Allergy Shots

Allergies are the result of a chain reaction that starts in the immune system. Your immune system controls how your body defends itself. For instance, if you have an allergy to pollen, your immune system identifies pollen as an invader or allergen. Your immune system overreacts by producing antibodies called Immunoglobulin E (IgE). These antibodies travel to cells that release chemicals, causing an allergic reaction.

If you suffer from allergy symptoms, you may wonder if allergy immunotherapy (allergy shots or allergy tablets) is the best treatment for you. The concept behind allergy immunotherapy, whether it is received in the form of shots or tablets, is that the immune system can be desensitized to specific allergens that trigger allergy symptoms. Although it requires time and patience, the payback can be long-term relief.

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—and which form—is right for you. Keep reading for more information on allergy immunotherapy shots. The AAAAI also has information on allergy immunotherapy tablets.

How Do Allergy Shots Work?
Allergy shots work 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: 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 injections. Once the maintenance dose is reached, there are longer periods between injections, typically two to four weeks.

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 shots.

Who Can Be Treated with Allergy Shots?
Allergy shots may be a good treatment approach for people with allergic rhinitis (hay fever), allergic asthma, conjunctivitis (eye allergy) or stinging insect allergy. Allergy shots are not recommended for food allergies.

Before deciding to begin allergy shots, you should consider:

• The length of allergy season and the severity of your symptoms
• Whether medications and/or changes to your environment can control your symptoms
• Your desire to avoid long-term medication use
• Time: allergy immunotherapy requires a major time commitment
• Cost: may vary depending on your region and insurance coverage

Allergy shots for children age five and older are effective and often well tolerated. They might prevent the onset of new allergen sensitivities or the progression to asthma.

Allergy shots are not started on patients who are pregnant but can be continued on patients who become pregnant while receiving them. In some patients with other medical conditions or who take certain common medications, allergy shots may be of risk. It is important to mention other medications you talk to your allergist.  

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 shots, 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 shots are 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.

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 shots. 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.

Who Should Administer Allergy Shots?
The preferred location for receiving shots is your prescribing allergist’s office. Injections can sometimes be given at another facility where the physician and staff are trained to recognize and treat reactions, and have received instructions by your prescribing allergist.

Healthy Tips
• Allergy immunotherapy, whether in the form of shots or tablets, works by building your tolerance to substances that trigger your allergy symptoms.
• Allergy shots have been proven effective for treating allergic rhinitis, conjunctivitis, allergic asthma and stinging insect allergy. Ask your allergist if you could benefit from the treatment.
• Most adverse reactions to allergy shots are mild, but because serious reactions can occur it is safest to have the shots given in an allergist’s office.

Feel Better. Live Better.
An allergist / immunologist, often referred to as an allergist, is a pediatrician or internist with at least two additional years of specialized training in the diagnosis and treatment of allergies, asthma, immune deficiencies and other immunologic diseases.

By visiting the office of an allergist, you can expect an accurate diagnosis, a treatment plan that works and educational information to help you manage your disease and feel better.


Find out more about allergies.

This article has been reviewed by Thanai Pongdee, MD, FAAAAI
