It’s difficult to ignore the symptoms of allergic rhinitis. Visits to the chemist to stock up on antihistamines and decongestants repeat year after year.
According to the 2007-2008 National Health Survey results published in the Australian Bureau of Statistics Year Book last year, 17 per cent of adults and 17 per cent of young adults (15-24 years) in Australia are affected by allergic rhinitis, commonly known as hay fever. The prevalence of allergic rhinitis has doubled over the last 10 to 15 years.
Climate change is expected to have a major influence on the increased prevalence of allergic rhinitis. The condition has an enormous effect on Australian society with many people taking sick days, spending money on medication and visits to the doctors, specialists, and hospitals.
The symptoms of allergic rhinitis are caused by the body’s reaction to inhaled pollen. With susceptible individuals, the body’s immune system mistakes pollen for a harmful substance and produces an antibody called immunoglobulin E (IgE). IgE results in the release of chemicals including histamine, leukotrienes and prostaglandins which cause the symptoms of allergic rhinitis.
Unlike the common cold or influenza, allergic rhinitis isn’t accompanied with a fever, and symptoms may last for weeks or months on end. Itchy eyes and nose also distinguish the condition from cases of a cold or influenza. Other symptoms of allergic rhinitis include, nasal congestion, runny nose, sneezing, itchy ears, throat and palate, as well as irritable and watery red eyes.
Allergic rhinitis sufferers frequently have other allergic conditions such as asthma or allergic conjunctivitis. The condition can also lead to sinusitis and otitis media (middle ear infection).
Different pollination times for different plant species influence the occurrence of the allergic rhinitis season. Pollination begins with trees in late winter / early spring, followed by grasses throughout spring and summer. Weeds have an extended season from August to May.
Observing the daily Melbourne Pollen Count during hay fever season is one way to inform yourself about the risk of allergic rhinitis on any given day. The University of Melbourne, together with The Asthma Foundation of Victoria, provides the service to media outlets from October 1 to January 31 the following year. On high risk days, allergic rhinitis and asthma sufferers can take cautionary measures to reduce pollen exposure, including staying indoors, wearing sunglasses and bathing their eyes.
According to University of Melbourne’s Professor Ed Newbigin, the Melbourne Pollen Count monitors grass pollen because it is the number one cause of hay fever in the city.
Professor Newbigin believes the amount of rainfall over the next couple of months will have an impact on the upcoming allergic rhinitis season.
‘If we get good rains over the next month or two, then the coming grass pollen season could be quite a bad one for hay fever sufferers as the rains will promote grass growth’, says Professor Newbigin.
‘However, a hot, dry spring and early summer will reduce the amount of grass pollen in our air and result in a relatively light season.’
There are many treatment options available for allergic rhinitis. The Australasian Society of Clinical Immunology and Allergy (ASCIA) lists the different types of medication available on their website, including antihistamines, corticosteroids and immunotherapy.
Immunotherapy, now in use for 100 years, is the only treatment that successfully treats the cause of allergic rhinitis, with other medications only reducing the symptoms. Also known as desensitization, immunotherapy provides repeated doses of targeted allergen, helping the immune system to develop tolerance.
ASCIA also provides a list of unorthodox treatments where the claims of efficacy are not backed by scientific evidence. The list includes chiropractic therapy, acupuncture and modified diets. In the case of modified diets, ASCIA’s website states there is ‘no published evidence that dietary restriction has a role to play in allergic respiratory disease’.
The incidence and intensity of asthma and related diseases such as allergic rhinitis is expected to increase with climate change. Research conducted by scientists Dr Paul Beggs and Nicole Walczyk from Australia’s Macquarie University shows the higher CO2 concentrations and temperature extremes projected for the future may cause plants to produce new or greater levels of allergenic proteins.
‘From the research showing a number of changes in aeroallergens such as pollen and mould spores resulting from climate change, it seems clear that climate change will change the incidence/prevalence and intensity of asthma and related diseases such as allergic rhinitis’, says Dr Beggs.
In fact, research by Dr Beggs and Associate Professor Hilary Bambrick from The University of New South Wales suggests that climate change is responsible for the observed global increase in asthma prevalence in recent decades.
With environmental factors on a trajectory for more severe hay fever seasons, it is time for federal and state governments to take more action to mitigate the effects of climate change. This includes improving standards of care and easing the financial burden on those suffering from allergies, including allergic rhinitis.