Treatment Overview

When you get immunotherapy in the form of allergy shots,
your
allergist or doctor injects small doses of substances
that you are allergic to (allergens) under your skin. This helps
your body “get used to” the allergen, which can result in fewer or less severe
symptoms of
allergic rhinitis.

Your allergist will
use an extract of grass, weed, or tree pollen;
dust mites; molds; or
animal dander for allergy shots. You must first have
skin testing to find out which allergen you are allergic to.

Your
allergist injects under your skin a solution of salt water (saline) that
contains a very small amount of the allergen(s). At first, you get the shot
once or twice a week. You gradually receive more of the allergen in the shots.

After about 4 to 6 months of weekly shots, you are usually
getting the best amount of allergen in the shot. This is called the maintenance
dose. When you reach the maintenance dose, you get the same dose in shots every
2 to 4 weeks for the next 4 to 6 months.

The period between shots
is gradually increased to about a month. And the dose usually stays the same
each month. After 1 year of maintenance, your allergist will check to see if
you have fewer or less severe symptoms. If your allergy symptoms have not
changed, you will no longer get the shots. If your symptoms have improved, you
may continue to get monthly shots for up to 3 to 5 years.footnote 1

Other ways to get this treatment are called
cluster or
rush immunotherapy, in which you reach the maintenance
dose more quickly.

What To Expect After Treatment

You receive allergy shots in your
allergist’s office. You will stay in the office for 30 minutes after you
get the shots, in case you have a severe reaction (anaphylaxis) to
the injected allergens.

Redness and warmth at the shot site are
common. But these go away after a short period of time.

Why It Is Done

Allergy shots can reduce your
reaction to allergens, which can result in fewer or less severe symptoms. They
may also prevent children who have allergic rhinitis from getting
asthma.footnote 1 Recommendations on when to get allergy shots vary, but in general you and your
doctor may consider them when:

  • Allergy symptoms are severe enough that the
    benefit from the shots outweighs the expense and the time spent getting the
    shots.
  • You are allergic to only a few substances, and they are hard
    to avoid.
  • Avoiding allergens and using medicine do not control
    symptoms, or you have to take medicine all the time to control
    symptoms.
  • Side effects of medicines are a problem.
  • You
    want a treatment for the cause of your allergy, rather than treatment for just
    the symptoms.
  • You have another condition that is being affected by
    allergic rhinitis, such as asthma.
  • You want to lower the chance
    that you will develop asthma.

How Well It Works

Allergy shots are effective in
treating allergic rhinitis and
allergic asthma. The shots
reduce symptoms in those allergic to pollens,
animal dander,
dust mites, mold, and cockroaches. Experts do not know how long allergy shots work
after you stop getting the shots. Some people may not have their allergies return. Others may have allergies return within a few years.footnote 1

Although you still need to avoid allergens, you may be able
to use less medicine or stop using medicines.

Risks

Allergy shots almost always
are safe if given correctly. Redness and warmth at the shot site are common.
Overall body reactions, such as
hives, asthma symptoms, and low
blood pressure, are not common. Because of the
possibility of a life-threatening reaction (anaphylaxis),
you get the shots where emergency care is available.

If you or
your child has another condition, such as
asthma, you may be more likely to have a severe
reaction to the shots. You should have your asthma well controlled before you
get allergy shots.

What To Think About

Although expensive, allergy shots
may cost no more than the combined cost of medicine, doctor and emergency room
visits, and missed days of school or work over several years. But you may need
to take regular shots for 3 to 5 years. And it may take a year or more for
symptoms to improve. If the treatment schedule would be hard for you to
follow, you may want to think about other options. During your treatment, you
should see your doctor at least once every 6 to 12 months.

Allergy
shots treat an allergy to just one allergen or a very closely related group of
them, such as grass pollens. If you are allergic to more than one type of
allergen, you may need to receive shots for each type of allergen to relieve
all of your symptoms. The allergens can usually be combined into one or two
shots.

Children younger than 2 should not have allergy shots.
Children ages 3 to 4 may find it hard to get many shots over a long
period of time. Talk with your doctor about whether allergy shots are right for
your child.

Older adults may be taking medicines or have other
medical conditions that may increase the risk of a severe reaction to allergy
shots.

You must report any delayed reaction to an allergy shot.
Late reactions can happen any time within 24 hours after a shot. Reactions may
just affect the injection site (such as a large, red or raised area around the
site) or they may affect your overall body (such as trouble breathing).

Pregnant women who are already taking allergy shots may continue them.
But do not start taking them during pregnancy.

Allergy shots
should not be used when you:

  • Have had a recent
    heart attack,
    unstable angina, or other heart problems or are taking
    beta-blockers.
  • Are unable to communicate
    (can’t tell your doctor about reactions to shots). Most doctors do not give
    allergy shots to children younger than 5.
  • Have an immune system
    disease (such as
    AIDS).

Sublingual immunotherapy may be another way to treat certain pollen allergies. Instead of getting shots, you dissolve a tablet under your tongue daily. Each tablet has a small amount of allergen in it. This treatment, like allergy shots, helps your body “get used to” the allergen, so your body reacts less to it over time. Oral and sublingual immunotherapy is being studied for other types of allergies also.

Complete the special treatment information form (PDF) (What is a PDF document?) to help you understand this treatment.

References

Citations

  1. Joint Task Force on Practice Parameters (2011). Allergen immunotherapy: A practice parameter third update. Journal of Allergy and Clinical Immunology, 127(1, Suppl): S1-S55.

Credits

ByHealthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD – Internal Medicine
Specialist Medical Reviewer Martin J. Gabica, MD – Family Medicine

Current as ofOctober 6, 2017