Allergen specific immunotherapy or commonly known as allergy shots is the only true long term treatment to relief your allergy and allergy related diseases that can last even after completing a shot program. It is done by gradually introduce allergens that you are allergic to under the skin to induce tolerance to those particular allergens. It works in 80-85% cases of pollen allergy and significantly decreases allergy symptoms compared to taking medications alone. It also prevents the fluctuation of symptoms seen during allergy seasons and even prevents you from developing new allergy while taking the shots. Build up phase takes about 3 - 6 months. During this time, you are given increasing amount of allergens to reach an effective dose. Maintenance phase takes 3 to 5 years. It might take up to a year to see a significant change in allergy symptoms. There is a small risk of developing anaphylaxis to allergy shots. That is why you are required to stay in the clinic for at least 20 - 30 minutes after getting the shots.
Allergy shots have been done safely as a cost-effective methods to treat and prevent complications from allergic diseases for over 100 years since it was first introduced by British physician Leonard Noon in 1911.