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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 allergies more than 3 months each year.
They do not cure allergies, but reduce your sensitivity
to certain substances.
How
Often Are the Shots Given?
Allergy
shots are given regularly (in the upper arm), with gradually
increasing doses. When starting immunotherapy, you should
go to your healthcare provider no less than every 8
days for about 40 weeks. 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 4 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 the 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 if you are taking a beta-blocker or monoamine
oxidase inhibitor (MAOI) medication. These medications
can interfere with the treatment needed if you have
an allergic reaction after receiving the allergy shot.
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 the Shots?
Usually,
you will be monitored for about 30 minutes after receiving
the 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.
Is
Immunotherapy 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 less effective for molds
and pet dander, and is not proven to be effective for
hives or food allergies.
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.
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 immunotherapy.
Oral immunotherapy: Oral 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.
Convenience is another benefit of oral immunotherapy
because people can take the drops themselves at home.
In Europe, where it is more widely used, oral immunotherapy
has been successful in treating many types of severe
allergies, including those caused by dust mites, pollens,
molds, and pets. However, relatively few allergists
in the U.S. currently offer oral immunotherapy, as the
extracts are not standardized. In addition, the FDA
has not approved any oral extract.
Enzyme potentiated desensitization (EPD): Enzyme potentiated
desensitization, also called low-dose immunotherapy,
uses very small doses of allergen along with an enzyme
called b-glucuronidase. Proponents of this treatment
claim that EPD can be used to treat a broad range of
allergens without the need for weekly shots. This includes
allergies to foods, which generally are not successfully
treated with traditional allergy shots. This approach
is still considered experimental.
Reviewed
by the doctors at The Cleveland Clinic Department of
Pulmonary, Allergy and Critical Care Medicine.
Edited
by Charlotte E. Grayson, MD, Feb. 2004, WebMD.
Portions
of this page © The Cleveland Clinic 2000-2004
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