Allergy immunotherapy (also known as “desensitization,” “allergy vaccination,” or “hyposensitization”) is the process of administering injections to a pet in order to make them more tolerant of allergens. Common allergens are house dust mites, grass pollens, weed pollens, tree pollens, and fungal spores. Veterinarians have used immunotherapy for over 30 years to treat pets with skin allergies (atopic dermatitis or “AD”). Immunotherapy provides significant relief from itching to most pets with allergies (about 75% respond to treatment). The selection of ingredients is traditionally based on either a blood test or an intradermal test (“skin test”). To perform an intradermal test, pets are sedated or anesthetized and 50-70 different allergens are injected into the skin. A red swelling is interpreted as meaning the pet is possibly allergic to that allergen.