Patient education: Allergy shots (The Basics)

What are allergy shots? — Allergy shots are a treatment that can make you less likely to have allergy symptoms. They are also called "allergen immunotherapy." That's because the shots change the way your immune system reacts to allergens. Allergens are the things you are allergic to.

Allergy shots are usually made to order, just for you. They contain tiny amounts of allergens, such as pollen or mold. If you are allergic to stings from bees or other insects, allergy shots can lower your chances of having a dangerous reaction to a sting in the future.

Allergy shots work for allergies to:

●Pollen from trees, weeds, and grasses

●Mold spores in the outside air

●Cat or dog "dander" (tiny flakes of fur, hair, and skin)

●Dust mites (tiny insects found in dust)

●Stings from honeybees, yellow jackets, hornets, wasps, and (in some areas) fire ants

Allergy shots are not used to treat allergies to food, latex, or medicines.

Why do I need allergy shots? — If you have allergies, you should avoid pollen, molds, and other things that make you have allergic reactions. You can also take allergy medicines. But if those treatments don't work well enough, your doctor might recommend allergy shots. Also, in children with nasal allergies, allergy shots can help prevent asthma later in life.

Your doctor will also recommend allergy shots if you had a serious allergic reaction to a sting from a bee or other insect. Symptoms of a serious allergic reaction, called "anaphylaxis," include:

●Flushing – This is when your skin turns red and feels hot (especially on your face).

●Hives – These are raised patches of skin that are very itchy (picture 1).

●Angioedema – This is swelling of the face, eyelids, mouth, tongue, hands, and feet (picture 2).

●Trouble breathing, wheezing, or a change in voice

●Vomiting or diarrhea

●Feeling dizzy or passing out

Allergy shots for insect stings will make you much less likely to get anaphylaxis if you are stung in the future.

Are allergy shots safe for everyone? — Allergy shots can be safe for people of all ages. If you get pregnant while getting allergy shots, you can keep getting the shots. But pregnant people should wait until after giving birth to start allergy shots.

Some medicines, such as beta blockers, can cause problems in people getting allergy shots. Make sure that your doctor knows all of the medicines you take before starting allergy shots. In some cases, you might need to change your medicines to get allergy shots.

What happens during allergy shots? — Most people take an antihistamine before each visit for allergy shots. Common antihistamines include loratadine (sample brand name: Claritin), cetirizine (sample brand name: Zyrtec), and fexofenadine (sample brand name: Allegra).

When you get to the office, the doctor or nurse will ask you for your name and birth date to make sure that you get the right shot. They will make sure that you are healthy enough to get the shot that day. If you have asthma and are having more symptoms than usual, or if you are sick with a fever, you might need to wait and get your shot another day. It is best to call the office before your appointment and check.

You might get just 1 or a few different shots, depending on how many things you are allergic to. After getting the shots, you will need to stay in the office or clinic for 30 minutes to make sure that you do not have a serious reaction to the shot.

What can I do to make my shots as safe as possible? — Getting allergy shots has risks. But if you follow your doctor's instructions, allergy shots are very safe. Every time you go to get your shots, the following things should happen:

●Your doctor or nurse will make sure that you took an antihistamine, if you were told to do this.

●They will ask you if you had any reactions after your last shot.

●They will ask if anything has changed with your health since your last shot. For example, they need to know if you are taking any new medicines, have any new medical problems, or have gotten pregnant. They will also want to know if you are having asthma symptoms or have a fever.

Answer all of your doctor's or nurse's questions truthfully. Your answers help tell them if you could be at higher risk that day for a serious reaction to the shot.

After you get your shot, you will need to stay in the office or clinic for 30 minutes. This is important because most serious reactions to the shots happen in this time frame.

You should also avoid vigorous exercise for at least a few hours after getting the shots. Exercise can make your body absorb the shots faster than it is supposed to. This could put you at risk for an allergic reaction.

What type of reactions can happen after an allergy shot? — There are 2 types of reactions to allergy shots. The area where the shot was given might turn red, swell, and itch. This is called a local reaction. It can be uncomfortable, but it isn't dangerous.

In rare cases, people get anaphylaxis from an allergy shot. Anaphylaxis caused by allergy shots can be dangerous. It can even cause death if it's not treated right away. If a person gets anaphylaxis, it usually happens within 30 minutes of getting the shots. If this happens in the doctor's office, it can be treated quickly with a shot of a medicine called epinephrine. This is why it is important to stay in the office or clinic for at least 30 minutes every time you get allergy shots. This is also why allergy shots should always be given in a doctor's office and not at home.

How often and how long do I need allergy shots? — Most people get allergy shots for 3 to 5 years, although some get them for longer. The first few months, the shots are given 1 to 3 times a week. During this time, the shots get gradually stronger, and allergy symptoms start to improve. After the shots have reached full strength, they are usually given once every 2 to 4 weeks. Symptoms then keep improving over the first few years.

Are there other things I can try besides allergy shots? — There might be. There is a form of treatment given as a pill that dissolves under the tongue. This is called "sublingual immunotherapy." This treatment doesn't involve getting shots. But it is only available for a few types of allergies.

Sublingual immunotherapy is given every day for several months of the year or year round. The first dose is given in the doctor's office, but after that, it is given at home because it's very safe.

More on this topic

Patient education: Environmental allergies in adults (The Basics)
Patient education: Insect allergy (The Basics)
Patient education: Anaphylaxis (The Basics)
Patient education: How to use an epinephrine autoinjector (The Basics)
Patient education: Environmental allergies in children (The Basics)

Patient education: Allergic rhinitis (Beyond the Basics)
Patient education: Trigger avoidance in allergic rhinitis (Beyond the Basics)
Patient education: Allergic conjunctivitis (Beyond the Basics)
Patient education: Using an epinephrine autoinjector (Beyond the Basics)