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March 5, 2014

Climate Change Effects on Allergy


I am an allergist in a small community and I have been invited to be part of a panel on a TV current events program to discuss the effects of climate change on allergy in the community. I am aware of some data on the earlier start and prolonged nature of seasonal pollens. Is there good evidence of other changes we can expect?


By Prof. Nelson Rosario

Climate changes may influence negatively seasonal allergies for several reasons: plants can grow faster and produce more pollen; the content of allergenic material is increased as well; Bud set and flowering are intimately linked to accumulated warmth for many herbaceous and woody plants. Anthropogenic global warming speeds flower development, resulting in earlier blooming. Pollen season starts earlier and may be longer than usual. Symptoms of asthma and rhinoconjunctivitis will therefore be more severe and more prolonged because of interaction between heavier pollen loads and increased air pollution.

There will be increasing amounts of robust allergenic plants and an increasing aeroallergen load for patients with inhalant allergy. In addition to affect respiratory allergies, insect allergy may be more frequent and more severe due to the introduction of new species or migration of stinging and biting insects into new environments. New food proteins might also give rise to food allergies.

Thunderstorms in spring and summer are related to hospital admissions for asthma exacerbations. Warming temperatures promote production of ground level ozone, which worsens asthma and airways hyperreactivity. Air pollution episodes, sandstorms in some countries and extreme weather events all interfere with allergy manifestation especially pollen related.

Currently, greenhouse gas mitigation is a global recommendation for stabilizing the climate. We all must be involved in development of prevention laws and regulations to ensure adequate health protective standards globally.


  1. D’Amato G, Rottem M, Dall R et al. Climate Change, Migration, and Allergic Respiratory Diseases: An Update for the Allergist. WAO Journal 2011; 4:121–5.
  2. D’Amato G, Cecchi L, Liccardi G. Thunderstorm-related asthma: not only grass pollen and spores. J Allergy Clin Immunol. 2008;120: 530–32.
  3. Malbe B,Shea KM, Truckner RT, Weber RW, Peden DB. Climate change and allergic disease. J Allergy Clin Immunol. 2008;122:443–5

Nelson Rosario, MD, PhD, FAAAAI
Allergy University of Parana
Curitiba, PR, Brazil

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