Pollen desensitization

Pollen desensitization can be an interesting option to reduce the impact of seasonal allergies. Here is some information on the subject.



Allergies occur when the immune system becomes abnormally sensitive and overreacts to substances that are generally harmless. Pollen from trees and plants are the cause of allergic rhinitis, also called seasonal allergies. Each year, 20 and 25% of Canadians experience seasonal allergies, which can vary in nature and in intensity. Nasal symptoms (runny nose, congestion, sneezing, etc.) are sometimes accompanied by other symptoms (itchy eyes or throat, watery eyes, coughing, etc.).

All too often, seasonal allergies have repercussions on functioning and on quality of life (insomnia, fatigue, depression, concentration problems, etc.). They can also be accompanied by medical complications (worsened asthma, sinusitis, ear infections, etc.). Faced with this unpleasantness, people look for solutions to resolve these issues.



Taking charge of seasonal allergies is generally based on a three-pronged approach:

  1. reduced contact with pollen
  2. the use of medication to ease symptoms, and
  3. pollen desensitization (immunotherapy)

Immunotherapy is currently the only treatment that favourably modifies the natural evolution of seasonal allergies.



Immunotherapy or pollen desensitization treatment, consists of administering repeated pollen allergenic extracts (i.e. grass, ragweed). This method aims to prevent or eliminate allergy symptoms by making the immune system less hypersensitive to allergens, hence the term "desensitization". This treatment is available by injection or sublingually. This text focuses on the sublingual format.



Immunotherapy is specifically designed for people with allergic rhinitis (for at least two pollen seasons) who do not adequately respond or tolerate conventional treatment. The diagnosis of allergic rhinitis must be confirmed by the presence of symptoms, a positive skin test, and an allergen-specific immunoglobulin blood test for a particular type of pollen.

Therefore, pollen desensitization is not suitable for everyone. It is contraindicated for people who are immunocompromised, who have cancer, suffer from serious or unstable asthma, are under five years of age or take various medications (i.e. beta blockers). Your doctor will help you weigh the benefits against the possible risks if you are considering this type of treatment.



When a treatment is administered sublingually, the first tablet should be taken under the supervision of a doctor and the patient should remain under observation for at least 30 minutes. This precaution is to ensure that any adverse reaction to the drug is detected and managed quickly. If the person reacts well, the remaining doses can be taken at home.

Treatment, especially at the beginning, can cause allergy symptoms due to exposure to the allergen. These symptoms can often be relieved with antihistamines, but in the event of a strong reaction, it is advisable to stop treatment, consult a doctor, and wait for instructions to be given before resuming treatment. 

Other side effects of treatment may include:

  • swelling or itching of the mouth
  • throat irritation
  • itchy eyes, throat or nose
  • headache
  • nausea

Your doctor and pharmacist can provide additional information and explain what to do if you have any side effects.



Desensitization treatment must always be prescribed and initiated by a doctor who specializes in the treatment of allergic respiratory diseases. Sublingual treatment should begin two to four months before the start of the pollen season and continue throughout the season. The recommended dosage is one tablet to be dissolved under the tongue once a day. Avoid swallowing for at least one minute, and do not eat or drink for five minutes after taking the medication.

he benefits of immunization start to be felt in the first year and last for the duration of the treatment. The benefits may even extend beyond the treatment period, if the treatment has been properly followed. In the long term, allergy symptoms may reappear, and in some cases, a return to immunotherapy may be considered.

Desensitization treatment requires discipline, supervision and ongoing medical monitoring. Speak to your pharmacist for additional information on immunotherapy. They can advise you on how to use the medication optimally and safely. It is recommended to read the consumer information leaflet found in each product box.


Send to a friend

Pollen desensitization

Pollen desensitization can be an interesting option to reduce the impact of seasonal allergies. Here is some information on the subject.
Pick up in store
Please click on Search to display the results.
Store change