HOW TO STOP ALLERGIES RUINING YOUR LIFE from hay fever and eczema to pets and food
Why hay fever can strike – even when pollen count is low
IT’S long been a cruel mystery for many hay fever sufferers: why should they be hit badly on days when the pollen count is low?
But now British scientists have found that the solution lies in the particular type of pollen in the air.
There are types of grass which will greatly irritate some sufferers even without releasing huge quantities of particles.
The breakthrough finding also addresses the opposite phenomenon that some sufferers have a surprisingly mild allergic reaction on days with high pollen counts.
This is explained by species which can release large amounts of pollen, yet cause only low-level reactions for people with certain DNA.
The team of experts from universities and research institutions across the UK hope that their landmark study, called PollerGEN, will eventually lead to personalised pollen forecasts, based on the exact species that each hay fever sufferer is allergic to.
Until recently it has been almost impossible to differentiate the pollen from the scores of British grass species just by looking at them down a microscope, as they appear very similar. All grass pollens have therefore been lumped in together to give a single measure or ‘load’.
However, thanks to a new way of identifying pollens called DNA ‘barcoding’, they can now be distinguished from each other.
The academics are currently trawling through data on antihistamine prescriptions to see if spikes in prescriptions coincide with ‘peaks’ of pollen release from particular species. They are doing the same with figures on people taken to hospital in the summer because of asthma. The data should give them clues about which grass pollens are the most potent allergens.
Professor Simon Creer of Bangor University, who is leading the research, said: ‘I’m a hay fever sufferer myself and I know that, on some days – despite a high pollen forecast – I can be less affected than on other days when the forecast appears to be lower.
‘This led me and others to wonder whether it is the high load of pollen alone that causes the problem or whether the different grass pollens cause different levels of reaction.’
DNA barcoding expert Natasha de Vere, of the National Botanic Garden of Wales, said: ‘Some grass pollens are likely to be more allergenic than others for most people with hay fever.
‘But it’s also likely that different people have different responses to the same species. That being so, in the future we could test people to find out which grass pollens they are more allergic to.’
The information could then be used to create bespoke pollen forecasts, she said, based on knowledge about when different grass species release the bulk of their pollen, and each person’s inherent sensitivity to them.
The Met Office, which produces the pollen forecasts, is helping by mapping the geographical spread of common grasses.
Dr de Vere said warmer, more settled weather this Easter meant that both trees and grasses were releasing their pollen earlier than usual. Typically, the tree pollen season runs from late March to mid-May. The grass pollen season then takes over, lasting until July. This year, tree pollens have already peaked while levels of grass pollens are already rising, she said.