Information summarised from Thunderstorm Asthma – Information Paper for Health Professionals, published by the National Asthma Council Australia.
What is thunderstorm asthma?
In people with allergy to grass pollens, thunderstorm asthma can be triggered by exposure to a high concentration of pollen fragments in wind gusts at the start of a thunderstorm. In Victoria, this mainly occurs in springtime or early summer, and is associated with high perennial rye grass pollen counts.
The world’s largest and most catastrophic epidemic thunderstorm asthma event occurred in Melbourne and Geelong in November 2016, on a day of extremely high airborne grass pollen concentrations. It resulted in a sudden large surge in emergency ambulance calls, thousands of emergency department presentations, and hundreds of hospital admissions. There were 35 intensive care admissions, an almost 10-fold increase in asthma-related hospital admissions, and a more than 6-fold increase in respiratory-related presentations to emergency departments, compared with the previous 3 years. Thunderstorm asthma contributed to 10 deaths, including 5 people admitted to an intensive care unit.
Who is most at risk?
Main risk factor
Seasonal allergic rhinitis (hay fever) occurring in springtime, with or without known asthma, or confirmed hypersensitivity to rye grass pollen (for example, positive skin prick test or high ryegrass-specific IgE), and exposure to outdoor air or wind gusts, at the start of, or later in, a thunderstorm, on a day with high level of airborne grass pollen.
Additional risk factors
- Current asthma (especially if poorly controlled)
- Not taking an inhaled asthma preventer containing corticosteroids (ICS)
- History of asthma
Possible additional risk factors for severe and life-threatening symptoms
- Asian or Indian ethnic background
- Young adult age group
What are the clinical guidelines for preventing thunderstorm asthma?
Patients with springtime allergic rhinitis (with or without asthma)
Advise patients to:
- Check for alerts about high airborne pollen counts during spring, using a reputable source, such as the Australian Pollen Allergen Partnership.
- Check official thunderstorm asthma forecasts in regions where provided, for instance using the Victorian Department of Health’s epidemic thunderstorm asthma risk forecast.
- Avoid being outdoors at the start of and during thunderstorms in spring and early summer, especially during wind gusts that precede the rain front.
Educate those without asthma to recognise and report possible asthma symptoms such as wheeze, tight chest, dyspnoea, and to know how to access a rapid-acting reliever if needed.
Patients with asthma
Prescribe ICS-based preventer treatment as indicated. Current national asthma guidelines recommend ICS-containing treatment for all adults and adolescents with:
- asthma symptoms twice or more during the past month
- waking due to asthma symptoms once or more during the past month
- an asthma flare-up in the previous 12 months.
For those allergic to grass pollens who are not already using ICS, prescribe preventive ICS-based treatment in springtime – start at least 2 weeks before exposure to springtime high pollen concentrations and thunderstorms, and continue throughout the grass pollen season.
Update written asthma action plans regularly and ensure patients always have access to rapid-acting bronchodilator relievers.
What can your practice do to prepare for thunderstorm asthma?
- Consider having a clinical meeting about thunderstorm asthma so clinicians’ awareness can be raised, and they can be updated on the management of thunderstorm asthma.
- Display posters or information in your waiting rooms about thunderstorm asthma.
- Circulate the National Asthma Council Australia’s thunderstorm asthma information paper for health professionals to your clinical team.
- Use Pen Clinical Audit Tool (Pen CAT) to identify patients with allergic rhinitis and offer them a thunderstorm asthma preventative appointment.
- Use Pen CAT to identify patients with asthma not on a preventive inhaled ICS and offer them a thunderstorm asthma preventative appointment.
- Send out an SMS to all patients with asthma and allergic rhinitis with information on thunderstorm asthma with links to check for pollen alerts.
- Consider developing an asthma action plan with patients who have allergic rhinitis or rye grass pollen allergy despite no known asthma.
- Discuss and raise awareness of risks with patients who have asthma, allergic rhinitis, and ryegrass pollen allergy and check that they have access to preventers and relievers as part of their asthma plan.
Ensure at-risk patients are aware of their nearest Priority Primary Care Centre, and the contact details of the Victorian Virtual Emergency Department. Advise them to use these should they require urgent care after-hours or on weekends when the practice isn’t open.
Remind them to call 000 in an emergency.
For more information
- HealthPathways Melbourne – Asthma in Children and Adolescents
- National Asthma Council of Australia – Thunderstorm Asthma Thunderstorm Asthma – information paper for health professionals
- Royal Australian College of General Practitioners – Emergency planning and response in general practice, fact sheet: thunderstorm asthma
- NWMPHN – Childhood asthma management