Immunotherapy involves the regular administration of gradually increasing doses of an allergen extract over a period of years. The extract contains standardised amounts of the “allergen” or the substance that is causing the unwanted allergy symptoms. It works by changing the way the immune system reaction to the allergy, effectively allowing the patient to tolerate the allergen without symptoms. It is a significant commitment and the process will involve the patient needing to continue with treatment for 3 – 5 years.
It can be administered by:
- A subcutaneous injection given by your doctor. This will initially be weekly though the time between injections will increase to monthly over time.
- A sub-lingual (under the tongue) drops which need to be administered daily
- An oral spray which is administered daily.
Subcutaneous immunotherapy has been available for many years though the oral preparations have only been available in the last few years. Studies have shown that both the oral and injection immunotherapy are effective although the injections may be slightly more effective. The pros and cons of each option relate to cost, convenience and compliance.
The subcutaneous form is the cheapest to purchase though it does require a regular appointment with your GP to administer the injection. While it is initially weekly, within 3 months it would only be a monthly visit.
Oral and sub-lingual preparations are more expensive because the extract is more concentrated and they also require that the patient use the preparation every day for the entire period of the course of immunotherapy (which is a minimum of 3 years is usually closer to 5 years). If it is not possible to use it daily for whatever reason, this option may not be optimal for you.