Immunotherapy is like a vaccination against your allergies. Vaccines shots are to prevent infections; immunotherapy shots are to prevent allergies. However, the two work in opposite ways. Vaccinations prime the immune system to help the body react swiftly if the disease is encountered again, whereas immunotherapy dulls the reaction to allergens.

In the long term, allergy shots can minimize the need for antihistamines or other allergy medications. Immunotherapy builds up your tolerance to specific allergens, so your body won't overreact to them.

Immunotherapy shots are used for most airborne allergens, including tree, grass, and weed pollens, mold spores, dust mites, and animal allergens. Immunotherapy shots can also be used to prevent severe sting reactions from honeybees, yellow jackets, hornets, wasps, or fire ants.

How does it work?

Your allergist will first confirm what you're allergic to with allergy testing. Next, he or she will inject small amounts of allergens over the course of many months, periodically increasing the amount of allergens injected. After receiving each shot, you will need to stay in the doctor's office for 20-30 minutes to see if you react adversely. Also, your allergist will ask you how you felt after getting the previous shot.

The injection schedule depends on the individual. Generally, 1-2 shots are given weekly in the beginning during the "dose building" stage. They eventually taper off to monthly "maintenance" shots. For some people, it may take up to 12 months to reach the maintenance dose.

Immunotherapy treatment can last for 3-5 years, but you may start feeling relief from symptoms within 6-12 months of starting the therapy. After stopping immunotherapy, the benefits can last for more than 3 years.

If you are considering immunotherapy and have not visited an allergist, ask your primary care physician for a referral. Also, if you have health insurance, find out if immunotherapy is covered.

Who can benefit?

With the advice of your allergist, you can decide if immunotherapy is right for you. Do the benefits of immunotherapy outweigh the time commitment, risks, and costs involved? Consider immunotherapy if:

• You do not like the side effects of allergy medication.
• Allergy medications have not been effective.
• You need multiple allergy medications.
• You cannot avoid the allergen in your environment.
• You experience allergy symptoms year-round.
• Your allergy symptoms interfere with your daily life (e.g., lack of sleep, missing work or school).

Immunotherapy has proven to be effective at reducing symptoms of:

• Allergic rhinitis
• Allergic conjunctivitis
• Asthma
• Stinging insect allergy

Risks involved with immunotherapy

Since immunotherapy involves the injection of something that you are allergic to, there is a small risk of anaphylaxis for some people. Immunotherapy must be performed in a medical setting, where epinephrine and other emergency allergy treatments are easily accessible -- this minimizes the risk of anaphylactic shock.

You should also not receive immunotherapy if you have:

• Acute or chronic lung disorders
• Uncontrolled asthma
• History of heart attack or other heart problems
• Uncontrolled hypertension
• Kidney failure