Hayfever: How to beat this year's pollen bomb
Although it's only March the hay fever season has already started – and will last till October. With air pollution meaning more are suffering allergies...
EARLY signs of spring are especially welcome this year – unless you are one of the tens of thousands of hayfever sufferers in Northern Ireland, as it means that billions of pollen grains released by flowering trees and grasses are poised to bring misery.
And new research suggests the pollen season is lengthening, so people could get symptoms of hayfever for more of the year than they used to.
A US study published last month found that the pollen season lengthened by up to 30 days between 1990 and 2018. So instead of starting in mid to late March and ending in early September, it is starting in late February and finishing when autumn is well under way in October.
This isn’t just bad news for those with hayfever, it seems. Other research has indicated that, even in people who don’t have the allergy, pollen can suppress the way the body responds to viruses by reducing the immune response in the airways – with the risk of catching Covid linked to the amount of airborne pollen circulating.
Researchers at the University of Utah School of Biological Sciences looked at data from 130 pollen collection points in 31 countries on five continents —and found that Covid infection rates went up as pollen levels in the air rose.
Writing in the journal Proceedings of the National Academy of Sciences last month, they suggested this was because inhaled pollen reduced the airways’ inflammatory immune response to viruses including Covid, so viruses were able to take hold more easily.
The pollen grains reduce the production of proteins that would otherwise cause cells to heighten their antiviral defences in the nasal passages.
While more research on the potential Covid link is needed, there is no doubt that this hayfever season could be troublesome for the one person in four in the UK who have the condition.
hayfever, otherwise known as allergic rhinitis, is triggered by an allergy to pollen. The symptoms begin when immune cells called B lymphocytes (or B cells) mistakenly identify the proteins on pollen as a threat and make antibodies in response.
These allergen-specific antibodies (known as IgE) bind to mast cells, which play a key role in the immune response, helping to trigger inflammation for example, used to ‘kill off’ any invader.
We all have mast cells, which are found in the skin, lungs, nose, mouth, gut and blood. But for those with hayfever, during exposure to pollen, these sensitised mast cells trigger the release of powerful chemicals including histamine to rid the body of the ‘threat’.
Histamine makes blood vessels dilate – causing the characteristic stuffy nose – and prompts the release of fluid from tiny capillaries, triggering a runny nose, sneezing and red, itchy eyes.
Pollution is the new enemy
Most people have an allergy to tree, grass or weed pollen. "However, some unlucky people may suffer from two or all of them," says consultant paediatric allergy specialist Professor Adam Fox.
In a typical year, the tree pollen season begins first, starting in February and lasting until June. The grass pollen season starts in May and finishes in July. Weeds such as stinging nettles release pollen from June to September.
"If I look back at the past 20 years of my clinical practice in the UK, we have definitely seen an increase in the height and length of the pollen season," says Prof Fox.
"It used to be that there were good allergy years and bad allergy years but now they all tend to be bad. As I understand it, this is down to climate change and warmer temperatures."
In previous studies, experiments carried out in greenhouses found that increases in temperature and atmospheric carbon dioxide – hallmarks of human-caused climate change – can cause more pollen production, but the latest US research shows this is happening in the real world, too. It found that the pollen season in the US and Canada in 2018 started 20 days earlier than in 1990 and lasted 10 days longer, and there was 21 per cent more airborne pollen than there had been 28 years earlier.
A similar pattern is being seen in the UK and other countries in the northern hemisphere – warmer, earlier springs and longer, balmier summers are helping to lengthen the allergy season.
"The strong link between warmer weather and pollen seasons provides a crystal-clear example of how climate change is already affecting people’s health," says William Anderegg, assistant professor of biology at the University of Utah, who led the research.
There are other causes – the scientists behind the recent study estimated that climate change is responsible for about half of the pollen season lengthening, and about 8 per cent of the amount of pollen increasing.
But increased air pollution may also be to blame, as allergy specialist Dr Adrian Morris explains. "Many people don’t realise there is a higher proportion of hayfever sufferers in cities than in the countryside," he says.
This is because pollutants found more in cities, including diesel particles, irritate the lining of the airways and make them more sensitive.
"These tiny particles can penetrate right into the air sacs, deep within the lungs and set up an inflammatory response, so when an allergen such as pollen comes along, the airways are already primed," adds Prof Sir Malcolm Green, founder of the British Lung Foundation
A link to poor gut health?
It is not simply that the environment around us could be making allergies more likely.
Another factor might be better hygiene practices, which mean children’s immune systems are no longer so exposed to common bugs that help them mature and not overreact.
Modern diets may be implicated, too, potentially causing an imbalance in our gut bacteria (or microbiome) that has knock-on effects on the immune system.
"We have a growing body of evidence that suggests our immune systems are regulated by our gut microbiome, which can be influenced by many different factors, including whether you were born at home or in hospital, whether you were breast-fed and the use of antibiotics in early childhood," says Prof Fox.
Lack of sleep and brain fog
Non-sufferers tend to dismiss hayfever as unimportant but it can be really debilitating for a significant minority of people and affect their quality of life, says Prof Fox.
"As well as causing red, itchy eyes, streaming noses and sneezing, hayfever can also cause brain fog, which makes it harder to concentrate so you are not as effective as you should be."
The theory is that this brain fog results from poor sleep quality as you try to breathe at night through inflamed sinuses.
Up to 57 per cent of adults and 88 per cent of children with hayfever have sleep problems, including waking up dozens of times a night for brief periods. This in turn leads to daytime fatigue and decreased concentration, according to a study published in the World Allergy Organisation Journal.
Another possibility is that the inflammation affects the drainage tube in the ears, and when the middle ear is unable to drain properly the result is imbalance, dizziness and fogginess.
WHAT YOU CAN DO
Make a date to take your pills
If you know you suffer from hayfever, take action in advance, says pharmacist Sid Dajani.
"Corticosteroid nasal sprays, such as mometasone furoate (brand name Nasonex) or fluticasone propionate (Flonase) are available over the counter and can be used a week before symptoms begin," he says.
"These sprays are very effective in reducing the severity of symptoms because they help reduce local inflammation but it can take a little while for them to take effect.
"If you know you always get hayfever symptoms at a certain time of year, start using them in the two weeks running up to that time. Keep an eye on when your symptoms start one year and adjust the timing accordingly."
Wear a mask for gardening
"Ordinary [surgery-style] blue masks will help reduce the number of pollen grains entering your nose and mouth but sealed masks with vents filter out 95 per cent of particles in the air," Mr Dajani says.
He also advises against the common advice to smear Vaseline around your nose to ‘catch’ the pollen grains before their enter your nose: "It makes a sticky mess and doesn’t work."
Give your pets a wipe down
Most people know it is advisable to remove work clothes and shoes when you get home, to minimise the risk of bringing pollen in – but the same extends to your pets.
Dogs and cats can bring pollen inside on fur and feet, so keep a damp towel by the door and wipe them down when they come in.
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