Allergy shots (allergy immunotherapy)

Allergy shots (allergy immunotherapy) are a form of long-term allergy treatment. Allergy shots work by getting your immune system “used to” the specific particles (allergens) that trigger a reaction. Each allergy shot contains a tiny amount of allergens – just enough to cause an immune response, but not enough to cause a full-blown reaction.

Your doctor gradually increases the dose of allergen with each shot, desensitizing your immune system to the allergen. Allergy shots don’t cure allergies, but they can make symptoms less severe. The effect usually lasts even after you have stopped the treatment.

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Are allergy shots effective?

When the treatment is done correctly, allergy shots can be as much as 90% effective at reducing symptoms. They can also prevent the development of new allergies or prevent diseases like asthma from getting worse.

However, not everyone should get allergy shots. Allergy shots are usually only recommended when:

  • Medication can’t control your symptoms and you cannot avoid the allergen.
  • Allergy medications interact with other medications you take, causing side effects or reducing the effectiveness of either medication.
  • You want to reduce your long-term use of allergy medications.

Allergy shots are not recommended if:

  • You are trying to treat a food allergy, latex allergy or medication allergy. Allergy shots are not effective against these types of allergies. It is best to avoid these substances altogether.
  • Your child is under 5 years of age: Allergy shots are not recommended for children under 5 because these children may find it challenging to cooperate with the program or express that they are having a negative reaction.
  • You have a heart condition or cardiac disease.
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When deciding if allergy shots are right for you, you and your allergist should also consider:

  • The length of allergy season and the severity of your symptoms.
  • Your current medications.
  • Your time availability (allergy shot treatment can take several months or years to be effective).
  • The cost of the treatment and your insurance coverage.
  • Whether other options, like oral pills, are better suited to your situation.

What to expect during allergy shot treatment

Before starting your allergy shot treatment, you and your provider will discuss whether you are a good candidate for the treatment and what you can expect. You should tell your provider about any medications, herbs or supplements you take. Your provider will also do a skin test or blood test to determine what allergens are causing your reaction. These tests will inform your treatment plan.

How you prepare

Do not exercise two hours before your appointment. When you arrive for your appointment, be sure to tell the nurse or doctor if you are feeling unwell or if you had any symptoms after your last allergy shot. This is especially important if you have asthma. If you are pregnant or think you may be pregnant, talk to your doctor about whether you should continue with the allergy shots.

During your appointment

Your provider will give you an injection in your upper arm. You will then need to stay at the facility for 30 minutes to make sure you don’t have a severe reaction. After, you will be able to go about your day as normal.

Possible side effects

For most people, the only side effect of an allergy shot is redness and swelling at the injection site. However, you may also experience:

  • A rash or hives
  • Congestion
  • Itchy eyes
  • Runny nose
  • Sneezing

These symptoms should be temporary and go away within 8 hours of the injection.  

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Allergy shots: treatment phases

There are two phases of treatment:

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  • Build-up phase: You will receive allergy shots once or twice a week. The dose of allergens will gradually increase. This phase lasts 3-6 months, depending on the severity of your allergy and how often you receive injections.
  • Maintenance phase: After the build-up phase, you will receive injections once a month for anywhere from 3-5 years. This ensures that your immune system remains desensitized to the allergen.

What does an allergy shots treatment cost?

Many insurance companies cover part or all of the costs associated with allergy shots. Medicaid and Medicare part B generally cover the cost of allergy shots if they are deemed medically necessary. It is worth checking with your insurance company to see if you are eligible.

Without insurance, the cost of allergy shots can vary widely. You should talk to your provider about the benefits and costs.

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References

American Academy of Allergy Asthma & Immunology (AAAAI). Allergy Shots (Immunotherapy) – https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/allergy-shots-(immunotherapy)

MedlinePlus: National Library of Medicine. Allergy shots – https://medlineplus.gov/ency/patientinstructions/000405.htm

National Center for Biotechnology Information (NCBI): National Library of Medicine. Allergy Immunotherapy – https://www.ncbi.nlm.nih.gov/books/NBK535367/