Subcutaneous Immunotherapy

Allergy shots - Frequently asked questions

What are Allergy Shots?

Allergen immunotherapy injections or "allergy shots" are prescribed for patients with allergic rhinoconjunctivitis (hay fever), allergic asthma, or life threatening reactions to insect stings. They work by gradually increasing the amount of allergen that a patient is exposed to, over an extended period of time. Immunotherapy is the only medical treatment that has the potential to modify allergic disease and make an individual less allergic. Some studies have shown that it may have a preventive role in allergic children, preventing asthma from developing in some patients with allergic rhinitis, and improving eczema control as well.  Immunotherapy is considered for individuals who have moderate or severe symptoms not adequately controlled by environmental control measures and/or medications, or for patients who prefer to control their symptoms without the use of daily medication.

How are shots given?

There are 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 1 to 2 times a week, though more rapid build-up schedules are sometimes used. The duration of this phase depends on the frequency of the injections, but generally ranges from 4 to 8 months (at a frequency of 2 times and 1 time a week, respectively).

• Maintenance phase: This phase begins when the effective therapeutic dose is reached. The effective therapeutic dose is based on recommendations from a national collaborative committee called the Joint Task Force for Practice Parameters: Allergen Immunotherapy: A Practice Parameter, and was determined after review of multiple published studies on immunotherapy.  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 vaccine) and their response to the immunotherapy build-up phase. 

How Often and for How Long are Allergy Shots Needed, Long-Term?

Once the target maintenance dose is reached, the intervals between the allergy injections can be increased.  The interval between maintenance immunotherapy injections generally ranges from every 2 to every 4 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 greater benefit in some people and some individuals may tolerate intervals longer than four weeks between injections. In order to receive the full benefit from allergy shots, it is advisable to continue maintenance doses of immunotherapy for ~5 years, regardless of the frequency of injections. For most patients, allergy shots can then be discontinued, but the patient will continue to receive benefit for up to another 10 years. Some patients may find that their symptoms remain better controlled when maintenance shots are continued for a longer duration, either due to the baseline severity of their allergies or due to unavoidable daily allergen exposure. 

Can I Develop a Reaction from Allergy Injections?

It is possible to have an allergic reaction to the allergy injection itself. Reactions can be local (swelling at the injection 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 can make allergic reactions to the injections more likely, such as 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 allergy technician, nurse, or clinician before receiving your scheduled injections! Reactions to injections can occur, however, even in the absence of these conditions. The risk of local and systemic reactions is significantly decreased by taking a long-acting antihistamine at least 30 min - 4 hours before receiving immunotherapy, depending on the medication taken. You will be asked to take an antihistamine and return at a later time if you have forgotten to take your medication in advance.

Please inform the clinic staff if you have been diagnosed with a new medical condition or prescribed any new medications since your last visit. If any symptoms occur immediately or within hours of your injection, please inform us before you receive your next injection. 

We hope this information helps answer some of your questions about allergen immunotherapy. If you have any other questions, please do not hesitate to ask us. Our primary goal is your health and safety.

Updated: 02/28/2023