For the first time, scientists have discovered that measuring allergen levels in the air, rather than the traditional method of counting pollen, will significantly help hay fever sufferers preemptively prevent risks and eliminate debilitating symptoms. Hay fever, or seasonal allergic rhinitis, affects more than a quarter of U.S. adults and about 19 percent of children. Although symptoms such as sneezing, sinus pressure, itchy mouth and eyes, and nasal congestion have many similarities to cold viruses, they are triggered by pollen from trees and grasses. Pollen can also affect the severity of asthma symptoms in people with asthma, increasing wheezing, difficulty breathing and risk of attacks.
Researchers led by a team from King's College London and Imperial College London have discovered for the first time a more accurate way to determine how much pollen in the air affects hay fever sufferers on any given day.
"Grass pollen is the most common cause of hay fever," said lead author Elaine Fuertes of Imperial College London. "In this study, we measured levels of a grass allergen (Phlp5) and found that this was more consistently associated with allergic respiratory symptoms than grass pollen counts."
Pollen counting generally uses a rotating device to sample and physically measure pollen in a certain volume of air in real time. This approach, along with pollen forecasts (which estimate allergy risk based on data from previous years), has been a common way to analyze air quality around the world. But they are far from ideal.
Because each pollen releases different amounts of allergen, traditional pollen counts may incorrectly reflect the number of symptom-causing airborne allergens on any given day.
The scientists believe that by measuring Phlp5, they can gain a more accurate picture of the levels of active allergens, allowing hay fever sufferers to make more informed decisions about treatment and lifestyle.
For the study, researchers collected daily symptom and medication scores, as well as admissions to a London asthma hospital, from 93 participants in the PollenLITE clinical trial. They compared it to air samples, matched dates and locations, and measured the levels of the Phlp5 grass allergen protein.
Using blood analyses, symptom reports and medication use, the researchers found that while there was a link between daily pollen counts and allergic reaction severity, the link was more consistent and accurate when measuring Phlp5 levels.
Although it is difficult to accurately predict allergy risk at this time, combined with the Phlp5 assessment may be more accurate than a standard pollen count.
"High pollen season can be severe for hay fever sufferers, and people allergic to grass pollen may experience severe asthma attacks," said senior author Stephen Teale, professor of immunology and microbial sciences. "This study shows that there is a superior way to measure pollen allergens in the air than traditional pollen counting."
Researchers will now study whether conditions such as temperature, wind, humidity and pollution have an impact on how much allergen is released from each grain of pollen.
"Monitoring grass allergens, rather than grass pollen counts, gives results that are more consistent with patient symptoms and allows people with severe allergies to be better prepared during pollen season," Teal said.
The study was published in the Journal of Allergy and Clinical Immunology.