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.
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
Talk to your doctor about the safety of continuing the allergy shots if you
are pregnant or planning to become
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
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
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Are Allergy Shots 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
dust mites, as well as for allergic asthma. It
is also effective for molds and pet dander. Immunotherapy is not proven to be
effective for hives or
When Should I Call My Doctor?
After receiving your allergy shot, call your doctor and go to the nearest
emergency room if you develop shortness of breath, tight throat, or any other
symptoms of concern.
Beyond Allergy Shots: New Approaches to Immunotherapy
In addition to the traditional allergy shots, several new immunotherapy
procedures have been proposed, including:
- Rush immunotherapy: This approach involves a more rapid, or
rushed, build-up to the maintenance dose of extract. During the initial
phase of treatment, increasing doses of allergen are given every few hours
rather than every few days or weeks. There is a greater risk of a body-wide
reaction with this approach, so rush immunotherapy generally is done in a
hospital under close medical supervision. In some cases, pre-treatment with
medications can reduce the risk of an allergic reaction during rush
- Oral immunotherapy: Oral, or sublingual-swallow, immunotherapy
works in the same way as allergy shots by giving increasing doses of
allergen to gradually build up a person's tolerance. The difference with
oral immunotherapy is the allergen extract is given as drops, usually placed
under the tongue and then swallowed, rather than through injections. This
type of immunotherapy has been shown to be helpful in a select patient
population. However, formulations for sublingual-swallow use are not
available in the United States, nor has sublingual administration received
approval by the U.S. Food and Drug Administration.
- Intranasal immunotherapy: Controlled, well-designed studies have
shown intranasal administration of grass, birch tree, and house dust mite
allergen extracts was effective at reducing nasal symptoms of rhinitis.
Local irritation to the nasal mucosa was the main side effect. However, the
effect of nasal administration may not have the longer lasting benefits that
have been associated with traditional immunotherapy. Currently, intranasal
immunotherapy is not used in the United States.
WebMD Medical Reference
American Academy of Allergy, Asthma and
American College of Allergy, Asthma and Immunology. National
Institutes of Health.
Reviewed by Jonathan L Gelfand, MD
, on February 20, 2010