Allergy Shots: What to Know

Allergy shots help your body get used to allergens, the things that trigger an allergic reaction. They aren’t a cure, but in time, your symptoms will get better and you may not have symptoms as often.

You may want to consider allergy shots -- also called " immunotherapy" -- if you have symptoms more than 3 months a year and medicines don’t give you enough relief.

How Often Do You Get Allergy Shots?

At first, you’ll go to your doctor once or twice a week for several months. You’ll get the shot in your upper arm. It'll contain a tiny amount of the thing you’re allergic to -- pollen, pet dander, mold, dust mites, or bee venom, for example.

The dose will go up gradually until you get to what’s called a maintenance dose. After that, you’ll usually get a shot every 2-4 weeks for 4-5 months. Then your doctor will gradually increase the time between shots until you’re getting them about once a month for 3-5 years. During that time, your allergy symptoms will get better and may even go away.

If your symptoms don’t improve after a year of shots, talk with your doctor about other treatment options.

How Should I Prepare for Allergy Shots?

You may want to avoid exercise or doing anything strenuous for 2 hours before and after your appointment. That’s because exercise boosts blood flow to the tissues and may cause the allergens to spread throughout your body faster. It’s not likely to cause a serious problem, but it’s best to be safe.

Tell your doctor about any other medicines or herbs and supplements you take. Some medications interfere with the treatment or raise the risk of side effects. You may need to stop allergy shots if you take these medications.

If you’re pregnant or planning to get pregnant, ask your doctor whether you should continue to get allergy shots.

What Should I Expect Afteward?

Usually, you’ll stay at the doctor’s office for about 30 minutes after you get an allergy shot. That's to make sure you don't get side effects like itchy eyes, shortness of breath, a runny nose, or a tight throat. If you get these symptoms after you leave, go back to your doctor's office or to the nearest emergency room.

Redness, swelling, or irritation right around the site of the injection is normal. These symptoms should go away in 4 to 8 hours.

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Do Allergy Shots Work for Everyone?

A lot depends on how many things you're allergic to and how severe your symptoms are. Generally, allergy shots work for allergies to bee stings, pollen, dust mites, mold, and pet dander. There’s no proof that they work for food, drug, or latex allergies.

When Should I Call My Doctor?

Get on the phone and go to the nearest emergency room if you have shortness of breath, a tight throat, or any other symptoms that worry you after getting your shot.

Do I Have to Get a Shot?

There is another type of immunotherapy: three under-the-tongue tablets that you can take at home. Called Grastek, Oralair, and Ragwitek, they treat hay fever and boost your tolerance of allergy triggers.

What Is Rush Immunotherapy?

It’s a faster way to get to a maintenance dose, but it’s also riskier.

During the first part of the treatment, you get doses of the allergen every day instead of every few days. Your doctor will check on you closely, in case you have a bad reaction. In some cases, you may get medicine before you get the dose of the allergen, to help prevent a reaction.

Who Should Not Get Allergy Shots?

They may be more risky for people with heart or lung disease, or who take certain medications. Tell your allergist about your health and any medicines you take, so you can decide if allergy shots are right for you.

WebMD Medical Reference Reviewed by Jennifer Robinson, MD on October 12, 2016

Sources

SOURCES:

American Academy of Allergy, Asthma and Immunology.

American College of Allergy, Asthma and Immunology.

National Institutes of Health.

The John Hopkins Sinus Center: "Sublingual Immunotherapy."

UpToDate: "Oral and sublingual immunotherapy for allergic rhinitis."

News release, FDA.

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