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Immunotherapy (Allergy Shots Background Information for Patients)

Allergy Shots

Allergen immunotherapy injections or “allergy shots” are prescribed for patient with allergic rhinitis (hay fever), allergic asthma or allergic sensitivities. Immunotherapy is the only medical treatment that could potentially modify allergic disease. Some studies have shown that it may have a preventative role, possibly preventing asthma from developing in some patients with allergic rhinitis. Immunotherapy would be considered for individuals who have moderate or severe symptoms not adequately controlled by environmental control measures and/or medications.


Allergen immunotherapy (allergy shots) may “turn down” allergic reactions to common allergens including pollens, molds, animal dander and dust mites. In most cases, the initial 6 to 12 month course of allergy shots is likely to gradually decrease sensitivity to airborne allergens and continuation of injections lead to further improvement. The injections diminish sensitivities, resulting in fewer symptoms and use of fewer medications. It is important to maintain shots at the proper time interval; missing your shots for a short time may be acceptable but an appropriate adjustment in the dose of the vaccine may be necessary for long lapses in injections. Please see us if you miss receiving you injections for longer than what is recommended for your current vial.

How long are the shots given?

There are generally two phases to immunotherapy; a build-up phase and a maintenance phase:

  • Build up phase: involves receiving injections with increasing amounts of the allergens. The frequency of injections during this phase generally ranges from 3 to 4 times a week, though more rapid build up schedules are sometimes used. This duration is up to 6 months.
  • Maintenance phase: this phrase begins when the effective therapeutic dose is reached. The effective maintenance dose may be individualized for a particular person based on their degree of sensitivity (how ‘allergic they are’ to the allergens in their vaccines) and their response to the immunotherapy build up phase. Once the target dose is reached, the intervals between the allergy injections can be increase. The intervals between maintenance immunotherapy injections generally range from every 1 to every 2 weeks but should be individualized to provide the best combination of effectiveness and safety for each person. Shorter intervals between allergy injections may lead to fewer reactions and a greater benefit in some people and some people may tolerate intervals longer than 4 weeks between injections.

Reactions to allergy injections

It is possible to have an allergic reaction to the allergy injection itself. Reactions can be local (swelling in the injections site) or systemic (affecting the rest of the body). Systemic reactions include hay fever type symptoms, hives, flushing, lightheadedness, and/or asthma, and rarely, life threatening reactions. Some conditions make allergic reactions to the injections more likely: heavy natural exposure to pollen during a pollen season and exercise after an injection. Serious systemic reactions can occur in patients with asthma that has worsened and is not well controlled on recommended medications. Therefore, if you have noted worsening of your asthma symptoms, notify your nurse or physician before receiving your scheduled injections. Reactions to injections can occur, however, even in the absence of these conditions. Please inform the nursing staff if you have been diagnosed with a new medical condition or prescribed any new medications since your last visit. If you have any symptoms occur immediately or within hours of your injection, please inform the nurse before your next injections.


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