How you prepare

Before starting a course of allergy shots, your doctor will use a skin test or blood test to determine that your reactions are caused by an allergy — and which specific allergens cause your signs and symptoms.

During a skin test, a small amount of the suspected allergen is scratched into your skin and the area is then observed for about 15 minutes. Swelling and redness indicate an allergy to the substance.

When you go in for allergy shots, let the nurses or doctors know if you are feeling unwell in any way. This is especially important if you have asthma. Also let them know if you had any symptoms after a previous allergy shot.