One in five Canadians suffer from seasonal allergies, with the majority of us being hit hardest in the shoulder seasons, as grass and ragweed allergies, the two most common afflictions, hit in June-July and August-September.
Every year, there are dire warnings about the intensity of allergy season. However, Dr. Jason Lee, who specializes in clinical immunology and allergies in his private practice in Toronto, says that while overall pollen counts may fluctuate daily, they don’t vary dramatically year-over-year. Unless significantly more grass has been planted near you, your grass-allergy symptoms shouldn’t be that different from last year.
For anyone who has suffered an allergic reaction to airborne particles, the symptoms are hard to ignore: itchy eyes (and, sometimes, throat), runny nose, congestion and uncontrollable bouts of sneezing. According to Lee, these unpleasant reactions are the body’s way of getting rid of a foreign substance. “The best analogy is that your body is misidentifying something,” he says. Because your body thinks it’s fighting a parasitic infection, he adds, your immune system goes into overdrive in fighting off that infection.
There are a few ways to deal with seasonal allergies. The main strategy suppresses allergy symptoms, and the go-to treatment to this end is antihistamines. By blocking the effect of histamines (the chemicals that bind to your body’s cells and cause the subsequent inflammation and disagreeable symptoms), over-the-counter antihistamines blunt those symptoms.
However, a large-population study released earlier this year indicates that consistent antihistamine use over the long term may be a risk factor for Alzheimer’s disease. This finding has changed Lee’s stance on antihistamine use. “We recommend second- or third-generation antihistamines, which have fewer brain effects, such as sedation,” he says, adding that allergy sufferers should consult with their doctors, especially if they are using antihistamines daily in the allergy season.
Nasal steroids, which are prescribed medications that you spray up your nose just before and during allergy season, are the next line of defence. These products work in the same way as asthma treatments – by stunning the immune response. There are some concerns regarding the safety of these medications, with side effects ranging from headaches to nosebleeds. Notably, there’s also a small but significant risk of developing glaucoma and cataracts from daily use of nasal steroids. Regular eye exams are essential for anyone relying on nasal steroids.
Immunotherapy is a step up from symptom-specific treatments. By introducing small amounts of the offending particle gradually to your body, you can retrain your immune system to recognize that the particles are inoffensive and to ignore them rather than reacting dramatically. This therapy, Lee says “is essentially like sending your immune system back to school.”
There are two immunotherapy delivery systems: subcutaneous and sublingual. The first is a series of injections, scheduled pre-seasonally or taken all year long. The pre-seasonal shots are scheduled once a week over a nine-week period and are designed to deliver the offending pollen in minute amounts leading up to the launch of that particular allergen’s season. Patients with a grass allergy, for example, would start treatment in March.
Sublingual treatments, tiny tablets that disintegrate under your tongue, are new in Canada, but appear to be effective.
Year-round allergy shots, meanwhile, can be started at any time, with four or five months of weekly shots followed by monthly injections thereafter. “It’s a serious time commitment,” Lee says. However, he adds, the data is clear that this method works, with 70% of patients responding favourably and half of those finding they don’t need backup treatment, such antihistamines.
After five years of injections, patients are considered immune for life. Furthermore, this treatment has been shown to prevent the risk of asthma three- or fourfold. (Allergies are the top cause of this serious respiratory condition.)
There also is robust data indicating that immunotherapy can help to prevent any worsening of existing asthma symptoms. “You are not at the mercy of the pollen,” Lee says. “You don’t get the swings.”
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