Allergy shots help your body get used to allergens, the things that trigger an allergic reaction. They don’t cure allergies, but eventually your symptoms will get better and you may not have allergic reactions as often. Allergy shots, also called "immunotherapy," may work for you if allergy medicines don’t work well for you or you have symptoms more than three months a year.
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 will 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 haven't improved after a year of shots, your doctor will talk to you about other treatment options.
How Should I Prepare for Allergy Shots?
You may want to avoid exercise or doing anything strenuous for two hours before and after your appointment. That’s because exercise may increase blood flow to the tissues and cause the allergens to get into your blood 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 are taking. Some medications interfere with the treatment or increase your risk of side effects. You may need to stop allergy shots if you are taking 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 After Allergy Shots?
Usually, you’ll stay at the doctor’s office for about 30 minutes after receiving an allergy shot to make sure that you don't develop side effects like itchy eyes, shortness of breath, runny nose, or tight throat. If you get these symptoms after you leave, go back to your doctor's office or go 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.
Do Allergy Shots Work for All Allergies?
A lot depends on how many things you are 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.