301), were eligible for enrolment in the multicentre, phase 3, long-term extension study BREEZE-AD3 (NCT03334435). At week 52, responders and partial responders to baricitinib 4 mg were re-randomized (1:1) into the sub-study to dose continuation (4 mg, N = 84), or dose down-titration (2 mg, N = 84).Maintenance of response was assessed from week 52 to 104 of BREEZE-AD3. Physician-rated outcomes included vIGA-AD (0,1), EASI75, and mean change from baseline in EASI. Patient-reported outcomes included DLQI, POEM total score, HADS, and from baseline: WPAI (presenteeism, absenteeism, overall work impairment, daily activity impairment) and change from baseline in SCORAD itch and sleep loss.With continuous treatment with baricitinib 4 mg, efficacy was maintained up to week 104 in vIGA-AD (0,1), EASI75, EASI mean change from baseline, SCORAD itch, SCORAD sleep loss, DLQI, POEM, HADS, and WPAI (all scores). Patients down-titrated to 2 mg maintained most of their improvements in each of these measures.The sub-study of BREEZE AD3 supports flexibility in baricitinib dosing regimens. Patients who continued treatment with baricitinib 4 mg and down-titrated to 2 mg maintained improvements in skin, itch, sleep, and quality of life for up to 104 weeks.

Causal association between atopic eczema and inflammatory bowel disease: A two-sample bidirectional Mendelian randomization study of the East Asian population

Observation studies have postulated that atopic eczema is associated with a risk of inflammatory bowel disease in the East Asian population; however, this association does not obviate the biases resulting from confounding effects and reverse causation. This study aimed to determine whether this association is causal in the East Asian population using a bidirectional two-sample Mendelian randomization design. Independent genetic variants obtained from public genome-wide association studies for atopic eczema (4296 cases, 163 807 controls) were extracted to estimate the causal effects on inflammatory bowel disease (2824 cases, 3719 controls) and its two main conditions: Crohn's disease (1690 cases, 3719 controls) and ulcerative colitis (1134 cases, 3719 controls). Atopic eczema was found to be strongly associated with inflammatory bowel disease (odds ratio [95% confidence interval]: 1.520 [1.179, 1.959]; p = 0.001), but not vice versa. Subtype analyses revealed that atopic eczema is significantly associated with Crohn's disease (1.650 [1.293, 2.106]; p = 0.000) but not with ulcerative colitis. Both Crohn's disease and ulcerative colitis were found to be causally related to atopic eczema; Crohn's disease could reduce the risk of atopic eczema (0.866 [0.807, 0.930]; p = 0.000) while ulcerative colitis could increase the risk of atopic eczema (1.112 [1.021, 1.212]; p = 0.015). In conclusion, this study revealed that statistically causal relationships are present between atopic eczema and inflammatory bowel disease in the East Asian population. These findings are significant for guiding the treatment of atopic eczema and inflammatory bowel disease in clinical practice.

Comparison of real-world treatment outcomes of systemic immunomodulating therapy in atopic dermatitis patients with dark and light skin types

Background

Few data exist on differences in treatment effectiveness and safety in atopic dermatitis patients of different skin types.

Objective

To investigate treatment outcomes of dupilumab, methotrexate, and ciclosporin, and morphological phenotypes in atopic dermatitis patients, stratified by Fitzpatrick skin type.

Methods

In an observational prospective cohort study, pooling data from the Dutch TREAT (TREatment of ATopic eczema) NL (treatregister.nl) and UK-Irish A-STAR (Atopic eczema Systemic TherApy Register; astar-register.org) registries, data on morphological phenotypes and treatment outcomes were investigated.

Results

A total of 235 patients were included (light skin types [LST]: Fitzpatrick skin type 1-3, n = 156 [Ethnicity, White: 94.2%]; dark skin types [DST]: skin type 4-6, n = 68 [Black African/Afro-Caribbean: 25%, South-Asian: 26.5%, and Hispanics: 0%]). DST were younger (19.5 vs 29.0 years; P < .001), more often had follicular eczema (22.1% vs 2.6%; P < .001), higher baseline Eczema Area and Severity Index (EASI) scores (20.1 vs 14.9; P = .009), less allergic contact dermatitis (30.9% vs 47.4%; P = .03), and less previous phototherapy use (39.7% vs 59.0%; P = .008). When comparing DST and LST corrected for covariates including baseline EASI, DST showed greater mean EASI reduction between baseline and 6 months with only dupilumab (16.7 vs 9.7; adjusted P = .032). No differences were found for adverse events for any treatments (P > .05).

Limitations

Unblinded, non-randomized.

Conclusion

Atopic dermatitis differs in several characteristics between LST and DST. Skin type may influence treatment effectiveness of dupilumab.

Efficacy and Safety of Dupilumab Maintained in Adults ≥ 60 Years of Age with Moderate-to-Severe Atopic Dermatitis: Analysis of Pooled Data from Four Randomized Clinical Trials

BACKGROUND

Adults aged ≥ 60 years are often underrepresented in atopic dermatitis (AD) clinical trials; age-related comorbidities may impact treatment efficacy and safety.

OBJECTIVE

The aim was to report dupilumab efficacy and safety in patients aged ≥ 60 years with moderate-to-severe AD.

METHODS

Data were pooled from four randomized, placebo-controlled dupilumab trials of patients with moderate-to-severe AD (LIBERTY AD SOLO 1 and 2, LIBERTY AD CAFÉ, and LIBERTY AD CHRONOS) and stratified by age (< 60 [N = 2261] and ≥ 60 [N = 183] years). Patients received dupilumab 300 mg every week (qw) or every 2 weeks (q2w), or placebo with/without topical corticosteroids. Post hoc efficacy at week 16 was examined using broad categorical and continuous assessments of skin lesions, symptoms, biomarkers, and quality of life. Safety was also assessed.

RESULTS

In the ≥ 60-year-old group at week 16, a greater proportion of dupilumab-treated patients achieved an Investigator's Global Assessment score of 0/1 (q2w: 44.4%; qw: 39.7%) and 75% improvement in Eczema Area and Severity Index (63.0%; 61.6%) versus placebo (7.1% and 14.3%, respectively; P < 0.0001). Type 2 inflammation biomarkers (immunoglobulin E and thymus and activation-regulated chemokine) were also significantly reduced in dupilumab- versus placebo-treated patients (P < 0.01). Results were similar in the < 60-year-old group. The exposure-adjusted incidences of adverse events in dupilumab-treated patients were generally similar to those receiving placebo, with numerically fewer treatment-emergent adverse events in the dupilumab-treated ≥ 60-year-old group versus placebo.

LIMITATIONS

There were fewer patients in the ≥ 60-year-old group; post hoc analyses.

CONCLUSION

Dupilumab improved AD signs and symptoms in patients aged ≥ 60 years; results were comparable to those in patients aged < 60 years. Safety was consistent with the known dupilumab safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02277743, NCT02277769, NCT02755649, NCT02260986. Does dupilumab benefit adults aged 60 years and older with moderate-to-severe atopic dermatitis?(MP4 20,787 KB).

Oral Janus kinase inhibitors for atopic dermatitis

Atopic dermatitis (AD) is one of the most common inflammatory skin conditions. The pathogenesis of AD involves skin barrier disruption and immune activation of T-helper (T_H)2 and T_H22 and varying degrees of T_H1 and T_H17 activation in various patient subtypes. Although AD is mainly driven by T_H2, the molecular and clinical heterogeneity of AD underscores the need for more efficacious treatments that target multiple immune axes. Janus kinase (JAK) inhibitors are novel therapeutics that broadly block many AD-related proinflammatory cytokines (interleukin [IL]-4, IL-5, IL-13, IL-31, thymic stromal lymphopoietin, interferon gamma, IL-12, IL-23, IL-17) across different immune pathways. Oral JAK inhibitors have been found to be efficacious in AD, with 2 (abrocitinib and upadacitinib) recently gaining US Food and Drug Administration approval and several others under investigation in clinical trials with promising results. These systemic agents have surpassed conventional thresholds of treatment response, with many patients achieving complete or almost complete skin clearance, and provide a fast-acting alternative therapy for patients who are not responsive to biologics or other conventional therapies. However, systemic JAK inhibitors come with health concerns, requiring additional long-term clinical trials to characterize their safety profile in patients with AD. This review summarizes the current literature on the safety and efficacy of oral JAK inhibitors in AD and discusses future directions for research.

Prenatal Maternal Risk Factors Contributing to Atopic Dermatitis: A Systematic Review and Meta-Analysis of Cohort Studies

BACKGROUND

The gestational risk factors predispose to the manifestation of early childhood atopic dermatitis (AD).

OBJECTIVE

We evaluated the association between modifiable and non-modifiable gestational and prenatal risk factors that affect the AD prevalence in children.

METHODS

We performed the systematic review and meta-analysis of cohort studies (n=27) in PubMed and EMBASE (2000~2021). A meta-analysis was performed using random-effects models to estimate pooled odds ratios (OR) or hazard ratio (HR). We performed a systematic review according to Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines and summarized cohort studies investigating gestational and prenatal risk factor those predispose to AD in off spring. Leading modifiable and non-modifiable were identified through ORs. Meta-analysis using the random effect model was also conducted to provide an overall estimate for several significant factors.

RESULTS

Among the non-modifiable risk factors gestational diabetes (7.2, 95% confidence interval [CI]: 1.4~34.5), maternal history of allergy (2.14, 95% CI: 1.54~2.97) and prenatal history of eczema (2.46, 95% CI: 1.0~5.8) were found as major determining risk factors in early manifestation of AD in children. Further, maternal exposure to industrial products (1.89, 95% CI: 1.10~3.16), exposure to antibiotics during pregnancy (3.59, 95% CI: 1.19~10.85) and passive smoking during pregnancy (2.60, 95% CI: 1.11~6.1) are leading causes of early AD manifestation.

CONCLUSION

Conclusively, both genetic and environmental factors play a pivotal role in early manifestation of AD. The better managing the environmental factors during gestational phase to the least can help curtail the prevalence of AD in children.

Association of KIR2DL5, KIR2DS5, and KIR2DS1 allelic variation and atopic dermatitis

Natural killer cells (NK) have been associated with the pathophysiology of atopic dermatitis (AD). NK function is regulated by killer cell Ig-like receptor family (KIR) receptors that interact with HLA ligands. The study goal was to focus on allelic variation in genes KIR2DL5, KIR2DS5, and KIR2DS1 with respect to AD. This was a case-control study of individuals with (n = 313) and without (n = 176) AD. Associations were estimated using logistic regression. The prevalence of KIR2DL5 was 52.5% (95% CI 48.0,57.0), KIR2DS5 was 33.0% (28.8,37.3), and KIR2DS1 was 33.6% (29.4,38.0). The presence of the KIR2DL5*001:01 increased the odds of having AD by about 86% (odds ratio (OR): 1.86(1.23,2.82) p = 0.003). The risk for individuals homozygous for KIR2DL5*001:01 was even greater (OR: 2.16 (95% CI 1.31,3.53) p = 0.0023). The odds of having AD with KIR2DL5*001:01 was similar in Whites and Blacks. Allelic variation in KIR2DS5 and KIR2DS1 was not associated with AD. There is no known HLA binding ligand for KIR2DL5. The effect of KIR2DL5*001:01 increased in the presence of HLA-B*-21TT leader sequence (2.46(1.37,4.41) p = 0.0025) and the HLA-C2 ligand (2.07 (1.37,4.41, p = 0.000002). Our study shows an independent association of the KIR2DL5*001:01 with AD and is the first study to associate AD with KIR allelic variation.

IL-4Rα signalling in B cells and T cells play differential roles in acute and chronic atopic dermatitis

Atopic dermatitis (AD) is a common pruritic inflammatory skin disease with complex environmental and genetic predisposing factors. Primary skin barrier dysfunction and aberrant T helper 2 (TH2) responses to common allergens, together with increased serum IgE antibodies, characterise the disease. B and T cells are essential in the disease manifestation, however, the exact mechanism of how these cells is involved is unclear. Targeting interleukin 4 receptor alpha (IL-4Rα), an IL-4/IL-13 signalling axis, with dupilumab shows efficacy in AD. We investigated the importance of IL-4Rα signalling specifically on B and T cells during acute and chronic models of AD. We used House dust mite (HDM) and Ovalbumin (OVA) in chronic models and a low-calcemic analog of vitamin D (MC903) for acute models of AD. We used mb1creIL-4Rα-/lox, iLCKcreIL-4Rα-/lox, LCKcreIL-4Rα-/lox, CD4creIL-4Rα-/lox, Foxp3creIL-4Rα-/lox and IL-4Rα-/lox littermate controls. IL-4Rα-responsive B cells were essential in serum IgE levels, but not in epidermal thickening in both chronic and acute models. IL-4Rα-responsive T cells were essential in epidermal thickening in the pan-T cell, but not CD4 or CD8 T cells suggesting the importance of γδT cells during acute AD. Our results suggest that IL-4Rα responsiveness on innate T cells regulates acute atopic dermatitis, while on B cells it regulates IgE.

Safety and Efficacy of Upadacitinib for Atopic Dermatitis in Japan: 2-Year Interim Results from the Phase 3 Rising Up Study

INTRODUCTION

Upadacitinib, an oral, selective Janus kinase inhibitor, is approved in Japan for the treatment of moderate-to-severe atopic dermatitis (AD), a chronic inflammatory skin disease characterized by eczematous morphology and intense itch.

METHODS

Rising Up is an ongoing phase 3, randomized, multicenter study evaluating the long-term safety and efficacy of upadacitinib in Japan. Patients with moderate-to-severe AD were randomized 1:1:1 to topical corticosteroids plus upadacitinib 15 mg (UPA15), upadacitinib 30 mg (UPA30), or placebo at baseline; at week 16, placebo patients were rerandomized 1:1 to UPA15 or UPA30 (plus topical corticosteroids per investigator discretion). This 2-year interim analysis evaluated safety and efficacy through 112 weeks (data cutoff date: 11 August 2021). Adverse events (AEs), AEs of special interest (AESIs), and laboratory data were assessed. Efficacy assessments included ≥ 75% and ≥ 90% improvement from baseline in Eczema Area and Severity Index (EASI 75/90), achievement of clear or almost clear on the validated Investigator Global Assessment for Atopic Dermatitis (vIGA-AD 0/1), and ≥ 4-point improvement in the Worst Pruritus Numerical Rating Scale (WP-NRS).

RESULTS

A total of 272 patients were enrolled and 242 were ongoing at data cutoff (UPA15, n = 120; UPA30, n = 122). After 112 weeks of treatment, serious AEs, AEs leading to discontinuation, and most AESIs were generally infrequent, and rates were similar between the two upadacitinib groups. One event each of rectal cancer and cerebellar hemorrhage was reported in the UPA15 group; no thrombosis events were observed. The most common AEs included acne, nasopharyngitis, and herpes zoster. EASI 75, EASI 90, vIGA-AD 0/1, and WP-NRS response rates were maintained through week 112.

CONCLUSION

UPA15 and UPA30 were well tolerated through 112 weeks of treatment with similar safety profiles to short-term studies and demonstrated durable long-term efficacy for the treatment of moderate-to-severe AD in adults and adolescents.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03661138.

Dupilumab Treatment in Adults with Moderate-to-Severe Atopic Dermatitis is Efficacious Regardless of Age of Disease Onset: a Post Hoc Analysis of Two Phase 3 Clinical Trials

INTRODUCTION

Adults with atopic dermatitis (AD) commonly report adult-onset disease. AD is associated with different genetics, lesion morphology and distribution, and symptoms by age of onset. Yet little is known about possible differences in treatment efficacy between adults with adult-onset or childhood-onset AD.

METHODS

We evaluated the efficacy of dupilumab by age of AD onset in adults with moderate-to-severe AD, using pooled data from the LIBERTY AD SOLO 1 and 2 studies (NCT02277743, NCT02277769). Results were stratified based on self-reported age of AD onset, divided into four age subgroups: 0-4, 5-9, 10-19, and over 20 years.

RESULTS

This analysis included 460 patients treated with placebo and 457 treated with dupilumab 300 mg every 2 weeks (q2w), with a mean patient age of 38 years. Most patients (53.2%) reported AD onset at 0-4 years, with 14% at 5-9 years, 13.4% at 10-19 years, and 18.5% at 20 years or older. Dupilumab significantly improved AD signs and symptoms over 16 weeks compared with placebo, regardless of age of onset. Dupilumab treatment resulted in a significantly greater proportion of patients achieving Eczema Area and Severity Index (EASI)-50, EASI-75, and EASI-90 (50%, 75%, and 90% improvement from baseline EASI, respectively), and clear or almost clear skin (Investigator's Global Assessment score 0 or 1) across all age-of-onset subgroups compared with placebo. In addition, EASI improvements were significant across all anatomical regions in all subgroups. Weekly average peak pruritus Numerical Rating Scale and Dermatology Life Quality Index also improved consistently and significantly with dupilumab versus placebo, regardless of age of onset.

CONCLUSION

Despite possible differences in presentation and progression of AD linked to age of onset, dupilumab showed similar significant and sustained improvements in AD signs, symptoms, and quality of life in adults compared with placebo, over 16 weeks of treatment.

TRIAL REGISTRATION

LIBERTY AD SOLO 1: NCT02277743; LIBERTY AD SOLO 2: NCT02277769. Infographic available for this article.

Elevation of IgE in patients with psoriasis: Is it a paradoxical phenomenon?

Immunoglobulin E (IgE) elevation is a hallmark of allergic conditions such as atopic dermatitis (AD). The pathogenesis of AD is typically associated with high levels of IL-4 and IL-13 produced by activated T helper 2 (Th2) cells. Psoriasis, on the other hand, is an inflammatory skin disease mainly driven by Th17 cells and their related cytokines. Although the immunopathologic reactions and clinical manifestations are often easily distinguished in the two skin conditions, patients with psoriasis may sometimes exhibit AD-like manifestations, such as elevated IgE and persistent pruritic lesions. Given the fact that the effective T cells have great plasticity to re-differentiate in response to innate and environmental factors, this unusual skin condition could be a consequence of a cross-reaction between distinct arms of T-cell and humoral immunity. Here we review the literature concerning the roles of IgE in the development of AD and psoriasis, showing that elevated IgE seems to be an important indicator for this non-typical psoriasis.

Photosensitivity is an important cause of refractory facial erythema in atopic dermatitis: A retrospective study of 82 Chinese patients

BACKGROUND

Ultraviolet radiation can aggravate facial erythema in atopic dermatitis (AD) patients.

OBJECTIVE

To investigate the photobiological testing results of Chinese AD patients with refractory facial erythema.

METHODS

We conducted a retrospective analysis of 82 AD patients with refractory facial erythema who visited our department during 2004-2021. All of them completed phototesting and photopatch testing.

RESULTS

82 patients were enrolled in the study, and 53 (64.6%) were between 18 and 30 years old. 51.2% (42/82) had positive phototesting results and were considered photosensitive AD (PhAD) patients. One-third of them were both allergic to ultraviolet A and ultraviolet B. 65.9% (54/82) suffered from photoallergic contact dermatitis. Chlorpromazine (50.7%), potassium dichromate (13.2%), and thimerosal (11.8%) were the top three common photoallergens. Overall, 86.3% of AD patients with refractory facial erythema had direct photoallergy or photocontact allergy. PhAD patients had fewer allergic comorbidities than the other group (p = .007). More non-PhAD patients (55.0%) suffered from AD at 2-14 years old (p = .015).

CONCLUSIONS

Photosensitivity contributes a lot to the facial lesions of AD patients, especially in their 20s. 86.3% of these patients had direct photoallergy or photocontact allergy. Therefore, AD patients with facial erythema should undergo phototesting and photopatch testing routinely.

Portulaca oleracea L. extracts alleviate 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is a common chronic allergic skin disease characterized clinically by severe skin lesions and pruritus. Portulaca oleracea L. (PO) is a resourceful plant with homologous properties in medicine and food. In this study, we used two different methods to extract PO, and compared the therapeutic effects of PO aqueous extract (POAE) and PO ultrasound-assisted ethanol extract (POEE) on 2,4-dinitrochlorobenzene (DNCB)-induced AD mice. The results showed that in POAE and POEE, the extraction rates of polysaccharides were 16.95% and 9.85%, while the extraction rates of total flavonoids were 3.15% and 3.25%, respectively. Compared with AD mice, clinical symptoms such as erythema, edema, dryness and ulceration in the back and left ear were alleviated, and pruritus behavior was reduced after POAE and POEE treatments. The thickness of the skin epidermis was thinned, the density of skin nerve fibers labeled with protein gene product 9.5 (PGP9.5) was decreased, and mast cell infiltration was reduced. There was a decrease in blood lymphocytes, eosinophils and basophils, a significant decrease in spleen index and a noticeable decrease in serum immunoglobulin E (Ig E). POEE significantly reduced the concentration of the skin pruritic factor interleukin (Il)-31. POAE and POEE reduced the concentration of skin histamine (His), down-regulated mRNA expression levels of interferon-γ (Ifnγ), tumor necrosis factor-α (Tnf-α), thymic stromal lymphopoietin (Tslp) and Il-4, with an increase of Filaggrin (Flg) and Loricrin (Lor) in skin lesions. These results suggested that POAE and POEE may inhibit atopic response and alleviate the clinical symptoms of AD by inhibiting the expression of immune cells, inflammatory mediators and cytokines. PO may be a potential effective drug for AD-like diseases.

Atopic Dermatitis: Striving for Reliable Biomarkers

Atopic dermatitis (AD) is a highly heterogeneous inflammatory disease regarding both its pathophysiology and clinical manifestations. However, it is treated according to the “one-size-fits-all” approach, which may restrict response to treatment. Thus, there is an unmet need for the stratification of patients with AD into distinct endotypes and clinical phenotypes based on biomarkers that will contribute to the development of precision medicine in AD. The development of reliable biomarkers that may distinguish which patients with AD are most likely to benefit from specific targeted therapies is a complex procedure and to date none of the identified candidate biomarkers for AD has been validated for use in routine clinical practice. Reliable biomarkers in AD are expected to improve diagnosis, evaluate disease severity, predict the course of disease, the development of comorbidities, or the therapeutic response, resulting in effective and personalized treatment of AD. Among the studied AD potential biomarkers, thymus and activation-regulated chemokine/C-C motif ligand 17 (TARC/CCL17) has the greatest evidence-based support for becoming a reliable biomarker in AD correlated with disease severity in both children and adults. In this review, we present the most prominent candidate biomarkers in AD and their suggested use.

IgG from Adult Atopic Dermatitis (AD) Patients Induces Thymic IL-22 Production and CLA Expression on CD4+ T Cells: Possible Epigenetic Implications Mediated by miRNA

Atopic dermatitis (AD) is a common relapsing inflammatory skin disorder characterized by immune-mediated inflammation and epidermal barrier dysfunction. The pathogenesis of AD is multifactorial and has not been fully elucidated to date. This study aimed to evaluate whether serum IgG from adult AD patients could modulate the thymic maturation of IL-22-producing T cells and CLA+ T cells of non-atopic infants. Given that miRNAs regulate immune response genes, we evaluated whether miRNA expression is also altered in cultured thymocytes. Thymocytes were cultured with purified IgG from AD patients or control conditions (mock, Intravenous-IgG (IVIg), non-atopic IgG, or atopic non-AD IgG). Using flow cytometry analysis, we assessed the expression of CLA and intracellular levels of IL-4, IFN-γ, and IL-22 on double-positive T cells (DP T), CD4 T cells, or CD8 T cells. We also investigated the frequency of IgG isotypes and their direct interaction with the thymic T cells membrane. The miRNA profiles were evaluated by the Illumina small RNA-seq approach. MiRNA target gene prediction and enrichment analyses were performed using bioinformatics. Increased frequencies of IL-22 and CLA+ producing CD4+ T cells cultured with IgG of AD patients was seen in non-atopic infant thymocytes compared to all control conditions. No alterations were observed in the frequency of IgG isotypes among evaluated IgG pools. Evidence for a direct interaction between IgG and thymic DP T, CD4 T, and CD8 T cells is presented. The small RNA-seq analysis identified ten mature miRNAs that were modulated by AD IgG compared to mock condition (miR-181b-5p, hsa-miR-130b-3p, hsa-miR-26a-5p, hsa-miR-4497, has-miR-146a, hsa-let-7i-5p, hsa-miR-342-3p, has-miR-148a-3p, has-miR-92a and has-miR-4492). The prediction of the targetome of the seven dysregulated miRNAs between AD and mock control revealed 122 putative targets, and functional and pathway enrichment analyses were performed. Our results enhance our understanding of the mechanism by which IgG can collaborate in thymic T cells in the setting of infant AD.

Immunological Pathomechanisms of Spongiotic Dermatitis in Skin Lesions of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic pruritic skin disease with a complex pathogenesis underlying its heterogeneous clinical phenotypes and endotypes. The skin manifestation of AD reflects the cytokine milieu of a type-2-dominant immunity axis induced by genetic predisposition, innate immunity dysregulation, epidermal barrier defects, and allergic inflammation. However, the detailed pathomechanism of eczematous dermatitis, which is the principal characteristic of AD, remains unclear. This review examines previous studies demonstrating research progress in this area and considers the immunological pathomechanism of “spongiotic dermatitis”, which is the histopathological hallmark of eczematous dermatitis. Studies in this field have revealed the importance of IgE-mediated delayed-type hypersensitivity, the Fas/Fas-ligand system, and cell-mediated cytotoxicity in inducing the apoptosis of keratinocytes in spongiotic dermatitis. Recent studies have demonstrated that, together with infiltrating CD4 T cells, IgE-expressing dendritic cells (i.e., inflammatory dendritic epidermal cells and Langerhans cells) that capture specific allergens (i.e., house dust mites) are present in the spongiotic epidermis of lichenified eczema in patients with IgE-allergic AD. These findings suggest that IgE-mediated delayed-type hypersensitivity plays a pivotal role in the pathogenesis of spongiotic dermatitis in the skin lesions of AD.

Atopic dermatitis: pathomechanisms and lessons learned from novel systemic therapeutic options

Atopic dermatitis (AD) is a chronic, heterogenous, inflammatory skin disorder associated with a high skin-related health burden, typically starting in childhood and often persisting into adulthood. AD is characterized by a wide range of clinical phenotypes, reflecting multiple underlying pathophysiological mechanisms and interactions between genetics, immune system dysregulation, and environmental factors. In this review, we describe the diverse cellular and molecular mechanisms involved in AD, including the critical role of T cell-driven inflammation, primarily via T helper (Th) 2- and Th17-derived cytokines, many of which are mediated by the Janus kinase (JAK) signaling pathway. These local inflammatory processes interact with sensory neuronal pathways, contributing to the clinical manifestations of AD, including itch, pain, and sleep disturbance. The recent elucidation of the molecular pathways involved in AD has allowed treatment strategies to evolve from broad-acting systemic immunosuppressive therapies to more targeted agents, including JAK inhibitors and cytokine-specific biologic agents. Evidence from the clinical development of these targeted therapies has reinforced and expanded our understanding of the pathophysiological mechanisms underlying AD and holds promise for individualized treatment strategies tailored to specific AD subtypes.

Differences between pediatric and adult atopic dermatitis

Atopic dermatitis (AD) is a common disease with a broad spectrum of clinical manifestations. AD can manifest differently in adults than children. Core AD features are similar between children and adults overall, including lesions affecting flexural areas, presence of atopy, and xerosis. Adults have more signs of chronic disease, higher prevalence and different patterns of hand eczema, and a stronger relationship of disease activity with emotional factors, whereas children with AD have more exudative lesions, perifollicular accentuation, pityriasis alba, Dennie-Morgan folds, and seborrheic dermatitis-like presentation. These differences may be due in part to pathophysiologic differences in AD in children compared with adults. Atopic diseases commonly co-occur with AD, although most do not temporally have the "atopic march." Further research is warranted to better understand the differential roles of immune dysregulation, epidermal-barrier disruption, and dysbiosis between children and adults and determine whether such differences translate into differences in therapeutic efficacy.

Art of prevention: Atopic dermatitis in women and families of color-prevalence, recognition, and prevention

Atopic dermatitis (AD) is one of the most common skin conditions encountered by dermatologists. Skin of color (SOC) patients, in particular, are 50% more likely to visit a dermatologist for AD than non-SOC patients. While the misdiagnosis of AD in SOC patients is rare, the misinterpretation of severity or undertreatment of disease experienced by this patient population is a common occurrence. Herein, we present this Art of Prevention piece focused on the epidemiology, presentation, treatment, and management of AD in skin of color patients.

Multiple Roles for Cytokines in Atopic Dermatitis: From Pathogenic Mediators to Endotype-Specific Biomarkers to Therapeutic Targets

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, which generally presents with intense itching and recurrent eczematous lesions. AD affects up to 20% of children and 10% of adults in high-income countries. The prevalence and incidence of AD have increased in recent years. The onset of AD mostly occurs in childhood, although in some cases AD may persist in adult life or even manifest in middle age (adult-onset AD). AD pathophysiology is made of a complex net, in which genetic background, skin barrier dysfunction, innate and adaptive immune responses, as well as itch contribute to disease development, progression, and chronicization. One of the most important features of AD is skin dehydration, which is mainly caused by filaggrin mutations that determine trans-epidermal water loss, pH alterations, and antigen penetration. In accordance with the “outside-inside” theory of AD pathogenesis, in a context of an altered epidermal barrier, antigens encounter epidermal antigen presentation cells (APCs), such as epidermal Langerhans cells and inflammatory epidermal dendritic cells, leading to their maturation and Th-2 cell-mediated inflammation. APCs also bear trimeric high-affinity receptors for immunoglobulin E (IgE), which induce IgE-mediated sensitizations as part of pathogenic mechanisms leading to AD. In this review, we discuss the role of cytokines in the pathogenesis of AD, considering patients with various clinical AD phenotypes. Moreover, we describe the cytokine patterns in patients with AD at different phases of the disease evolution, as well as in relation to different phenotypes/endotypes, including age, race, and intrinsic/extrinsic subtypes. We also discuss the outcomes of current biologics for AD, which corroborate the presence of multiple cytokine axes involved in the background of AD. A deep insight into the correlation between cytokine patterns and the related clinical forms of AD is a crucial step towards increasingly personalized, and therefore more efficient therapy.

Early intervention and prevention of allergic diseases

Food allergy (FA) is now one of the most common chronic diseases of childhood often lasting throughout life and leading to significant worldwide healthcare burden. The precise mechanisms responsible for the development of this inflammatory condition are largely unknown; however, a multifactorial aetiology involving both environmental and genetic contributions is well accepted. A precise understanding of the pathogenesis of FA is an essential first step to developing comprehensive prevention strategies that could mitigate this epidemic. As it is frequently preceded by atopic dermatitis and can be prevented by early antigen introduction, the development of FA is likely facilitated by the improper initial presentation of antigen to the developing immune system. Primary oral exposure of antigens allowing for presentation via a well-developed mucosal immune system, rather than through a disrupted skin epidermal barrier, is essential to prevent FA. In this review, we present the data supporting the necessity of (1) an intact epidermal barrier to prevent epicutaneous antigen presentation, (2) the presence of specific commensal bacteria to maintain an intact mucosal immune system and (3) maternal/infant diet diversity, including vitamins and minerals, and appropriately timed allergenic food introduction to prevent FA.

Subtypes of atopic dermatitis: From phenotype to endotype

Atopic dermatitis (AD) is a heterogenous disorder and can be classified into different types. Stratification of subtypes may enable personalized medicine approaches. AD can be categorized into the IgE-high, extrinsic subtype and the IgE-normal, intrinsic subtype. While extrinsic AD is the major subtype possessing skin barrier impairment (high incidence of filaggrin mutations), intrinsic AD occupies about 20% of AD with female dominance and preserved barrier. Extrinsic AD exhibits protein allergy and food allergy, but intrinsic AD shows metal allergy possibly in association with suprabasin deficiency. In particular, accumulated knowledge of food allergy has more clearly characterized extrinsic AD. European American (EA) and Asian AD subtypes have been also proposed. Asian patients with AD are characterized by a unique blended immune dysregulation and barrier feature phenotype between EA patients with AD and those with psoriasis. In another ethnic study, filaggrin loss-of-function mutations are not prevalent in African American patients with AD, and Th1/Th17 attenuation and Th2/Th22 skewing were seen in these patients. Recent endotype classification provides new insights for AD and other allergic disorders. Endotype is defined as the molecular mechanisms underlying the visible features/phenotype. Endotype repertoire harbors activation of type 2 cytokines, type 1 cytokines, and IL-17/IL-22, impairment of epidermal barrier, and abnormalities of intercellular lipids. Classification of endotype has been attempted with serum markers. These lines of evidence indicate a need for personalized or precision medicine appropriate for each subtype of AD.