As a preventative treatment, immunotherapy is effective against allergic reactions caused by allergens such as grass pollen, house dust mites, bee venom, and more. When a person is allergic to a substance, or allergen, immunotherapy involves exposing them to gradually increasing doses of that substance.  Gradually increasing exposure to the allergen results in the immune system’s sensitivity to the substance declining due to a decrease in the production of the offending antibodies. Additionally, immunotherapy reduces the inflammation associated with rhinitis and asthma. A patient and allergist identify trigger factors for allergy symptoms before treatment begins. It is sometimes possible to confirm the specific allergens to which a person has antibodies through skin or blood tests. A person with selective hypersensitivity to multiple allergens usually needs immunotherapy.