Allergen immunotherapy is a form of treatment aimed at decreasing your sensitivity to substances called allergens. There are two types of allergy immunotherapy available: sublingual drops, which can be administered at home, and traditional allergy injections, administered in your doctors’ office. Allergen immunotherapy involves increasing, over time, the amounts of an allergen to which the patient is allergic to. Immunotherapy has been shown to prevent the development of new allergies and, in children, prevent the progression of an allergic disease from allergic rhinitis to asthma. Allergen immunotherapy can lead to the long lasting relief of allergy symptoms after treatment has stopped.