Growing up on a farm seems to protect against allergy to pollen grains (Image: Larry Towell/Magnum Photos)
In some cases, yes. Sometimes they disappear of their own accord, and there are effective drugs for managing the symptoms, including tablets and nasal sprays.
For some poor souls, however, the symptoms never let up and even regular and correct use of these medicines isn’t enough to offer relief. That’s where a relatively new treatment called immunotherapy may help.
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Unlike antihistamines and steroid sprays, which merely dampen the immune system’s reaction to allergens, immunotherapy is designed to retrain it. In some cases allergies can be completely cured this way.
The treatment involves regularly exposing the immune system to high doses of the problematic allergen in order to desensitise it, although exactly how it works is unclear. The thinking is that when B-cells and T-cells in the lymph nodes are exposed to high levels of allergen, this prompts them to do a U-turn; instead of churning out chemicals that rally immune cells to their defence, they stimulate the growth of master immune cells called regulatory T-cells that dampen the response.
For now, most immunotherapies involve a three-year course of weekly injections into the fatty layer beneath the skin, or tablets placed beneath the tongue. This makes it time-consuming and expensive and means that many people stop before treatment is completed, or aren’t offered it in the first place.
“If everything is done right, injected immunotherapy is extremely effective,” says Hal Nelson, senior staff physician at National Jewish Health in Denver, Colorado. “But I think it’s safe to say that it’s rarely a lifetime cure. People can relapse, and the duration of remission will vary from individual to individual.”
However, there’s nothing to stop people going back for another course, and there’s some evidence that the treatment doesn’t need to be as prolonged the second time around, he adds.
What’s more, two pilot studies have suggested that it’s possible to induce tolerance to cat and grass allergens with just three injections into a lymph node in the groin. Other trials are investigating the use of skin patches or modified allergens that could be given in higher doses for shorter periods.
There’s even hope that immunotherapy could halt the sensitisation process in its tracks in children who are likely to develop allergies – those with a family history or who have eczema, for example – but haven’t yet developed symptoms. “We think that treating with immunotherapy early on would put a check on that progression to other sensitivities and worse disease,” says Davies.
There are other things that parents can do to reduce the chances of their children developing hay fever. Breastfeeding is thought to help protect against all allergies, but it’s no panacea. Children living in rural areas seem to get less hay fever than those growing up in urban areas. “The best thing you can do for your children to stop them getting allergy is to expose them to a cowshed for 1 hour in the first 6 months of life,” says Durham.
“The best thing you can do to protect your children is expose them to a cowshed”
Read more: “Hay fever: Why it’s not to be sneezed at“
This article appeared in print under the headline “Can airborne allergies be cured?”
