by Kassel K

Allergy Shots

(Desensitization; Hyposensitization; Immunotherapy)

Type of Medication

Flu shot image Allergy shots are injections given just under the skin to help decrease allergic symptoms or reactions.

What Allergy Shots Are Most Frequently Prescribed For

Evidence shows that both allergy shots and sublingual (under the tongue) therapy help reduce symptoms of allergies. Shots are most often prescribed for:
Allergy shots do not work on all allergies or on all people with allergies. For example, they are not used to treat food allergies.
Allergy shots should be considered for patients with severe symptoms that are difficult to control with medications and when other forms of treatment have failed.

How Allergy Shots Work

Allergy shots decrease your sensitivity to allergens by exposing you to increasingly larger doses of the allergens to which you are reacting. An allergen is a substance that can produce an allergic, or hypersensitive response, often called an allergy attack. Pollen, dust mites, and mold spores are common allergens.
First, your doctor will use skin or blood tests to determine what you are allergic to. Then, a shot is made from small amounts of these specific allergens. With repeated shots, your body becomes less sensitive to these allergens, causing you to have a less severe allergic reaction or none at all.
It can take as long as 12 months of regular shots before you notice relief of your allergy symptoms.

Precautions While Using These Medicines

Allergy Shots Should Not Be Taken Under These Conditions:

  • If you are having severe asthma that is not controlled with medication
  • If you are having heart problems
  • If you are taking a beta-blocker
  • Any children under the age of 5 years

Discuss Pregnancy with Your Doctor

Women who are pregnant should not begin allergy shots. However, if a woman has been receiving allergy shots for some time when she becomes pregnant, she may be able to continue. Discuss your options with your doctor.

Discuss Other Medications

Tell your doctor if you are taking or plan to take any medications, including over-the-counter drugs, for both allergic and nonallergic conditions. Your allergy shots may affect the use of other medications.

Continue Other Measures

Allergy shots can greatly reduce allergy symptoms, but are not a guaranteed cure. Therefore, you should continue to avoid known allergens and use your medications while receiving shots.

Dosing Schedule

Allergy shots are given year-round. For the first 3-6 months, you will get 1-2 shots per week (called the build-up phase). Then, a maintenance dose is injected every few weeks to once a month. You will receive these monthly shots for 3-5 years. After this time, you may be able to stop shots completely.

Possible Side Effects

Allergy shots are usually safe. However, because they contain a small amount of an allergen, there is a risk of an adverse reaction. This may be as mild as swelling and redness at the site of the shot, which can last for 1-3 days. However, a serious, life-threatening reaction called anaphylaxis can occur. Such a reaction is rare.
You will receive your shot in a doctor's office, and you will be asked to wait 30 minutes after the shot before leaving. If a bad reaction occurs, the medical personnel will be able to treat you right away.


American College of Asthma, Allergy, and Immunology
Family Doctor—American Academy of Family Physicians


Allergy Asthma Information Association
Health Canada


Allergic rhinitis. EBSCO DynaMed website. Available at: Updated July 14, 2014. Accessed December 23, 2014.
Allergy shots: Could they help your allergies? Family Doctor—American Academy of Family Physicians website. Available at Updated April 2014. Accessed December 23, 2014.
Allergy Shots: Tips to remember. American Academy of Allergy, Asthma and Immunology website. Available at: Accessed December 23, 2014.
Garcia-Marcos L, Lucas Moreno JM, Garde JG. Sublingual specific immunotherapy: state of the art. Inflamm Allergy Drug Targets. 2007;6:117-126.
Jacobsen L, Niggemann B, Dreborg S, et al. Specific immunotherapy has long-term preventive effect of seasonal and perennial asthma: 10-year follow-up on the PAT study. Allergy. 2007;62:943-948.
Pregnancy and allergies. American College of Allergy, Asthma andImmunology website. Available at: Accessed December 23, 2014.

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