Asthma Management Handbook

Preventing thunderstorm asthma


Certain types of thunderstorms in spring or early summer in regions with high ryegrass pollen concentrations in the air can cause life-threatening allergic asthma flare-ups in individuals sensitised to ryegrass pollen (i.e. anyone with seasonal allergic rhinitis), even if they have not had asthma before.12, 3

People with allergic rhinitis and allergy to ryegrass pollen (i.e. most people with springtime allergic rhinitis symptoms) are at risk of thunderstorm asthma if they live in, or are travelling to, a region with seasonal high grass pollen levels – even if they have never had asthma symptoms before. This includes people with undiagnosed asthma, no previous asthma, known asthma.3 Lack of inhaled corticosteroid preventer treatment has been identified as a risk factor.3

Prevention of thunderstorm asthma in individuals is based on:

  • year-round asthma control
  • preventive inhaled corticosteroid treatment
  • avoiding exposure to thunderstorms on days with high ryegrass pollen levels
  • ensuring appropriate access to relievers during grass pollen season.

In this section


  1. Thien F, Beggs PJ, Csutoros D et al. The Melbourne epidemic thunderstorm asthma event 2016: an investigation of environmental triggers, effect on health services, and patient risk factors. Lancet Planet Health 2018; 2: e255-e63. Available from:
  2. Lee J, Kronborg C, O'Hehir RE, Hew M. Who's at risk of thunderstorm asthma? The ryegrass pollen trifecta and lessons learnt from the Melbourne thunderstorm epidemic. Respir Med 2017; 132: 146-8. Available from:
  3. Davies J, Queensland University of Technology. Literature review on thunderstorm asthma and its implications for public health advice. Final report. Melbourne: Victorian State Government Department of Health and Human Services; 2017. Available from: