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How to effectively control pollen allergies

May 12th, 2022
Cédric Lalonde, Pharm.D.
Cédric Lalonde, Pharm.D.
Pharmacist, Genetics Consultant

Seasonal rhinitis, also known as hay fever, is an allergic reaction caused by exposure to pollen. The immune system mistakenly considers pollen a pathogenic, dangerous organism and triggers an inflammatory response. Hay fever currently affects 17% of adults in Quebec and has increased significantly over the past 30 years, mainly due to the impact of climate change on plant species.[1] In particular, the combination of warmer temperatures and higher concentrations of atmospheric CO2 lengthens the growing season of allergenic plants, increases pollen production by plants and increases the allergenic potential of pollen.[2]

As a result, more people have contact with pollens, and those who are allergic to them see their symptoms become more frequent and more intense.

Allergens that vary according to the time of year

Although not the only allergen responsible for seasonal allergic rhinitis, ragweed pollen is the leading cause of this reaction in northeastern North America in summer and fall. It is estimated to account for up to 90% of seasonal allergies.[1] Therefore, it is of particular concern to the Quebec public health network.

However, it is not the only allergy risk; other potentially allergenic pollens are also present during the spring bloom.

Period Allergen
March - June Pollen from trees and shrubs
May - October Pollen from grasses (such as grass and hay)
July - October Pollen from ragweed

Recognizing allergy symptoms



In addition, cognitive function can sometimes be greatly affected (irritability, fatigue and sleep disturbance), which affects the quality of life of those affected [3]. Asthmatics should pay particular attention, as uncontrolled seasonal rhinitis may exacerbate their condition.

Ten tips to reduce exposure to allergenic pollens

The Quebec Ministry of Health and Social Services has recognized the problem. In 2015, it implemented the Stratégie québécoise de réduction de l’herbe à poux et des autres pollens allergènes, which aims to significantly reduce their health impact. Currently deployed in several regions, this strategy incorporates control measures into municipal grounds maintenance practices.

Although promising, government action remains limited. That's why everyone sensitive to pollen should protect themselves. A few simple measures can help build an effective barrier against allergens:

  1. Prevent ragweed from growing on your property. Use mulch or ground cover with no grass or plant other vegetation.
  2. Pull up ragweed as soon as you see it (by hand or with a garden tool) and dispose of it with the garbage (do not put it in the compost as it may contaminate it).
  3. Check your local Allergy Outlook and avoid going outside when pollen counts are high (often in the morning, on hot, dry or windy days).
  4. Avoid areas with high pollen counts (fields and untended land).
  5. Do not dry your clothes outside during troublesome periods.
  6. If possible, keep your home and car windows closed.
  7. Use an air conditioning system that recycles the air in your home or has a pollen filter (beware of air exchangers that can allow pollen into your home).
  8. Change your clothes and wash up as soon as you get home to eliminate pollen particles on your hair and skin.
  9. Flush your nose with a saline solution.
  10. Avoid contact with other irritants, such as tobacco smoke, moulds, and fumes from vehicles and factories, which can aggravate allergy symptoms.

The various treatment options

Seasonal allergy medications

For the most common symptoms, feel free to ask your pharmacist for an assessment of the various treatments available for your condition:

  • Second-generation oral antihistamines such as cetirizine (Reactine®), desloratadine (Aerius®) and loratadine (Claritin®) are first-line treatments to reduce runny nose, itching and sneezing [4]
  • Topical nasal corticosteroids reduce nasal passage inflammation
  • Topical antihistamines (nasal or ocular) are helpful as a supplement or for more isolated symptoms in some people. Some are available over the counter, while others require a prescription from a doctor or pharmacist.

What about diphenhydramine (Benadryl®)? Although many people use this first-generation antihistamine to relieve their seasonal allergy symptoms, it is not an optimal choice. It is often less effective and causes more side effects than second-generation antihistamines.

Desensitization protocol

If over-the-counter medications do not provide relief, testing for specific allergens with patch tests or serum immunoglobulin E may help determine the appropriate treatment.[5]

Depending on the results, the doctor may suggest a desensitization protocol. This treatment aims to reduce the body's sensitivity to the substance causing the allergy, thus significantly reducing allergic reactions. It consists of administering a small dose of the substance to which the person is allergic. Over several months or years, the dose gradually increases from one visit to the next. This approach may provide long-term benefits, even after the treatment ends.

Getting ready to enjoy the summer

With global warming accelerating, seasonal rhinitis is likely to affect more and more people and with greater intensity. Therefore, it is essential to act preventively and take advantage of the many solutions available to minimize the effects of allergens. 

That way, you'll have better protection and enjoy the summer more, whether in the city or the countryside.

For professional support, we’re here.

We offer services that can help your doctor screen for more than 650 allergens.

If you have any questions or would like more information, contact our customer service number at 1-833-590-2712.

  1. Isabelle Demers et Pierre Gosselin (April 2019). “At-a-glance – Pollens, climate and allergies: Quebec initiatives,” Health Promotion and Chronic Disease Prevention in Canada: Research, Policy and Practice, Vol. 39, #4, 
  2. Institut national de santé publique du Québec. “Mon climat, ma santé,” (accessed May 3, 2022).
  3.   Government of Quebec. “Seasonal rhinitis (hay fever),” (accessed May 3, 2022).
  4.   Roxanne Labrosse (May 6, 2019). “Les allergies saisonnières et la désensibilisation aux aéroallergènes,” Association pulmonaire du Québec,
  5.  J. Bousquet, N. Khaltaev, A.A. Cruz et al (April 2008). “Allergic Rhinitis and its Impact on Asthma (ARIA) 2008 update (in collaboration with the World Health Organization, GA(2)LEN and AllerGen),” Allergy, Vol. 63, Supp. 86, pp. 8-160,
Cédric Lalonde, Pharm.D.
Cédric Lalonde, Pharm.D.
Pharmacist, Genetics Consultant
Holding an undergraduate doctorate in pharmacy, Cédric Lalonde is a consultant in pharmacogenetics who has contributed to ground-breaking projects in pharmacy and participated in multiple healthcare bills. He is an associate clinician at Université Laval and the Université de Montréal and contributes to research and development in pharmacogenetics. His interest in teaching and popularizing science has led him to give numerous training courses and conferences. In 2022, he won the Jean Coutu Commitment Award for the commitment and creativity he has demonstrated within the pharmacy network.