Immunotherapy: Allergen Desensitisation


Allergy management has always involved avoidance of what you are allergic to in combination with treating the symptoms. For example, in allergic rhinitis triggered by dust mite sensitivity special mattress covers and low allergy pillows are advised in combination with medications such as antihistamines and steroid nasal sprays. However, while such avoidance measures and treatments may be effective they do not alter your allergy itself. In other words, you remain allergic to house dust mite and will still get into trouble if the avoidance measures and treatments are discontinued. This means many years or even a lifetime of taking anti-allergy tablets, sprays, inhalers or even courses of steroids for more severe flare ups. Now a relatively new therapy (or rather an old therapy updated) offers the chance to desensitise you to your allergy and eliminate your symptoms.

What is Immunotherapy?

Immunotherapy is where you take a tiny dose of exactly what you are allergic to in a pharmaceutically modified form so that it is safe and effective. This generates immune tolerance to the allergen and thereby desensitises you to your allergy. The effects typically last for life.

Immunotherapy is not a new treatment and is available worldwide in injectable and oral forms for a wide range of allergens. It is especially helpful for hay fever, as well as perennial nose, eye and chest allergy caused by house dust mite. At Allergy Ireland, our doctors use the following oral licensed Immunotherapies:

Advantages of Allergen Immunotherapy:

  • Provides long term and even lifelong relief from symptoms. 
  • Reduces nose, eye and chest sensitivity to allergic irritation.
  • Reduces the amount of medication needed for comfort and relief.

How is immunotherapy administered?

A sublingual tablet is dissolved under the tongue once daily. Treatment courses are typically for 3 to 5 years. This may sound like a long time but if it significantly improves symptoms, reduces the use of other medicines and possibly even results in a final cure it is worth the time and effort.


Allergen Desensitisation Immunotherapy is considered a very safe treatment. As the medication only consists of modified allergen it can even be continued in pregnancy. The first dose is taken under medical supervision in Allergy Ireland but the rest of treatment course is taken at home.

Common mild side effects which can occur include itching in the mouth, swelling of the lips or abdominal cramps. Typically these symptoms can be prevented with a daily anti-histamine for the first few months of treatment. Less commonly, existing allergic rhinitis, asthma or eczema may be exacerbated. If this does happen please ensure to let us know so that we can make adjustments. This would typically settle within the first few months of treatment but treatment would need to be discontinued if it didn't.

What age groups is allergen immunotherapy used for?

Grazax (grass pollen) and Oralair (grass pollen) is licensed for use over the age of 6 years.

Acarizax (dust mite) is licensed for use in 12-65 year olds. 

Itulazax (tree pollen) is licensed for use in 18-65 year olds.

Based on our experiences in Allergy Ireland, we would feel that the benefits are most pronounced in those under the age of 30. Immunotherapy can be used in older patients too but the results are less certain in this group.

Potential Issues

It sounds exciting and is a real alternative to drops, sprays, inhalers and anti-allergy tablets. And yes, it does seem to offer some long term solution to what is definitely going to be a long term problem. But are there side issues I should be considering?

Absolutely, and here are some problems we have to consider and which we would like you to consider.

  1. How good are you (your child) at following daily routines with medicine? Is it a battle? By starting another daily therapy is there the possibility you’re adding an additional problem?
  2. If the treatment is going to last 3-5 years, how committed are you and your child to that length of therapy? If your son is an obedient 12 year old today could he be a rebellious and possibly anti-medicine 15 year old as therapy progresses? It is important to consider how attitudes may change with time and maturity. 
  3. Immunotherapy targets the allergic factor in nose, sinus, skin and chest conditions. However, often there are other triggers in these conditions. For example, smoking causes rhinitis symptoms so if you don't stop smoking this will reduce the overall effect of using immunotherapy.


In summary, undertaking a course of immunotherapy requires patience, commitment and attention to other trigger factors to ensure the best results. Our doctors will ensure that before rushing into starting treatment patients consider all of the issues outlined above so that you make an informed decision that's right for you.

Further Information