The impact of airborne pollution on atopic dermatitis: a literature review.

The increasing prevalence of atopic dermatitis (AD) parallels a global rise in industrialization and urban living over recent decades. This shift in lifestyle is accompanied by greater cutaneous exposure to environmental pollutants during the course of daily activities. The objectives of this review are to highlight the effects of airborne pollution on epidermal barrier function, examine evidence on the relationship between pollutants and AD, synthesize a proposed mechanism for pollution-induced exacerbation of AD, and identify potential methods for the reduction and prevention of pollutant-induced skin damage. The literature review was done by searching the PubMed, Embase and Google Scholar databases. Inclusion criteria were in vitro and animal studies, clinical trials and case series. Non-English-language publications, review articles and case reports were excluded. Pollutants induce cutaneous oxidative stress and have been shown to damage skin barrier integrity by altering transepidermal water loss, inflammatory signalling, stratum corneum pH and the skin microbiome. AD represents a state of inherent barrier dysfunction, and both long- and short-term pollutant exposure have been linked to exacerbation of AD symptoms and increased AD rates in population studies. Airborne pollutants have a detrimental effect on skin barrier integrity and AD symptoms, and appear to pose a multifaceted threat in AD through several parallel mechanisms, including oxidative damage, barrier dysfunction, immune stimulation and propagation of the itch-scratch cycle. Future research is needed to elucidate specific mechanisms of pollution-induced epidermal barrier dysfunction and to identify efficacious methods of skin barrier repair and protection against pollutant-driven damage.

Recent advances in hidradenitis suppurativa in pediatrics.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that can cause significant physical, mental, and socioeconomic burden. There remains a paucity of literature on HS in the pediatric population. This systematic review highlights recent advances in pediatric HS in epidemiology, presentation, comorbidities, and management. PubMed, Embase, Google Scholar, and Clinicaltrials.gov databases were used to identify trials and articles published on HS in pediatric patients between January 2015 and October 2019. A total of 39 articles were included. Current evidence suggests that pediatric onset HS may be associated with genetic factors along with endocrine and metabolic abnormalities. Delayed diagnosis in children with HS contributes to poor outcomes. Overall, children and adults with HS share similar lesion types and involved areas. Pediatric HS is associated with a number of comorbid conditions including acne, obesity, inflammatory joint disease, Down syndrome, inflammatory bowel disease, and diabetes. There are currently no pediatric treatment guidelines. Adalimumab is approved for the treatment of moderate-to-severe HS in children 12 and older. Other targeted immunomodulators and hormonal modulators are under investigation. Although the number of studies concerning HS are increasing, further investigation is warranted to better characterize HS, facilitate early diagnosis, and determine the best management for children.

In Vivo Reflectance Confocal Microscopy: Emerging Role in Noninvasive Diagnosis and Monitoring of Eczematous Dermatoses. / Microscopia confocal de reflectancia in vivo: papel emergente en el diagnóstico no invasivo, así como en el seguimiento de las dermatosis eccematosas.

Dermatologic diagnosis and monitoring have been dependent largely on visual grading. A skin biopsy is performed in case of diagnostic uncertainty, but can be traumatic, and results are delayed due to time for specimen transport and processing. Biopsies also destroy specimens, prohibiting lesion evolution monitoring. In vivo reflectance confocal microscopy (RCM) offers a diagnostic alternative to skin biopsy. RCM captures real-time, high-resolution images, and has been piloted for the evaluation of various dermatologic conditions. Identification of unique RCM features may distinguish dermatoses with similar clinical morphologies. Allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) are diagnosed by patch testing that currently uses a subjective scoring system. RCM has increasingly been studied for early detection and severity grading of CD. Common RCM features shared by ACD and ICD are stratum corneum disruption, vesicle formation, exocytosis, spongiosis, and parakeratosis. Features unique to ACD are vasodilation, increased epidermal thickness, intercellular edema, and acanthosis. Features unique to ICD are detached corneocytes and targetoid keratinocytes. This review summarizes the use of RCM in evaluating contact eccematous conditions and aims to spark future research and interest in this promising tool.

The impact of stress on epidermal barrier function: an evidence-based review.

BACKGROUND: The epidermal barrier functions to limit skin infection and inflammation by inhibiting irritant and immunogen invasion. Abundant evidence suggests that psychological stress stemming from crowding, isolation, nicotine smoking, insomnia, mental arithmetic tasks, physical pain, real-life stressors (examinations and marital strain) and lack of positive personality traits may impart both acute and chronic epidermal dysfunction. OBJECTIVES: To review the relationship between stress and epidermal barrier dysfunction. METHODS: A review of the PubMed and Embase databases was conducted to identify all English-language case-control, cross-sectional and randomized control trials that have reported the effect of stress on epidermal barrier function. The authors' conclusions are based on the available evidence from 21 studies that met the inclusion and exclusion criteria. RESULTS: Psychological stressors upregulate the hypothalamic-pituitary-adrenal axis to stimulate local and systemic stress hormone production. This ultimately leads to aberrant barrier dysfunction, characterized by decreased epidermal lipid and structural protein production, decreased stratum corneum hydration and increased transepidermal water loss. CONCLUSIONS: This evidence-based review explores the adverse effects of psychological stressors on epidermal barrier function. Future investigations using more real-life stressors are needed to elucidate further their impact on skin physiology and identify practical stress-relieving therapies that minimize and restore epidermal barrier dysfunction, particularly in at-risk populations. What's already known about this topic? The literature reports the negative effect of stress on prolonged wound healing. Less is known about the relationship between stress and epidermal barrier dysfunction, a chronic, superficial wound involving the upper epidermal layers. What does this study add? Psychological stressors impact epidermal barrier function by activating the hypothalamic-pituitary-adrenal axis to stimulate local and systemic stress hormone production. Stress hormones negatively affect the epidermal barrier by decreasing epidermal lipids and structural proteins, decreasing stratum corneum hydration and increasing transepidermal water loss. Identification of such stressors can promote stress-avoidance and stress-reduction behaviours that protect epidermal barrier function and prevent certain dermatological conditions.

Topical micronutrients in atopic dermatitis-An evidence-based review.

The role of dietary factors is an important and controversial topic in the pathogenesis of atopic dermatitis (AD). Despite the preponderance of consumer products utilizing oral micronutrients supplementation for relief AD symptoms, less attention has been paid on the utility of topical micronutrients, specifically for individuals with AD. We review evidence on topical formulations of vitamins (A, B, C, D, and E) and trace minerals (magnesium, manganese, zinc, and iodine) for treatment of AD. While topical B, C, and E formulations appear to provide some benefit to AD individuals, topical vitamin A has no utility, and topical vitamin D may exacerbate symptoms. Magnesium, zinc, and iodine all appear to improve AD through anti-inflammatory and anti-microbial effects, though future studies must evaluate their use as monotherapy. The exposition of the effects that topical micronutrients have on AD offers an adjuvant treatment modality for this common inflammatory dermatosis.

Epithelial barrier dysfunctions in atopic dermatitis: a skin-gut-lung model linking microbiome alteration and immune dysregulation.

BACKGROUND: Atopic dermatitis is a systemic disorder characterized by abnormal barrier function across multiple organ sites. Causes of epidermal barrier breakdown are complex and driven by a combination of structural, genetic, environmental and immunological factors. In addition, alteration in microflora diversity can influence disease severity, duration, and response to treatment. Clinically, atopic dermatitis can progress from skin disease to food allergy, allergic rhinitis, and later asthma, a phenomenon commonly known as the atopic march. The mechanism by which atopic dermatitis progresses towards gastrointestinal or airway disease remains to be elucidated. OBJECTIVES: This review addresses how epithelial dysfunction linking microbiome alteration and immune dysregulation can predispose to the development of the atopic march. METHODS: A literature search was conducted using the PubMed database for relevant articles with the keywords 'atopic dermatitis', 'epithelial barrier', 'skin', 'gut', 'lung', 'microbiome' and 'immune dysregulation'. RESULTS: Initial disruption in the skin epidermal barrier permits allergen sensitization and colonization by pathogens. This induces a T helper 2 inflammatory response and a thymic stromal lymphopoietin-mediated pathway that further promotes barrier breakdown at distant sites, including the intestinal and respiratory tract. CONCLUSIONS: As there are no immediate cures for food allergy or asthma, early intervention aimed at protecting the skin barrier and effective control of local and systemic inflammation may improve long-term outcomes and reduce allergen sensitization in the airway and gut.