Pollen desensitization

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

Seasonal allergies

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. Between 20 and 25% of Canadians are affected each year by manifestations of seasonal allergies, and can vary in nature and in intensity. Nasal symptoms (runny nose, congestion, sneezing, etc.) are sometimes accompanied by other symptoms (itchy eyes and throat, lacrimation, coughing, etc.).

Too often, seasonal allergies have repercussions on functioning and on quality of life (insomnia, fatigue, demoralization, concentration problems, etc.). Seasonal allergies can also be accompanied by medical complications (worsened asthma, sinusitis, otitis, etc.). Faced with this unpleasantness, people look for solutions likely to resolve these issues.

The search for solutions

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

  1. reduced contact with pollen
  2. the use of medication intended to relieve symptoms, and
  3. pollen desensitization

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

Pollen desensitization

Allergen immunotherapy or pollen desensitization treatment, consists of administering repeated pollen allergenic extracts (i.e. grass, ragweed). This method aims to prevent or stop 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 form.


Allergenic immunotherapy is particularly aimed at people affected by allergic rhinitis (for at least two pollen seasons) who do not adequately respond to conventional treatment or do not tolerate it well. The allergic rhinitis diagnosis must have been confirmed by the presence of symptoms, by a positive skin test, and by an allergen-specific immunoglobulin blood test for a particular type of pollen.

Therefore, pollen desensitization is not suitable for everyone. Moreover, it is contraindicated for immunosuppressed individuals, who are affected by 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 that you could reap and the possible risks if you are considering this type of treatment.

The risks

When a treatment is administered sublingually, the first tablet must be taken under the supervision of a doctor and the patient must remain under observation for at least 30 minutes. This precaution is intended to allow detection and rapid intervention of a potential undesirable reaction to the medication. If the person reacts well, the other doses can then be taken at home.

Especially at the beginning, the treatment can cause allergy symptoms due to exposure to the allergen. These symptoms can often be relieved by an antihistamine, but in the case of a strong reaction, it is advisable to stop treatment, to consult a doctor, and to wait for his/her instructions before resuming treatment. 

The treatment can also cause other side effects, such as the following:

  • swelling or itching of the mouth
  • nausea/vomiting
  • diarrhea, and
  • headaches

Your doctor and your pharmacist can give you additional information on the subject and explain what to do if these side effects occur.

Treatment modalities

A desensitization treatment must always be prescribed and initiated by a doctor specialized in the treatment of allergic respiratory illnesses. With regard to sublingual treatment, it must begin between two to four months before the start of pollen season and continue throughout. The recommended dosage is of one tablet a day. The benefits of immunization begin to be felt in the first year and last throughout the duration of treatment.

Desensitization treatment requires discipline, guidance, and sustained medical monitoring. Speak to your pharmacist for additional information about allergenic immunotherapy. He/she can provide advice so you can make optimal and safe use of the medication. It is recommended to carefully read the consumer information pamphlet included in each product package.


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Pollen desensitization

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