Allergy Shots

How Do Allergy Shots Work?

Allergy shots help your body fight the allergen. When you get shots of a much smaller dose of the allergen, your body makes antibodies to the allergen. The next time you have contact with the allergen, these antibodies help block its effect. Because the antibodies block the way your body reacts to the allergen, your allergy symptoms become less severe. After many allergy shots, you might start to get relief from your allergy symptoms. This relief will last for a long time.

What Is In the Shot?

In the shot is a low level of allergen (proteins and glycoproteins), which is not enough to elicit an IgE reaction. The dose is slowly increased until eventually the patient can tolerate a significant exposure to the allergen.

Two Phases Allergy Shots

In the build-up phase, patients receive allergen injections of gradually increasing dosages. They receive injections once or twice per week during this phase, until an effective therapeutic dosage is reached. The duration of this phase varies between patients but it generally lasts up to six months.

When a patient is done with the build-up phase and a therapeutic dosage is reached, the maintenance treatment phase begins. Of course the allergen vaccine dosage is different for each patient, as this depends on their sensitivity to each allergen. However, there is now a longer interval between injections, which usually take place every two to four weeks in this interval. The maintenance phase of treatment may last for a period of three to five years, but it is hoped that therapeutic benefit will be seen after twelve months on this phase.

What Will Happen If My Doctor and I
Choose Allergy Shots to Treat My Allergy?

Your doctor will want to do an allergy test to help determine exactly what is causing your allergy. An allergy skin test puts tiny amounts of allergens onto your skin to see which ones you react to. Or your doctor may decide to do a blood test, such as the radioallergosorbent test (called RAST) or the ImmunoCap Test.

Allergy Shot Effectiveness

This allergy treatment is not considered to be an effective treatment for food allergies or allergies to medication. It has been shown to be more effective for environmental allergens that are difficult to avoid, such as cats, seasonal, dust, grass and mold, etc.

Also, allergy shots have been shown to be more effective when the treatment regimen begins early in a patient’Äôs life, or if treatment begins soon after an allergy manifests.

Typically, the course of treatment requires about three to five years of injections administered in 50 to 70 doctor visits. The shots are painful and sometimes cause severe or even dangerous reactions. Perhaps 25 percent of patients will fail to get relief from their allergies, which is pretty annoying after five years of uncomfortable injections and as many as 70 doctor visits.

Can Everyone Get Allergy Shots?

No. Allergy shots may not be good for you if you have severe asthma or heart problems. You shouldn't get allergy shots if you take a beta blocker for heart problems. Children younger than 5 years of age shouldn't get allergy shots.

Side Effects: Pain, redness, and swelling where the allergen vaccine was injected. Conversely, systemic reactions are cause for concern.

Systemic reactions can manifest with allergy shot side effects such as hives, sneezing, or congestion. These reactions can appear in a more serious form known as anaphylaxis. In anaphylaxis, life threatening events can occur such as swelling of the throat and tightness of the chest. These reactions usually occur within thirty minutes of injection and they require immediate treatment by a physician.

Safety of Allergy Shots

Allergy shots are considered to be a safe treatment for allergies, although adverse reactions have been reported in a number of patients. One researcher found that serious reactions due to this treatment occurred in less than one percent of the patients who received treatment.

Because of the risks associated with treatment, patients who have serious health conditions such as heart problems or hypertension are not candidates for immunotherapy. Young children may also not be candidates for this treatment since they could have trouble communicating the fact that they are experiencing an allergic reaction after their injection.

Are Allergy Shots a "Cure"?

Immunotherapy, or allergy shots, is not a cure. Rather, the shots are a way to significantly lessen the symptoms caused by exposure to specific substances.

References

Baines, Emma. Behind the Headlines: A cure for allergies in three years? GP, Sept, 2006, p14.

Bates, Betsy. Is allergy control heading under the tongue? Skin & Allergy News, Feb 2006, p50.

Kwong, Frank & Cook, Bruce. The Complete Allergy Book. Illinois: Sourcebooks Inc., 2002.

Selecting patients for allergen immunotherapy. Journal of Respiratory Diseases, Sept. 2004, p390.

Sublingual Immunotherapy Relieves Allergic Rhinitis. The Clinical Advisor, Feb 2007, p168-169.