Thunderstorm Asthma: In Search For Relationships With Airborne Pollen And Fungal Spores From 23 Sites In Bavaria, Germany. A Rare Incident Or A Common Threat?

Global warming and implications for epithelial barrier disruption and respiratory and dermatologic allergic diseases

Global warming has direct and indirect effects, as well as short- and long-term impacts on the respiratory and skin barriers. Extreme temperature directly affects the airway epithelial barrier by disrupting the structural proteins and by triggering airway inflammation and hyperreactivity. It enhances tidal volume and respiratory rate by affecting the thermoregulatory system, causing specific airway resistance and reflex bronchoconstriction via activation of bronchopulmonary vagal C fibers and upregulation of transient receptor potential vanilloid (TRPV) 1 and TRPV4. Heat shock proteins are activated under heat stress and contribute to both epithelial barrier dysfunction and airway inflammation. Accordingly, the frequency and severity of allergic rhinitis and asthma have been increasing. Heat activates TRPV3 in keratinocytes, causing the secretion of inflammatory mediators and eventually pruritus. Exposure to air pollutants alters the expression of genes that control skin barrier integrity and triggers an immune response, increasing the incidence and prevalence of atopic dermatitis. There is evidence that extreme temperature, heavy rains and floods, air pollution, and wildfires increase atopic dermatitis flares. In this narrative review, focused on the last 3 years of literature, we explore the effects of global warming on respiratory and skin barrier and their clinical consequences.

Climate change and allergies

The climate crisis poses a major challenge to human health as well as the healthcare system and threatens to jeopardize the medical progress made in recent decades. However, addressing climate change may also be the greatest opportunity for global health in the 21st century. The climate crisis and its consequences, such as rising temperatures, forest fires, floods, droughts, and changes in the quality and quantity of food and water, directly and indirectly affect human physical and mental health. More intense and frequent heat waves and declining air quality have been shown to increase all-cause mortality, especially among the most vulnerable. Climate warming alters existing ecosystems and favors biological invasions by species that better tolerate heat and drought. Pathogen profiles are changing, and the transmission and spread of vector-borne diseases are increasing. The spread of neophytes in Europe, such as ragweed, is creating new pollen sources that increase allergen exposure for allergy sufferers. In addition, the overall milder weather, especially in combination with air pollution and increased CO₂ levels, is changing the production and allergenicity of pollen. The phenomenon of thunderstorm asthma is also occurring more frequently. In view of the increasing prevalence of allergic diseases due to climate change, early causal immunomodulatory therapy is therefore all the more important. During a climate consultation, patients can receive individual advice on climate adaptation and resilience and the benefits of CO₂ reduction-for their own and the planet's health. Almost 5% of all greenhouse gas emissions in Europe come from the healthcare sector. It thus has a central responsibility for a climate-neutral and sustainable transformation.

Klimawandel und Allergien

Die Klimakrise stellt eine große Herausforderung für die menschliche Gesundheit sowie das Gesundheitssystem dar und droht, den medizinischen Fortschritt der letzten Jahrzehnte zu gefährden. In der Bewältigung des Klimawandels könnte jedoch auch die größte Chance für die globale Gesundheit im 21. Jahrhundert liegen.

Die Klimakrise und ihre Folgen, wie steigende Temperaturen, Waldbrände, Überschwemmungen, Dürren, Veränderungen in der Qualität und Quantität von Nahrungsmitteln und des Wassers wirken sich direkt und indirekt auf die physische und psychische Gesundheit des Menschen aus. Intensivere und häufigere Hitzewellen und die abnehmende Luftqualität erhöhen nachweislich die Gesamtmortalität, insbesondere bei den am meisten vulnerablen Personen. Die Klimaerwärmung verändert die bestehenden Ökosysteme und begünstigt biologische Invasionen von Arten, die Wärme und Trockenheit besser tolerieren. Die Erregerprofile verändern sich, die Übertragung und Verbreitung von durch Vektoren übertragene Krankheiten nehmen zu. Durch die Ausbreitung von Neophyten in Europa, wie beispielsweise der Ambrosiapflanze, entstehen neue Pollenquellen, die die Allergenexposition für Allergiker*innen erhöhen. Darüber hinaus verändert die insgesamt mildere Witterung, gerade in Kombination mit der Luftverschmutzung und einem erhöhten CO₂-Gehalt, die Produktion und Allergenität von Pollen. Das Phänomen Thunderstorm-Asthma tritt zudem häufiger auf. Angesichts der durch den Klimawandel zunehmenden Prävalenz von allergischen Erkrankungen ist eine frühzeitige kausale immunmodulierende Therapie umso wichtiger.

Im Rahmen einer Klimasprechstunde können Patient*innen individuell bezüglich einer Klimaadaption und -resilienz und der Vorteile einer CO₂-Reduzierung beraten werden - für die eigene und die planetare Gesundheit. Fast 5 % aller Treibhausgasemissionen in Europa stammen aus dem Gesundheitssektor. Er hat damit eine zentrale Verantwortung für eine klimaneutrale und nachhaltige Transformation.

Zitierweise: Luschkova D, Traidl-Hoffmann C, Ludwig A. Climate change and allergies. Allergo J Int 2022;31:114-20

https://doi.org/10.1007/s40629-022-00212-x

Epithelial barrier hypothesis: Effect of the external exposome on the microbiome and epithelial barriers in allergic disease

Environmental exposure plays a major role in the development of allergic diseases. The exposome can be classified into internal (e.g., aging, hormones, and metabolic processes), specific external (e.g., chemical pollutants or lifestyle factors), and general external (e.g., broader socioeconomic and psychological contexts) domains, all of which are interrelated. All the factors we are exposed to, from the moment of conception to death, are part of the external exposome. Several hundreds of thousands of new chemicals have been introduced in modern life without our having a full understanding of their toxic health effects and ways to mitigate these effects. Climate change, air pollution, microplastics, tobacco smoke, changes and loss of biodiversity, alterations in dietary habits, and the microbiome due to modernization, urbanization, and globalization constitute our surrounding environment and external exposome. Some of these factors disrupt the epithelial barriers of the skin and mucosal surfaces, and these disruptions have been linked in the last few decades to the increasing prevalence and severity of allergic and inflammatory diseases such as atopic dermatitis, food allergy, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis, and asthma. The epithelial barrier hypothesis provides a mechanistic explanation of how these factors can explain the rapid increase in allergic and autoimmune diseases. In this review, we discuss factors affecting the planet's health in the context of the 'epithelial barrier hypothesis,' including climate change, pollution, changes and loss of biodiversity, and emphasize the changes in the external exposome in the last few decades and their effects on allergic diseases. In addition, the roles of increased dietary fatty acid consumption and environmental substances (detergents, airborne pollen, ozone, microplastics, nanoparticles, and tobacco) affecting epithelial barriers are discussed. Considering the emerging data from recent studies, we suggest stringent governmental regulations, global policy adjustments, patient education, and the establishment of individualized control measures to mitigate environmental threats and decrease allergic disease.

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Die Klimakrise stellt eine große Herausforderung für die menschliche Gesundheit sowie das Gesundheitssystem dar und droht, den medizinischen Fortschritt der letzten Jahrzehnte zu gefährden. In der Bewältigung des Klimawandels könnte jedoch auch die größte Chance für die globale Gesundheit im 21. Jahrhundert liegen.