Hay fever season – it’s nothing to sneeze at
Got the sniffles, but it’s not the flu? It could be hay fever and here’s what you can do.
An estimated 4.6 million Australians experience hay fever.
If you are one of them, then your immune system is in overdrive detecting pollen allergens — proteins on and inside the pollen grain — and trying to force the pollen out while triggering inflammation, which is expressed as sneezing and runny and puffy eyes.
The scientific name for hay fever is allergic rhinitis, and pollen is not the only culprit — dust mites or tiny flecks of skin and saliva shed by cats, dogs, and other animals with fur or feather can also spark the immunity reaction.
The Australian Capital Territory and Victoria are the worst places to be for hay fever sufferers, and the Northern Territory has the lowest rate.
Seniors are not the worst hit — hay fever prevalence tends to diminish as we age after peaking in the 35-45 age group. Women tend to experience it more than men.
The native wattle tree is often blamed because its pollen gets everywhere. Yet the tree is pollinated by insects, so the pollen grains are heavy and cannot be carried far by the wind.
It might not even be the grass growing that is making you sneeze.
Look further afield — grass pollen can travel hundreds of kilometres at speeds up to 15 kilometres an hour.
For instance, Melbourne, which is forecast to have a bad hay fever season, has pollen blown in from farmlands far north of the city.
The pollen problem intensifies with thunderstorms, as that city found out in 2016.
Kira Hughes, a PhD candidate at pollen counting and forecasting facility Deakin Airwatch, explains that pollen grains are too big to travel further than our upper airway — our nose, mouth, and throat.
But they are full of tiny starch particles, sometimes hundreds of them — a bit like a beanbag filled with beans, Ms Hughes says.
In the hot humidity of a thunderstorm, the pollen grain beanbag can rupture and spill its starchy "beans".
"All those little 'beans' are covered with allergens, and because they're so tiny, they can get into your lower lungs and cause those severe asthmatic symptoms."
Hay fever treatment
There are several treatments available for allergic rhinitis, many of which do not require a prescription from a doctor.
Common medicines are intranasal corticosteroids (nasal sprays) and oral antihistamines.
For persistent and moderate-severe hay fever, guidelines recommend nasal sprays as the first-line therapy. For mild intermittent allergic rhinitis, antihistamines are recommended.
Our spending on hay fever medicines doubled between 2001 and 2010, going from $107.8 million to $226.8 million per year.
Experts predict hay fever could get worse. Climate change is affecting when plants release their pollen.
Some plants use temperature as their cue to start making pollen. When it gets warm enough, they start pumping it out.
As temperatures creep up, some plants start making pollen earlier or keep producing it later than usual.
Those plants that thrive in warmer areas will spread from the tropics towards the poles or higher elevations, potentially exposing people to new pollens and new allergens.
Plants use carbon dioxide as part of photosynthesis to make sugar, which they can use as energy.
Scientists suggest putting more CO2 into the atmosphere fertilises plants and produce more pollen.
Greenhouse studies show that higher levels of CO2 can increase some species' pollen's "allergenicity" — in other words, it becomes nastier for those of us with hay fever and asthma.
For instance, ragweed is a major cause of seasonal hay fever in the US and Europe and grows as a weed in southeast Queensland and northern New South Wales.
One study grew ragweed in CO2 concentrations projected for the middle of this century and found those plants made pollen that contained more allergen than ragweed grown in today's conditions.
For further reading: AIHW, ABC, Hay fever survival guide and Health Direct
