Role of genetic aspect in pathogenesis of atopic dermatitis

The pathogenesis of atopic dermatitis (AD) is a very complicated process that involves an intricate array of molecules. Nowadays it is generally accepted that cytokines play an important role in the progression of the clinical presentation of atopic dermatitis. However, emerging data point to the possible involvement of cornified envelope proteins in the development of skin barrier dysfunction and illness. Unfortunately, our knowledge on relation of particular genotype to progression of AD is very limited. Therefore, intensive studies are needed to increase our understanding of genetic background of atopic dermatitis. Hopefully the future research will identify new factors that help us to determine the additional risk for certain patients with atopic dermatitis

The course of life of patients with childhood atopic dermatitis

Atopic dermatitis mainly covers the period of infancy to adulthood, an important period in the development of an individual. The impairment of quality of life and the psychological wellbeing of children with atopic dermatitis have been well documented but so far no data exist about the impact of atopic dermatitis in childhood on fulfilling age-specific developmental tasks and achieving developmental milestones during this period, referred to as the course of life. The aims of this study were to: (i) assess the course of life and define the disease-related consequences in young adult patients with childhood atopic dermatitis and (ii) determine whether the severity of atopic dermatitis is predictive for the course of life, the disease-related consequences and quality of life later in life. Adult patients who grew up with atopic dermatitis were asked to complete a medical history questionnaire, the Skindex-29, the "course of life" questionnaire and a subjective disease-specific questionnaire. Patients with severe atopic dermatitis in childhood showed a significant delayed social development in their course of life. The results of the disease-specific questionnaire demonstrated remarkable high percentages of psycho-social consequences and physical discomfort caused by atopic dermatitis in childhood. Patients showed a severely negative impact of atopic dermatitis on their current quality of life. This is the first study that applied the "course of life" questionnaire in atopic dermatitis. More insight in the course of life, disease-specific consequences and quality of life of atopic dermatitis is of high importance, especially in case of severe atopic dermatitis. © 2009 The Authors

Consensus on the Clinical Approach to Moderate-to-Severe Atopic Dermatitis in Spain: A Delphi Survey

Background. The purpose of this study was to gather information on the current assessment and management of patients with moderate-to-severe AD in routine daily practice. Methods. A cross-sectional two-round Delphi survey with the participation of dermatologists and allergologists throughout Spain was conducted. They completed a 46-item questionnaire, and consensus was defined when responses of >= 80% of participants coincided in the categories of a 5-point Likert scale for that item. Results. A total of 105 specialists (aged 40-59 years) completed the two rounds. Participants agreed regarding the consideration of AD as a multifaceted disease and the differences in clinical presentation of AD according to the patient's age. It is recommendable to perform a skin biopsy to exclude early stage T-cell cutaneous lymphoma, psoriasis, or dermatitis herpetiformis, among others (99.1%). Also, consensus was reached regarding the use of the SCORAD index to quantify the severity of the disease (86.7%), the use of wet wraps to increase the effect of topical corticosteroids (90.4%), the usefulness of proactive treatment during follow-up (85.6%) and tacrolimus ointment (91.2%) to reduce new flares, and the fact that crisaborole is not the treatment of choice for severe AD (92.4%). AD was not considered a contraindication for immunotherapy in patients with allergic respiratory diseases (92.4%). In patients with severe AD, the use of immune response modifier drugs (97.6%) or phototherapy (92.8%) does not sufficiently cover their treatment needs. Consensus was also obtained regarding the role of the new biologic drugs (93.6%) targeting cytokines involved in the Th2 inflammatory pathway (92.0%) and the potential role of dupilumab as first-line treatment (90.4%) in moderate-to-severe AD patients. Conclusion. This study contributes a reference framework to the care of AD patients. There is no diagnostic test or biomarkers to direct treatment or to assess the severity of the disease, and many therapeutic challenges remain

Neutrophils promote CXCR3-dependent itch in the development of atopic dermatitis.

Chronic itch remains a highly prevalent disorder with limited treatment options. Most chronic itch diseases are thought to be driven by both the nervous and immune systems, but the fundamental molecular and cellular interactions that trigger the development of itch and the acute-to-chronic itch transition remain unknown. Here, we show that skin-infiltrating neutrophils are key initiators of itch in atopic dermatitis, the most prevalent chronic itch disorder. Neutrophil depletion significantly attenuated itch-evoked scratching in a mouse model of atopic dermatitis. Neutrophils were also required for several key hallmarks of chronic itch, including skin hyperinnervation, enhanced expression of itch signaling molecules, and upregulation of inflammatory cytokines, activity-induced genes, and markers of neuropathic itch. Finally, we demonstrate that neutrophils are required for induction of CXCL10, a ligand of the CXCR3 receptor that promotes itch via activation of sensory neurons, and we find that that CXCR3 antagonism attenuates chronic itch

Inflammatory cytokines and biofilm production sustain Staphylococcus aureus outgrowth and persistence: A pivotal interplay in the pathogenesis of Atopic Dermatitis

Individuals with Atopic dermatitis (AD) are highly susceptible to Staphylococcus aureus colonization. However, the mechanisms driving this process as well as the impact of S. aureus in AD pathogenesis are still incompletely understood. In this study, we analysed the role of biofilm in sustaining S. aureus chronic persistence and its impact on AD severity. Further we explored whether key inflammatory cytokines overexpressed in AD might provide a selective advantage to S. aureus. Results show that the strength of biofilm production by S. aureus correlated with the severity of the skin lesion, being significantly higher (P < 0.01) in patients with a more severe form of the disease as compared to those individuals with mild AD. Additionally, interleukin (IL)-β and interferon γ (IFN-γ), but not interleukin (IL)-6, induced a concentration-dependent increase of S. aureus growth. This effect was not observed with coagulase-negative staphylococci isolated from the skin of AD patients. These findings indicate that inflammatory cytokines such as IL1-β and IFN-γ, can selectively promote S. aureus outgrowth, thus subverting the composition of the healthy skin microbiome. Moreover, biofilm production by S. aureus plays a relevant role in further supporting chronic colonization and disease severity, while providing an increased tolerance to antimicrobials

Pollen grains induce a rapid and biphasic eczematous immune response in atopic eczema patients

Introduction: Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. Yet, the underlying immunological mechanisms are not well understood. Material and Methods: To delineate the effect of native pollen grains on human skin of healthy and atopic individuals we performed patch tests (atopy patch test with native pollen grains, PPT). Nickel patch tests (NPT) served as an established model of contact dermatitis. Skin site biopsies were taken 6 - 96 h after allergen application and investigated immunohistochemically. Results: Histology of positive patch tests showed an influx of mononuclear cells (predominantly CD4+, CD25+, CD45RO+). This influx was detected earlier in the PPT reaction than in the immune response to nickel. A biphasic cytokine response could be detected in the PPT: IL-5 dominated in the early, IFN-gamma in the late phase. The NPT was continuously dominated by IFN-gamma. Dendritic cell subpopulations imitated the earlier kinetics of the mononuclear infiltrate. Discussion: Thus, pollen grains induce eczematous reactions in susceptible individuals. This reaction appears clinically and immunohistochemically similar to the contact hypersensitivity reaction to nickel but follows a faster kinetic and a biphasic course: Th2 and IgE in the early (24 h) and Th1 predominance in the late (96 h) phase. Copyright (c) 2007 S. Karger AG, Basel

The microbiome in patients with atopic dermatitis.

As an interface with the environment, the skin is a complex ecosystem colonized by many microorganisms that coexist in an established balance. The cutaneous microbiome inhibits colonization with pathogens, such as Staphylococcus aureus, and is a crucial component for function of the epidermal barrier. Moreover, crosstalk between commensals and the immune system is now recognized because microorganisms can modulate both innate and adaptive immune responses. Host-commensal interactions also have an effect on the developing immune system in infants and, subsequently, the occurrence of diseases, such as asthma and atopic dermatitis (AD). Later in life, the cutaneous microbiome contributes to the development and course of skin disease. Accordingly, in patients with AD, a decrease in microbiome diversity correlates with disease severity and increased colonization with pathogenic bacteria, such as S aureus. Early clinical studies suggest that topical application of commensal organisms (eg, Staphylococcus hominis or Roseomonas mucosa) reduces AD severity, which supports an important role for commensals in decreasing S aureus colonization in patients with AD. Advancing knowledge of the cutaneous microbiome and its function in modulating the course of skin disorders, such as AD, might result in novel therapeutic strategies