Medications are typically first-line treatment because they are usually effective for most symptoms and convenient. Also, allergy testing is not needed. But if medications are not enough, allergy testing will provide the information needed to create an allergen avoidance plan and/or allergy serum for immunotherapy. In reality, most patients have multiple allergies and avoidance has limited effectiveness. However, I typically recommend that patients allergy-proof their bedroom. It is helpful to establish this "safe-zone" where their body can get a rest from exposure to allergens.
Immunotherapy used to be considered a "last-line" therapy because of the inconvenience and potentially serious adverse reactions. However, with the advent of sublingual immunotherapy (aka SLIT or allergy drops), both of these problems have been addressed. Allergy drops are placed under the tongue at home, without shots. There have been no serious adverse reactions in over 60 years of use in Europe. While they are not yet approved by the US FDA, they have been approved by the World Health Organization since 1996 and recently passed an FDA safety trial as a first step toward approval. Still, allergy drops are already widely used in the United States, using the same FDA-approved serum typically used for shots as an "off-label" use. Using medications as an "off label" use is common practice for many medications as the FDA does not test every medications for every use. In my practice, we have several hundred patients using allergy drops with excellent results and no serious side effects. Thus it is likely that over time, immunotherapy will become a more common first-line allergy treatment over medications which themselves can have significant side effects.