Exposure to road traffic enhances allergic skin wheal responses and increases plasma neuropeptides and neurotrophins in patients with atopic eczema/dermatitis syndrome

Comparison of Pollutant Effects on Cutaneous Inflammasomes Activation

The skin is the outermost layer of the body and, therefore, is exposed to a variety of stressors, such as environmental pollutants, known to cause oxinflammatory reactions involved in the exacerbation of several skin conditions. Today, inflammasomes are recognized as important modulators of the cutaneous inflammatory status in response to air pollutants and ultraviolet (UV) light exposure. In this study, human skin explants were exposed to the best-recognized air pollutants, such as microplastics (MP), cigarette smoke (CS), diesel engine exhaust (DEE), ozone (O3), and UV, for 1 or 4 days, to explore how each pollutant can differently modulate markers of cutaneous oxinflammation. Exposure to environmental pollutants caused an altered oxidative stress response, accompanied by increased DNA damage and signs of premature skin aging. The effect of specific pollutants being able to exert different inflammasomes pathways (NLRP1, NLRP3, NLRP6, and NLRC4) was also investigated in terms of scaffold formation and cell pyroptosis. Among all environmental pollutants, O3, MP, and UV represented the main pollutants affecting cutaneous redox homeostasis; of note, the NLRP1 and NLRP6 inflammasomes were the main ones modulated by these outdoor stressors, suggesting their role as possible molecular targets in preventing skin disorders and the inflammaging events associated with environmental pollutant exposure.

Exposure to air pollution and incidence of atopic dermatitis in the general population: A national population-based retrospective cohort study

BACKGROUND

To date, little evidence is available to determine whether atopic dermatitis (AD) can be caused by exposure to air pollutants, including gases and particulate matter.

OBJECTIVE

We aimed to evaluate the relationship between air pollutants and incidence of AD using the National Health Insurance Service-National Sample Cohort database.

METHODS

We included 209,168 subjects from the general population previously not diagnosed with AD between 2008 and 2013. Long-term average concentration of air pollutants before diagnosis was calculated for each subject.

RESULTS

For 1,030,324 person-years, incident cases of AD were observed in 3203 subjects. There was a significant positive association between incidence of AD and long-term average concentration of particulate matter smaller than 2.5 μm in diameter (hazard ratio [HR], 1.420; 95% CI, 1.392-1.448; for 1 μg/m³), particulate matter smaller than 10 μm in diameter (HR, 1.333, 95% CI, 1.325-1.341; for 1 μg/m³), sulfur dioxide (HR, 1.626; 95% CI, 1.559-1.695; for 1 parts per billion), nitrogen dioxide (HR, 1.200; 95% CI, 1.187-1.212; for 1 parts per billion), and carbon monoxide (HR, 1.005; 95% CI, 1.004-1.005; for 1 parts per billion) after adjusting for age, sex, income, comorbid diseases, and meteorologic variables.

LIMITATIONS

The National Health Insurance Service database lacks detailed information on individual subjects.

CONCLUSIONS

This study demonstrated that long-term exposure to air pollutants, including gases and particulate matter, is an independent risk factor for developing AD.

Association between particulate matter concentration and symptoms of atopic dermatitis in children living in an industrial urban area of South Korea

INTRODUCTION

Increased exposure to particulate matter (PM) appears to increase the development of atopic diseases and allergic sensitization. This study evaluated the association between daily levels of PM with diameters less than 10µm (PM10) and PM2.5 and symptoms of atopic dermatitis (AD) in children living in an industrial urban area.

METHODS

Indoor PM10 and PM2.5 concentrations were measured with an optical particle counter in two preschools near large industrial complexes in Ulsan, South Korea during two 6-month periods (May-October of 2012 and 2013). Twenty-one children with AD from these preschools were enrolled and observed daily for AD symptoms during the same periods. Indoor and outdoor PM concentrations were used to estimate PM exposure based on time activity patterns.

RESULTS

Analysis of PM10 and PM2.5 concentrations showed that indoor and outdoor PM10 levels varied similarly throughout each 6-month period. In addition, indoor concentration of PM2.5 had high correlation with ambient outdoor concentration of PM10. Correlation analysis also indicated a significant positive correlation between the exacerbation of AD symptoms and daily mean exposure to PM10 and PM2.5. Based on a generalized linear mixed model (GLMM), PM exposure was significantly associated with the exacerbation of AD symptoms, with a maximum adjusted odds ratio (aOR) of 1.399 for a 10µg/m³ increase of PM2.5 (95% CI: 1.216-1.610).

DISCUSSION

Our findings suggest that short-term exposure to PM can exacerbate AD in young children living in an industrial urban area. PM2.5 had a stronger effect than PM10 on exacerbation of AD symptoms.

Acute health effects of urban fine and ultrafine particles on children with atopic dermatitis

Although ambient particulate pollutants have been shown to exacerbate existing allergic symptoms of mucous membranes including rhinitis and asthma, the effects on skin such as atopic dermatitis in childhood deserve further study. We investigated the effects of urban particulate pollutants including ultrafine particles on atopic severity in children with atopic dermatitis. We included 41 schoolchildren, 8-12 years old, who had been diagnosed with atopic dermatitis. For 67 consecutive days, all of them measured their symptoms in a diary. To assess exposure, the daily ambient mass concentrations of particulate matter less than 10, 2.5 and 1 μm (PM(10), PM(2.5) and PM(1), respectively) and concentrations of submicron particles (0.01- 1 μm) were measured at a local school. The mean mass concentrations of PM(10), PM(2.5) and PM(1) were 74.0, 57.8 and 50.8 μg/m(3), respectively. The mean concentrations were 41,335/cm(3) ultrafine particles (UFPs) and 8577/cm(3) accumulation mode (0.1-1 μm) particles. Significant associations were found between the concentrations of ultrafine particles and the itchiness symptom in children with atopic dermatitis. An interquartile range (IQR) increase in previous day ultrafine particles concentration (IQR: 28-140/m(3)) was significantly associated with a 3.1% (95% confidence interval, 0.2-6.1) increase in the itch symptom score for children with atopic dermatitis. The results suggested that the concentration of ambient ultrafine particles may exacerbate skin symptoms in children with atopic dermatitis.

Sensitivity-related illness: the escalating pandemic of allergy, food intolerance and chemical sensitivity

The prevalence of allergic-related diseases, food intolerance, and chemical sensitivities in both the pediatric and adult population has increased dramatically over the last two decades, with escalating rates of associated morbidity. Conditions of acquired allergy, food intolerance and chemical hypersensitivity are frequently the direct sequelae of a toxicant induced loss of tolerance (TILT) in response to a significant initiating toxic exposure. Following the primary toxicant insult, the individuals become sensitive to low levels of diverse and unrelated triggers in their environment such as commonly encountered chemical, inhalant or food antigens. Among sensitized individuals, exposure to assorted inciting stimuli may precipitate diverse clinical and/or immune sequelae as may be evidenced by clinical symptoms as well as varied lymphocyte, antibody, or cytokine responses in some cases. Recently recognized as a mechanism of disease development, TILT and resultant sensitivity-related illness (SRI) may involve various organ systems and evoke wide-ranging physical or neuropsychological manifestations. With escalating rates of toxicant exposure and bioaccumulation in the population-at-large, an increasing proportion of contemporary illness is the direct result of TILT and ensuing SRI. Avoidance of triggers will preclude symptoms, and desensitization immunotherapy or immune suppression may ameliorate symptomatology in some cases. Resolution of SRI generally occurs on a gradual basis following the elimination of bioaccumulated toxicity and avoidance of further initiating adverse environmental exposures. As has usually been the case throughout medical history whenever new evidence regarding disease mechanisms emerges, resistance to the translation of knowledge abounds.

Traffic exposure associated with allergic asthma and allergic rhinitis in adults. A cross-sectional study in southern Sweden

Background

There is conflicting evidence that traffic-related air pollution is a risk factor for allergic conditions. Few studies have investigated this in adults. In adults, a high proportion of asthma, rhinitis and eczema is triggered by non-allergic factors. We investigated traffic as a risk factor for allergic versus non-allergic asthma and rhinitis, and eczema, in adults.

A questionnaire from 2000 (n = 9319, 18–77 years) provided individual data about disease outcome and self-reported traffic exposure. Additional exposure assessments were obtained using Geographical Informations Systems (GIS). Residential addresses were linked to the national Swedish Road Database and to a pollutant database with modelled annual means of NO_x (Nitrogen Oxids).

Results

Living within 100 m from a road with a traffic intensity of >10 cars/min (24 hour mean) was associated with prevalence of current asthma reported to be triggered by allergic factors (OR = 1.83, 95% CI = 1.23–2.72) and with allergic rhinitis (OR = 1.30, 95%CI = (1.05–1.61). No relation was seen with asthma or rhinitis triggered by other factors. Living within 100 m of a road with >10 cars/min was also associated with hand-eczema during the last 12 months (OR = 1.63, 95% CI = 1.19–2.23), but not with allergic eczema or diagnosed hand-eczema. Consistent results were seen using self-reported traffic, but the associations with NO_x were less consistent.

Conclusion

Exposure to traffic was associated with a higher prevalence of allergic asthma and allergic rhinitis, but not with asthma or rhinitis triggered by non-allergic factors. This difference was suggested by the overall pattern, but only clear using GIS-measured traffic intensity as a proxy for traffic exposure. An association was also found with hand-eczema during the last 12 months. We suggest that asthma and rhinitis should not be treated as homogenous groups when estimating effects from traffic in adults.

Inhibition of pan neurotrophin receptor p75 attenuates diesel particulate-induced enhancement of allergic airway responses in C57/B16J mice

Recent investigations have linked neurotrophins, including nerve growth factor (NGF), neurotrophin-3 (NT-3), and brain-derived neurotrophic factor (BDNF), to allergic airways diseases. Antibody blockade of NGF attenuates airway resistance in allergic mice. Diesel exhaust particle (DEP) exposure has been linked to asthma exacerbation in many cities with vehicular traffic congestion. We tested the hypothesis that DEP-induced enhancement of the hallmark features of allergic airway disease in a murine model is dependent on the function of the pan neurotrophin receptor p75. Ovalbumin (OVA)-sensitized C57B1/6J mice were intranasally instilled with an antibody against the p75 receptor or saline alone 1 h before OVA challenge. The mice were then exposed nose-only to the PM2.5 fraction of SRM2975 DEP or air alone for 5 h beginning 1 h after OVA challenge. Two days later, air-exposed OVA-allergic mice developed a small but insignificant increase in methacholine-induced airflow obstruction relative to air-exposed, vehicle-sensitized mice. DEP-exposed OVA-allergic mice had a significantly greater degree of airway obstruction than all other groups. Instillation of anti-p75 significantly attenuated the DEP-induced increase in airway obstruction in OVA-allergic mice to levels similar to non-sensitized mice. The DEP-induced exacerbation of allergic airway responses may, in part, be mediated by neurotrophins.

What causes worsening of eczema? A systematic review

BACKGROUND

Flares of eczema are attributed to many factors, often with minimal scientific evidence.

OBJECTIVES

Systematically to search, summarize and critically appraise the scientific evidence to support the roles of individual 'flare factors' in eczema.

METHODS

We searched Medline from 1966 until 20 April 2005 to identify relevant articles for inclusion in this review. No language restrictions were imposed. All study designs were included and were ranked according to the strength of evidence. Experimental and provocation studies were restricted to those using a double-blind design. We included randomized controlled trials if they were provocation studies. Meta-analysis was not possible due to differences in study populations and methodology. The studies are therefore described qualitatively.

RESULTS

The roles of foodstuffs (13 studies), house dust mite (three), other aeroallergens (two), seasonality (two), bacterial infections (one), textiles (three), detergents (one), sunlight (one) and stress (two) were assessed in different study populations, using a variety of study designs. All studies were performed on selected groups and only four were longitudinal in design. Collectively, these studies provide some evidence that certain foods, house dust mite, stress and seasonal factors are relevant causes of disease worsening in certain subgroups with eczema. No good evidence could be found to support the role of detergents, textiles and irritants in causing worsening of eczema.

CONCLUSIONS

Despite anecdotal lists in textbooks and review articles, very little good evidence exists for 'flare factors' in eczema. The focus of all of the included studies was on disease worsening rather than clinically relevant flares. Studies of longitudinal design are required to clarify the roles of these and other putative flare factors in eczema.