When allergies turn dangerous
Tuesday, March 20, 2018, 12:00 PM - Allergy sufferers are no strangers to the nuisances of the season. But for some, the runny nose and red eyes can combine with asthma to make things even worse, potentially even life-threatening if left untreated.
Dr. Gina Lacuesta of Dalhousie University’s Department of Medicine, says allergic reactions to pollen can worsen symptoms in asthma sufferers.
“The main link with seasonal allergies is, if they have a lot of upper airway symptoms, they won’t be able to use their usual nasal functions, which is to filter, clean, warm, humidify the air,” she says. “If they don’t have that normal function in the upper airway, then it affects their air they breathe in their lower airway. So essentially, they’re getting dry, unfiltered, unclean air, and their asthma will exacerbate because of that.”
As for how many asthma sufferers may be at risk, it can be substantial.
Dr. Paul Keith, of McMaster University’s Department of Medicine, says around one in three people are prone to developing seasonal allergies and, of those, about one in three are at higher risk of developing asthma.
Dr. Keith says an attack can happen at any time, but most particularly if allergy symptoms in the upper airway are not kept under control. Some sufferers only experience symptoms during allergy season, while others may be prone to asthma all year around, but worse during a particular allergy season.
“There is data that thunderstorms can break up the pollens into smaller particles that can be more easily inhaled into the lungs, and that can cause asthma,” he says. “But also, if you have uncontrolled inflammation, a lot of nasal congestion in your upper airways, you’re more likely to get inflammation in your lower airway as well.”
Some asthma sufferers may eventually outgrow the condition, or may develop a tolerance over time to the allergens that worsen asthma symptoms. For the day-to-day, however, Dr. Keith says it’s important to keep on top of symptoms. Nasal steroids and immunotherapy can help in the long term, but Dr. Keith says research suggests vitamin D deficiencies can exacerbate the problem.
“If you live in Canada, where you’re likely to be vitamin D-deficient, and you have asthma and you are on a nasal steroid, it’s probably good to either take a vitamin D supplement or make sure you get sufficient vitamin D in your diet,” Dr. Keith says.
Allergy research has continued at a brisk pace, and Dr. Keith says sufferers of both allergies and asthma would do well to check in with their doctor to ask about new remedies, if they haven’t in awhile.
Dr. Lacuesta says, aside from systematic treatment with inhalers and similar remedies, modifying the disease process itself mostly relies on what she calls “desensitization”, which until quite recently has mostly been available in the form of allergy shots, gradually building up allergy resistance over time.
However, Dr. Lacuesta says new therapies are being developed, and one that is already available is “sub-lingual immunotherapy,” involving a tablet placed under the tongue rather than a course of shots. While the method has so far only been effective for grass and ragweed pollens, she says it’s likely to become more widespread.
“I think that kind of immunotherapy, once it becomes available for other things, like dust mites, the hope is if we intervene in children that we may actually be able to change the natural allergy progression that can sometimes happen, where they will develop asthma later on.”