Experts claim hay fever among adults has soared during the past 15 years.
Common allergies including birch and timothy grass, both leading causes of hay fever, as well as adverse reactions to dogs and cats increased significantly among adults between 1994 and 2009, Swedish researchers found.
While most studies of allergies have focused on childhood, when the problems are most common, the new study is one of the first to focus on older people. It found that allergies to timothy grass increased from 12 per cent of adults to 21 per cent during the study period, while reactions to birch rose from 13 per cent to 18 per cent.
Allergies become less common with age, but even people in their fifties are at risk with 10 per cent now reacting to at least one common allergen in skin prick tests.
Environmental factors like increased urbanisation and air pollution have most likely contributed to the increasing prevalence of allergies, the scientists wrote in the Allergy, Asthma and Clinical Immunology journal.
Beverley Adams-Groom of the National Pollen Research Unit told Sky News that cleaner lifestyles could also be to blame because of their effect on our immune systems.
Climate change could also be playing a role because rising carbon dioxide levels allow plants to grow more efficiently and produce more pollen, she added.