What you can expect

By Mayo Clinic Staff

Allergy shots are usually injected in the upper arm.

To be effective, allergy shots are given on a schedule that involves two phases:

  • The buildup phase generally takes three to six months. Typically shots are given one to three times a week. During the buildup phase, the allergen dose is gradually increased with each shot.
  • The maintenance phase generally continues for three to five years or longer. You'll need maintenance shots about once a month.

In some cases the buildup phase is accelerated, which requires several injections of increasing doses during each doctor visit. This can decrease the amount of time you need to reach the maintenance phase and get relief from allergy symptoms, but it also increases your risk of having a severe reaction.

Feb. 22, 2012