Allergy shots are in the news a lot recently, mainly due to sub-lingual immunotherapy undergoing FDA approval. For now I would like to review subcutaneous immunotherapy, which has been around for 100 years. This information is adapted from the American Academy of Asthma, Allergy and Immunology.
If you suffer from allergy symptoms, you may wonder if allergy immunotherapy (allergy shots) is the best treatment for you. While it requires time and patience, the payback can be long-term relief.
Allergy immunotherapy is the medical term for allergy shots prescribed by allergists. An allergist/immunologist, often referred to as an allergist, has specialized training and experience to determine which allergens are causing your symptoms and discuss if allergy immunotherapy is right for you. Occasionally doctors give cortisone-type shots that can temporarily reduce allergy symptoms. These types of shots are different and should not be confused with allergy immunotherapy injections.
How Does Allergy Immunotherapy (Allergy Shots) Work?
Allergy immunotherapy works much like a vaccine. Your body responds to injected amounts of a particular allergen given in increasing doses, eventually developing a resistance and tolerance to it. Allergy shots can lead to decreased, minimal or no allergy symptoms.
There generally are two phases to allergy immunotherapy: build-up and maintenance. Build-up often ranges from three to six months and involves receiving injections with increasing amounts of the allergens. The shots are typically given once or twice a week, though more rapid build-up schedules are sometimes used.
The maintenance phase begins when the most effective dose is reached. This dose is different for each person, depending on how allergic you are and your response to the build-up phase. Once the maintenance dose is reached, there are longer periods between injections, typically two to four weeks.
When Will I Feel Better?
Some may experience decreased allergy symptoms during the build-up phase. For others, it may take as long as 12 months on the maintenance dose. If there is no improvement after a year of maintenance, your allergist will discuss other treatment options with you.
If you aren’t responding to allergy immunotherapy, it may be because there is not enough dose of the allergen in your vaccine or there are missing allergens that were not identified during your allergy testing. Other reasons could be that there are high levels of the allergen in your environment or major exposure to non-allergic triggers like tobacco smoke.
What Is the Length of Treatment?
Once the maintenance dose is reached, allergy immunotherapy is generally continued for three to five years. The decision to stop should be discussed with your allergist at that time. Some people may experience a permanent reduction of allergy symptoms. Others may relapse and a longer course of allergy shots can be considered.
Allergy immunotherapy for children age five and older is effective and often well tolerated. It might prevent the onset of new allergen sensitivities or the progression to asthma. Allergy immunotherapy is not started on patients who are pregnant but can be continued on patients who become pregnant while receiving it. In some patients with other medical conditions or who take certain common medications, allergy shots may be more risky. It is important to mention other medications you take to your allergist.
What Are the Possible Reactions?
The two types of adverse reactions that can occur with allergy shots are local and systemic. Common local reactions include very mild redness and swelling at the injection site, which can happen immediately or several hours after. A systemic reaction, which is less common, affects the entire body or a particular body system. They are usually mild and typically respond quickly to medications. Signs include increased allergy symptoms such as sneezing, a stuffy nose or hives.
Rarely, a serious systemic reaction called anaphylaxis (pronounced an-a-fi-LAK-sis) can develop. Symptoms include swelling in the throat, wheezing, a feeling of tightness in the chest, nausea or dizziness. Most serious systemic reactions develop within 30 minutes of allergy injections. This is why it is strongly recommended you wait in your doctor’s office for 30 minutes after your injections. Your allergist is trained to watch for reactions, and his or her staff is trained and equipped with the proper medications to identify and treat them.