Author: V. Dimov, M.D., Allergist/Immunologist, Cleveland Clinic
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU
Allergen immunotherapy ("allergy shots") has been used for more than 120 years. It has a long track record of being very effective and safe when done by an allergist specialist. Allergy shots treat the underlying cause of allergies, not just the symptoms (Allergy, 2012).
If you have allergies, you may be wondering if allergy shots are the best treatment for you. Here are the answers to some commonly asked questions.
Frequently asked questions
1. What exactly is in the allergy shots?
Allergy shots have allergen extracts in them. Extracts are made from natural substances that cause allergies including pollen, dust mites, animal allergens, and molds. The extracts are licensed by the U.S. Food and Drug Administration (FDA).
2. How do allergy shots work?
Allergy skin testing will detect the allergens you may react to. Extracts (small amounts of the allergens) trigger a skin reaction during the skin test. The same extracts are used for allergy shots. This is one of the reasons the allergy shots work so well - you get treated with exactly what you are allergic to. The doses are gradually increased so that the body builds up immunity to these allergens. Allergy shots work similar to a preventive vaccine.
3. How often do I need to get allergy shots?
There are two stages of the allergy shots (immunotherapy), build-up and maintenance:
- Build-up stage usually takes between 3 and 6 months. Build-up is with allergy shots with increasing amounts of the allergens. If you get your injections once a week, build-up takes around 6 months. If you get your injections 2-3 times per week, the build-up stage may take as quickly as 3 months. Build-up stage is the most difficult part of the allergy shots as it takes frequent visits (once to twice per week).
- Maintenance stage begins when you reach the full dose of allergy shots (maintenance dose). You typically receive the the full dose allergy shots once a month (every 4 weeks). Maintenance typically continues for 36 doses, or approximately 3 years.
4. How effective are allergy shots?
According to the National Institute of Allergy and Infectious Diseases (NIAID), about 80-90% of people with allergic rhinitis will see their symptoms and need for medication use drop significantly within a year of starting allergy shots.
5. How quickly will I feel better?
Many patients feel better during the build-up phase of allergy shots, within 3-6 months. For others, it may take as long as 12 months of the maintenance dose.
6. How long should I stay on allergy shots?
Once the maintenance dose is reached (it takes 3-6 months), allergy shots are continued for at least 3 years. Based on the response, the allergy shots are safe to continue longer than 3 years. The decision to stop should be discussed with your allergist. Some people may have a permanent reduction of their allergy symptoms (the best outcome). Others may relapse and then a longer course of allergy shots can be considered.
7. What are the risks of allergy shots?
There are two types of adverse reactions that can occur with allergy shots:
- A local reaction is common but not dangerous. The local reaction is usually mild redness and swelling at the site of the allergy shots. This can happen immediately, or several hours after the shot.
- A systemic reaction is not common but it could be dangerous. Systematic reactions are usually mild and respond quickly to medications. Signs of a systemic reaction include increased allergy symptoms such as sneezing, stuffy nose or hives. Rarely, a serious systemic reaction called anaphylaxis (an-a-fi-LAK-sis) can develop, with swelling in the throat, wheezing, a feeling of tightness in the chest, nausea or dizziness. This requires treatment with epinephrine (EpiPen).
Most systemic reactions develop within 30 minutes of receiving allergy shots. You should you wait in your allergist office for 30 minutes after your injections.
8. Who gives you the allergy shots?
An allergist is the most qualified physician to test which allergy you have and tell you if allergy shots are right for you. The safest approach is to be seen and treated by a board-certified allergist. You can find an allergist here: http://www.acaai.org/allergist/Pages/locate_an_allergist.aspx
Allergy shots should always be given under the observation of a trained physician.
8. Who needs allergy shots?
Children or adults who don't respond to either over-the-counter (OTC) or prescription medications, or who suffer from frequent complications of allergic rhinitis, may be candidates for allergy shots.
Allergy shots are recommended for patients with allergic asthma, allergic rhinitis/conjunctivitis and stinging insect allergy. They are not recommended for food allergies.
Before a decision is made to begin allergy shots, the following issues must be considered:
- Length of allergy season and the severity of your symptoms
- Whether medications and/or changes to your environment can control your allergy symptoms
- Your desire to avoid long-term medication use
- Time: allergy shots require a major time commitment. The duration is typically 3-5 years, and the shots often require brief clinic visits every 2-4 weeks.
- Cost: may vary depending on your state and insurance coverage
Immunotherapy for children is effective and well tolerated. It prevents the onset of new allergies. Allergy shots are the only treatment that prevents the progression from allergic rhinitis to asthma.
9. Is there an alternative to allergy shots such as tablet, drops, etc.?
Yes, there are FDA-approved tablets with ragweed pollen, grass pollen, and dust mite. They have a black box warning about dangerous allergic reactions and require an epinephrine prescription.
10. Can you treat food allergy with allergy shots?
Allergy shots are never appropriate for food allergies. However, it is common to use extracts to test for food allergies.
Allergy Immunotherapy, Allergy Shots. ACAAI.
Allergy Relief for Your Child - FDA Consumer Info.
Allergy Shots: Tips to Remember. AAAAI.
Allergen-specific immunotherapy. Allergy, Asthma & Clinical Immunology 2011, 7(Suppl 1):S5.
Allergy immunotherapy: Reduced health care costs in adults and children with allergic rhinitis. http://buff.ly/12sDYdh
Image source: Pollen from a variety of common plants. Dartmouth Electron Microscope Facility, Dartmouth College.