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Three million Australian adults – 15% of the population – struggle through spring and summer with watery eyes, running nose, itchy throat and the hallmark hay fever symptom, sneezing.
When people with hay fever are exposed to particular pollens, their body mistakenly thinks this is a threat and triggers an allergic reaction. Inflammatory cells quickly release mediators such as histamine and that’s when the symptoms kick in.
In some people with hay fever, pollen allergens can trigger allergic symptoms in the lower airways as well as the nose, making it difficult to breathe. Under certain climatic conditions, such as after thunderstorms, pollen allergy can trigger asthma attacks, even in those without a history of asthma.
Hay fever can have a profound effect on our ability to function normally. The problem seems to be getting worse, or at least consumers are increasingly looking to alleviate their symptoms. In the ten years to 2010, the wholesale turnover of drugs to treat hay fever doubled.
Why you have it
Grass pollens are the major outdoor allergen trigger for hay fever in Australia. The timing and severity of the grass pollen season varies considerably between years and places, according to a recent analysis of 17 sites across Australia and New Zealand.
With a temperate climate, Melbourne usually has a short but intense grass pollen season, peaking late in spring (October to November). In Hobart, the grass pollen season peaks slightly later and the pollen load is low.
In contrast, Brisbane and Darwin have grass pollen seasons extending most of the year, with peaks in summer for Brisbane (January to March) and in the dry season in Darwin (May and June).
Adelaide, Sydney and Canberra have the temperate grass pollen season in spring but also have secondary peaks in summer. These late summer peaks in grass pollen are likely to be due to subtropical species.
Australia is yet to establish a standardised network to monitor the timing and magnitude of pollen exposure. Levels of airborne pollen are influenced by weather and other factors affecting pollen production. Predictions of airborne pollen in the absence of actual pollen counts are therefore inaccurate and unhelpful.
Beyond biology, location and flowering times, patients with hay fever in Australia also show region-dependent patterns of allergic responses to subtropical and temperate grass pollens. This can affect the diagnosis and treatment of grass pollen allergy in Australia and elsewhere.
Just because you suffer from hay fever, doesn't mean you have to swear off flowers for life. These are the best varieties for those with allergies:
Managing your symptoms
A number of oral medications, nasal sprays and eye drops to treat hay fever are available over the counter at pharmacies. They work in different ways and have different pros and cons.