Hay fever: The new wave of effective cures for seasonal allergies

Is it possible to train the body to resist seasonal allergies? That's the hope promised by a new line of immunotherapy that is reviving an old treatment.

Glenis Scadding still remembers one of her first patients for sublingual immunotherapy, forty years later. His hay fever was so debilitating that he couldn't walk to the local train station without wheezing. Scadding's treatment involved desensitising the patient to the culprit of his allergies, birch pollen, with drops under his tongue.

"He turned up at my house with a case of wine, because I had completely altered his life in the spring," says Scadding, vice president of the non-profit Euforea and honorary consultant allergist and rhinologist at University College Hospital London, UK.      

"And then I got so much flack, I stopped."

More than 400 million people worldwide experience allergic rhinitis – inflammation of the nasal passages from a reaction to airborne allergens. It happens when your immune system mistakenly identifies something like animal dander or dust mites as harmful, triggering symptoms that can include a runny nose, itchy eyes, sneezing and – at its worst – breathing difficulties. When it's seasonal, such as in response to pollen, allergic rhinitis is called hay fever.

As well as affecting quality of life, hay fever can have severe long-term consequences, including the risk of developing both respiratory infections and asthma. 

Plus, it affects a lot of people. In the UK, around one in four adults and one in eight children have allergic rhinitis, leading to at least 16 million doctor's office visits per year, with similarly high figures in Australia and the US. And that number may be growing: studies find an increase in prevalence over time in regions including Europe, the US and Australia. There is also growing evidence that hay fever symptoms are becoming more severe with climate change.

Yet there is good news, say allergists: high-quality, effective, and safe therapies are now available for hay fever. Most treat symptoms. But one, allergen immunotherapy (AIT), is more of a cure, "teaching" the body to react less to certain allergens, and it may re-route the common hay fever-to-asthma pathway.

Far more people could benefit from these treatments than are receiving them. "Very few people get to see the right person to treat their disease – and they don't get to see them at the stage when the disease is early, uncomplicated and easy to treat," says Scadding.

A serious health concern

Part of the problem is that even health professionals don't always take allergic rhinitis seriously, says clinical allergist Stephen Durham, emeritus professor of allergy and respiratory medicine at Imperial College London and Royal Brompton Hospital. General practitioners often tell patients just to go to the pharmacy for an antihistamine, for example, rather than referring them to an allergist or considering something preventative and long-term, like allergen immunotherapy, he says.

"Hay fever is a major problem, and it's often trivialised by those who don't have it," Durham says. "If you think about what we do in life, we work, we sleep, and we have fun. And all of those things are seriously impacted by hay fever."

Hay fever sufferers are more likely to have difficulty falling and staying asleep, to feel fatigued and to wake frequently at night, for example. Seasonal allergies have even been found to impact children's academic performance.

There can be other health consequences, too. Because their mucous membranes are chronically inflamed, people who have an allergy experience more respiratory infections – up to twice as many, according to one study. When it isn't adequately treated, hay fever can cause severe, chronic upper airway disease and ear infections.

Hay fever, particularly in children, can also lead to the development of asthma, and asthma itself tends to be more severe among people who also have hay fever. "There's a concept of 'one airway, one disease'," says Barrie Cohen, a paediatric allergist in New Jersey, US and author of a 2023 American Academy of Pediatrics review on allergic rhinitis. Inflammation in the upper airways can influence the lower airways........

© BBC