Allergy symptoms won't stop overnight. They usually improve during the first year of treatment, but the most noticeable improvement often happens during the second year. By the third year, most people are desensitized to the allergens contained in the shots — and no longer have significant allergic reactions to those substances.

After a few years of successful treatment, some people don't have these significant allergy problems even after allergy shots are stopped. Other people need ongoing shots to keep symptoms under control.

Feb. 22, 2012