Type of Medication

Flu shot image Medication administered as an injection just under the skin to help decrease allergic reactions.

What Allergy Shots Are Most Frequently Prescribed For

Allergy shots don't work on all allergies or on all people with allergies. For example, they're extremely dangerous for food allergies .

Allergy shots should be considered for patients with severe symptoms that are difficult to control with medications (eg, Allegra , Claritin , inhaled corticosteroids, Singulair ) 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 allergic. 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 takes at least six 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:

  • Severe asthma that is not controlled with medication
  • Heart problems
  • Taking a beta-blocker for heart problems

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 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 while receiving shots.

Dosing Schedule

Allergy shots are given year-round. For the first six months, you will get one to two shots per week. Then, a maintenance dose is injected every few weeks to once a month. You'll receive these monthly shots for three to five 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, and life-threatening reaction called anaphylaxis or anaphylactic shock can occur. Such a reaction is very rare. Having your shots on a regular schedule decreases the risk of anaphylaxis.

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 immediately.

An alternative treatment to allergy shots (immunotherapy) is sublingual immunotherapy (SLIT) that does not require administration of an injection. Instead, a small amount of a liquid is given under the tongue. It eliminates the need for weekly or monthly doctor visits. The specific details of this method have not been worked out, and there are no FDA approved products available for the administration of this type of immunotherapy. In Europe, it has been successfully used for many years, however the approach to immunotherapy in Europe is different than in the United States, SLIT may be a viable alternative in the future.