About allergies

Approximately 30% of the world population is affected by one or more allergic conditions1, and it is expected that by 2050, several billion people will suffer from allergies.

The increasing prevalence and intensity of allergies is a trend that has continued in the industrialised world for more than 60 years. 

Allergy is a disorder of the immune system which reacts to a normally harmless foreign substance such as house dust mites, pollens, or certain foods. In people with allergies, the immune system produces antibodies that identify a particular allergen as harmful following contact, ingestion or even inhalation. The immune system’s reaction can cause inflammation of the skin, sinuses, respiratory airways, or digestive system. 

Allergic reactions are a common, chronic, often debilitating and sometimes even fatal condition. The consequences on health vary from decreases in lung function, new onset of diseases, exacerbation of chronic respiratory diseases, and may lead to anaphylaxis. 



1. Sánchez-Borges, M, et al. (2018). The importance of allergic disease in public health: an iCAALL statement. World Allergy Organization Journal 11(1):1-3  
2. Lotvall, et al (2012). “We call for iCAALL: International Collaboration in Asthma, Allergy and Immunology.” The Journal of allergy and clinical immunology 129(4): 904-905. 

Pollution and climate change >

The number of people affected by respiratory allergies and asthma has been increasing steadily for decades, in both industrialised and nonindustrialised countries, due to changes in our environment. The quality of the air we breathe has become an important concern for public health authorities around the world.

Motor vehicle emissions and increased urbanisation are linked to the rising prevalence of pollen-induced respiratory allergies. Observational evidence indicates that recent regional changes in climate, particularly temperature increases, have already affected a diverse set of physical and biological systems in many parts of the world. Climate change is also affecting allergen patterns and air pollution can modify the allergenic potential of pollens especially in presence of specific weather conditions.

The consequences on health vary from decreases in lung function to allergic diseases, new onset of diseases, and exacerbation of chronic respiratory diseases1


1. D’Amato G, Liccardi G, D’Amato M. The role of outdoor air pollution and climatic changes on the rising trends in respiratory allergy. Repir Med. 2001 Jul;95(7):606-11.

Last updated on: 16/04/2020

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