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Allergy shots, also called "immunotherapy," are given to increase your tolerance to the substances (allergens) that provoke allergy symptoms. They usually are recommended for people who suffer from severe allergies or for those who have allergy symptoms more than 3 months each year. They do not cure allergies, but reduce your sensitivity to certain substances.

Air Pollution and Allergies: A Connection?

Medical Author: Alan Szeftel, MD, FCCP
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Does the "air we breathe" have an impact on the rising incidence of allergies and asthma? Hay fever was rare in Japan before World War II. However, pollen allergy is now common and mostly affects those living in Japanese cities and near highways. Allergic disease is also more common in highly developed countries in North America and Europe and less common in Third World countries. This suggests that there must be something about modern, urban life that promotes allergy. Let us examine the impact of air pollution.

By far the most important indoor pollutant is tobacco smoke, which is strongly associated with allergic sensitization, asthma, and other respiratory illnesses. Exposure to smoke results in the body's enhanced ability to produce IgE(the allergy antibody) that attaches to allergens (e.g. pollen, dust mites and dander). The IgE response is a key trigger of allergic reactions. Parental smoking increases the risk of their children having many respiratory illnesses, including bronchitis, chronic cough, and asthma.

Learn more about potential causes of allergies »

How Often Are Allergy Shots Given?

Allergy shots are given regularly (in the upper arm), with gradually increasing doses. When starting immunotherapy, you will need to go to your healthcare provider once or twice a week for several months. The dose is increased each time until the maintenance dose is reached. If the shots are effective, you will go to your healthcare provider every 2 to 4 weeks for 2 to 5 more years. You may become less sensitive to allergens during this time, and your allergy symptoms will become milder and may even go away completely.

How Should I Prepare for Allergy Shots?

For two hours before and after your appointment, do not exercise or engage in vigorous activity. Exercise may stimulate increased blood flow to the tissues and promote faster release of antigens into the bloodstream.

Tell your doctor about all the medications you are taking. Some medications, such as beta blockers, can interfere with the treatment and/or increase the risk of side effects. You may have to stop allergy shots if you are taking these medications.

Talk to your doctor about the safety of continuing the allergy shots if you are pregnant or planning to become pregnant.

What Should I Expect After Allergy Shots?

Usually, you will be monitored for about 30 minutes after receiving an allergy shot to make sure that you don't develop side effects such as itchy eyes, shortness of breath, runny nose, or tight throat. If you develop these symptoms after you leave the doctor's office, take an antihistamine and go back to your doctor's office or go to the nearest emergency room.

Redness, swelling, or irritation within one inch of the site of the injection is normal. These symptoms should go away within 4 to 8 hours after receiving the shot.