Allergy injections and immunotherapy

Allergy injections, also called "immunotherapy", are given to increase your tolerance to the substances (allergens) that provoke allergy symptoms. Usually, they are recommended for people who suffer from severe allergy symptoms despite appropriate allergy treatment. They do not cure allergies but reduce sensitivity to certain substances.

How often are allergy injections given?

Allergy injections are given regularly (in the upper arm), in gradually increasing doses. To start with, 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 jabs are effective, you will continue to go to your healthcare provider every two to four weeks for two to five more years. You may become less sensitive to allergens during this time, and your allergy symptoms will become milder. They may even disappear completely.

How should I prepare for allergy injections?

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

If you are pregnant or planning to become pregnant you should talk to your doctor about the safety of continuing the allergy injections.

What should I expect after allergy injections?

Usually, you will be monitored for about 30 minutes after receiving an allergy injection 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 clinic, take an antihistamine and go back to your doctor's clinic or go to the nearest accident and emergency department.

Redness, swelling or irritation within one inch of the site of the injection is normal. These symptoms should go away within four to eight hours of receiving the injection.

Are allergy injections effective for all allergies?

The effectiveness of immunotherapy varies depending on the severity of a person’s allergies and the number of substances to which the person is allergic. In general, however, immunotherapy is effective for allergies to stinging insects, a variety of pollens and house dust mites, as well as for allergic asthma. It is also effective for moulds and pet dander. Immunotherapy is not proven to be effective for hives or food allergies.

When should I seek medical advice?

After receiving your allergy injection, seek urgent medical advice and go to the nearest A&E if you develop shortness of breath, tight throat, or any other symptoms of concern.