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ALLERGY sufferers could be triggered by life events as new research suggests conditions such as hayfever could be "in the mind".

A new study found that some people suffer from allergic reactions even when there is no pollen in the air and that they could in fact be having "placebo" responses.

 New research suggests hayfever could actually be a placebo effect
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New research suggests hayfever could actually be a placebo effectCredit: Getty - Contributor

The study, published in the journal Proceedings of the National Academy of Sciences in the US, suggests that someone's symptoms might be caused by being in a place where they have previously been exposed to pollen.

Dr Luciana Besedovsky, from Harvard Medical School and the University of Tübingen, said an "allergic response can be triggered even in the absence of allergens by simply reencountering the environmental context in which an allergen was previously administered."

For the study, researchers recruited 25 men and administered triggers such as birch pollen and grass - all common allergies for people who suffer from hayfever - through a nasal spray.

To determine whether their reactions were genuine or in fact part of a placebo effect, the group were asked to return and carry out the experiment again.

However, this time they were given a harmless nasal spray of salt water, but were told that there was a 50 per cent chance that it contained pollen.

For some, simply being in the same room where they had originally been exposed to pollen did spur a reaction.

Experts noted a rise in an enzyme known as tryptase, which is produced at a higher level during hay fever as the immune system kicks in.

Smell triggers

They then wanted to test whether a similar reaction could be triggered by a smell.

The group were asked to sniff an almond-scented chemical before being blasted with pollen.

Scientists then asked them to repeat the experiment again at a later stage and noted that the scent triggered mild hay fever symptoms, such as sneezing, in some - even though there was no pollen around anymore.

Dr Besedovsky, first author of the study, said: "Our findings suggest if someone goes to a place where they usually have hayfever, like a park with lots of trees, they might have an allergic reaction.

"This might happen outside of pollen season because they have been mentally conditioned to associate that park with hayfever."

If someone goes to a place where they usually have hayfever, like a park with lots of trees, they might have an allergic reaction

Dr Luciana BesedovskyHarvard Medical School and the University of Tübingen

She added that while she is not claiming that people with hayfever make up the condition, it’s clear that there is a clear link between how the immune system responds to certain cues from the body.

The academic also suspected that sleep may help people store a memory which links an allergic reaction to a place.

To test this theory, half of the participants were asked to stay awake all night after the first experiment.

For those who had a good night's sleep, their tryptase levels only rose the second time after originally being exposed to the pollen.

 The graphic above shows the pollen levels for this week
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The graphic above shows the pollen levels for this week

However, most of the group had a rise in the enzyme when smelling the almond-scented chemical - regardless of whether or not they had slept.

Dr Besedovsky said: "These findings have important implications for understanding the often observed 'placebo' allergic responses occurring in the absence of allergens".

In conclusion to her findings, she said that sleep may actually be a contributor to the aggregation of allergies.

All participants enrolled in the test were not found to have any sleep disturbances before they began the trial.

She stated that people may have been "mentally conditioned" to associate a park with hayfever, therefore spurring on symptoms.

In the UK, around 13 million people are affected by hay fever with the pollen seasons typically kicking off in late March or early April.

The pollen count for this week across most of the county is at a moderate level, except in the north and Scotland where some areas will see high pollen concentrations.

Meanwhile, as the coronavirus pandemic in the UK continues, hayfever sufferers have also been growing concerned about their symptoms, some of which can be mistaken for the virus.

The two main symptoms of coronavirus are a high fever and a new continuous cough, whereas people suffering with hayfever will not have a high temperature and will not usually have aches and pains, another symptom of the virus.

Coronavirus or hayfever? How to tell if your symptoms really are Covid-19 as pollen season begins
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