Allergy shots (immunotherapy) for allergic rhinitis
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Allergy shots (immunotherapy) are a method of treating allergic rhinitis in which small doses of substances that you are allergic to (allergens) are injected under the skin. This eventually decreases your reaction to the allergen by decreasing the inflammation and the amount of chemicals released during an allergic reaction. 1 Over time, allergy shots can decrease how severely you react when exposed to allergens.
Extracts of various types of grasses, weeds, trees, dust mites, molds, and animal dander can be used in immunotherapy. Because the allergen you are allergic to is used in immunotherapy, skin testing must be done first to identify the allergen.
A solution of dilute salt water (saline) that contains a very small amount of the allergen or allergens is injected under the skin. At first, you get a shot once or twice a week. The amount of allergen injected is increased slightly each time, unless you have an allergic reaction to the shot.
After about 4 to 6 months of weekly shots, you are usually getting an optimal amount of allergen in the shot. This is called the maintenance dose. Once you reach maintenance level, you get the same dose in shots every 2 to 4 weeks for another 4 to 6 months.
The period between shots is gradually increased to about a month. After 1 year of maintenance, you are evaluated to see whether allergy symptoms have decreased. If the allergy symptoms have not decreased in that time, the allergy shots should be stopped. If symptoms have improved, you may continue to get monthly shots for up to 3 to 5 years. 2
A variation of this treatment is called rush immunotherapy, which increases your tolerance to an allergen very quickly.
what To Expect After Treatment
You receive allergy shots in your health professional's office. You will stay in the office for a short time after getting an allergy shot to be monitored for possible life-threatening reactions (anaphylaxis) to the injected allergens.
Redness and warmth at the shot site are common but go away after a short period of time.
Why It Is Done
Allergy shots can reduce your reaction to allergens. They may also prevent the development of asthma in children with allergic rhinitis. 3 Allergy shots may be considered when: 2
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 difficult to avoid.
Avoiding allergens and using medications do not control symptoms, or you have to take medications all the time to control symptoms.
Side effects of medications are a problem.
You want a treatment for the underlying 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. 4
How Well It Works
Allergy shots are effective in treating allergic rhinitis and allergic asthma. 3 As many as 85% of people who take allergy shots find that their allergic rhinitis symptoms improve. 5 The shots reduce symptoms in those allergic to pollens, animal dander, dust mites, mold, and cockroaches. 3 Allergy shots can be effective for 3 years or longer after the shots are stopped. 6
Allergy shots have resulted in: 3
Symptoms of dust mite allergies being about 3 times better than before therapy.
Symptoms of pollen, mold, or animal dander being about 4 times better than before therapy.
Although you still need to practice allergen avoidance, allergy shots can often decrease or stop medications for allergic rhinitis.
Risks
Allergy shots 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), the shots are given in a health professional's office where emergency care can be provided, if needed.
If you or your child has another condition, such as asthma, you may be at increased risk for a severe reaction (anaphylaxis) to the shots and, possibly, death. 2 You should have the asthma well controlled before receiving allergy shots. 2
What To Think About
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.
Children under age 2 should not have allergy shots. Children ages 3 to 4 may find it difficult to receive many shots over a long period of time; talk with your health professional about whether allergy shots are suitable for your child.
Your child's asthma needs to be well controlled to have allergy shots. This generally is done through an asthma action plan. For more information, see the topic Asthma in Children.
Older adults may be taking medications or have other medical conditions that may increase the risk of a severe reaction to allergy shots.
Most reactions to allergy shots occur 20 to 30 minutes after the injection. You should stay at your health professional's office for at least this amount of time.
You must report any delayed reaction to an allergy shot. Late reactions can happen any time within 24 hours after a shot. Reactions may be local (such as a large, red or raised area around the site) or overall body reactions (such as trouble breathing).
Allergy shots take 3 to 5 years to complete and are expensive. It may take up to 1 year for allergy symptoms to improve. During your treatment, you should be evaluated by your health professional at least once every 6 to 12 months.
Pregnant women who are already taking allergy shots may continue them. However, it is not recommended that they be started during pregnancy.
Allergy shots should not be used when you:
Have had a recent heart attack, unstable angina, or other heart conditions or are taking beta-blockers.
Are unable to communicate (can't tell the health professional about reactions to shots). Most health professionals do not give allergy shots to children under age 5.
Have an immune system disease (such as AIDS).
