Allergy shots are a type of immunotherapy treatment in which 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.
Other ways to get this treatment are called cluster or rush immunotherapy, in which you reach the maintenance dose more quickly.
What To Expect
Allergy shots are usually given in a doctor's office. It is normal to stay in the doctor's office for a short time after getting an allergy shot to be watched for possible serious reactions to the injected insect venom.
Redness and warmth at the shot site are common. But they'll go away after a short 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.
Allergy shots are safe if the shots are given correctly. The most common side effects are redness and warmth at the shot site. Some people may have reactions near where they had the shot, such as itching, hives, or swelling of the skin. More serious but less common side effects include symptoms that affect other parts of the body. Examples are hives, itching, and trouble breathing.
In rare cases, a person may have a severe allergic reaction (anaphylaxis) to the shots. Because of this possibility, the shots are given in a doctor's office or other setting where emergency care can be provided if needed. You must report any delayed reaction that you have to a shot. Late reactions can happen anytime within 24 hours after a shot.
Allergy shots may not be right for you if you:
- Have 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.
- Have an autoimmune disease, such as lupus.
- Are taking beta-blockers, such as propranolol (Inderal, for example). They are often used to treat heart conditions, glaucoma, migraine headaches, and high blood pressure.
- Are taking ACE inhibitors, such as captopril (Capoten, for example) or lisinopril (Prinivil, Zestril, or Zestoretic, for example). These are often prescribed for high blood pressure and a variety of heart conditions. Talk to your doctor first about the potential risks of allergy shots.
- Are not able to communicate about reactions to shots. Most doctors don't give allergy shots to children younger than age 5.
Current as of: April 20, 2022
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine