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What are Allergy Shots?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Allergy shots are a series of injections given to decrease someone's sensitivity to an allergen. A full course of allergy shots can take up to five years to complete, making it a serious commitment, but it can greatly improve quality of life. For patients with very severe allergies, allergy shots can also be lifesaving, as they allow the patient to be exposed to the source of an allergy without developing fatal symptoms.

Also known as immunotherapy, allergy shots involve introducing very small amounts of an antigen to a patient's body. In the build up phase, in which shots are taken one to three times a week for three to seven months, the amount of the antigen is gradually increased with each shot. The goal is to expose the body without triggering an allergic reaction, allowing the patient's body to recalibrate itself so that it will not longer recognize the allergen as a threat. In the maintenance phase, which requires one shot a month for two to five years, the patient is given regular doses to continue the desensitization.

Allergy shots can take up to 5 years to complete for effectiveness against reactions.
Allergy shots can take up to 5 years to complete for effectiveness against reactions.

When allergy shots are given, it is usually because a patient has very severe allergies, or experiences allergic reactions more than three times a year. Patients who find it difficult to avoid an allergen can also benefit from shots, as can patients who have tried other means of allergy control which turned out to be unsuccessful. Immunotherapy is not recommended for people with heart conditions or severe asthma, or for pregnant women.

Allergy shots may help with seasonal allergies.
Allergy shots may help with seasonal allergies.

Insect allergies, seasonal allergies to things like ragweed, and indoor allergies can all be treated with allergy shots. Food allergies cannot. Before offering allergy shots to a patient, a doctor will usually conduct an interview to collect information about the patient's history and current medications, to make sure that he or she is a good candidate for the shots. In certain cases, a doctor may recommend rush immunotherapy, in which the patient gets increasingly large doses every few hours in a controlled environment like a hospital for rapid desensitization.

Allergy shots may be used to reduce the severity of symptoms.
Allergy shots may be used to reduce the severity of symptoms.

Typically, patients are asked not to exercise for at least two hours before and after allergy shots. They will also need to stay for monitoring for at least 30 minutes after a shot to confirm that no adverse reactions are occurring. Allergy shots are not risk free, and patients can sometimes develop allergic reactions and other serious responses, which makes this monitoring period important. If a patient does start to feel strange after a shot, he or she should report the feeling immediately so that medical care providers can take action.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

Kat919

@MrsWinslow - If you think you might be pregnant soon, within six months to a year, I think starting the shots would be a waste of money. Depending on your insurance, the start-up cost can be high because you have to buy the serum, which can be hundreds of dollars.

They will not *start* shots while you are pregnant, but if you are well-established with them when you *get* pregnant, you can usually continue at a maintenance dose. But it takes a while to get to that maintenance dose, and if you get pregnant first, they might just want you to stop. As far as I know, they don't affect breastfeeding.

*But,* you usually have to take antihistamines with allergy shots to minimize reactions. They say to take an antihistamine the day before, the day of, and the day after, and possibly a different kind of antihistamine the day of. And antihistamines work against your body's efforts to get pregnant by drying up your fluids. Another reason why it might be better to wait until after baby to try the shots, or alternatively to start the shots but stop trying to conceive for a while.

MrsWinslow

This might sound silly, but I had no idea that allergy shots were immunotherapy - I think I thought they were just injections of stronger medicines! My allergist has recommended allergy shots for me, so I'm researching it. I moved to a new area recently where I plan to stay for a long time, and the allergens are different from what I am used to and I'm just really suffering!

But I'm concerned about allergy shots and pregnancy because I am trying to conceive. If I got pregnant, would I have to stop the shots and start all over again after I had the baby? What about if I was breastfeeding? Does anyone have experience with this?

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    • Allergy shots can take up to 5 years to complete for effectiveness against reactions.
      By: Igor Mojzes
      Allergy shots can take up to 5 years to complete for effectiveness against reactions.
    • Allergy shots may help with seasonal allergies.
      By: bsites
      Allergy shots may help with seasonal allergies.
    • Allergy shots may be used to reduce the severity of symptoms.
      By: Lsantilli
      Allergy shots may be used to reduce the severity of symptoms.
    • Allergy shots are most frequently used to reduce the reaction to seasonal allergens such as pollen.
      By: FedeCandoniPhoto
      Allergy shots are most frequently used to reduce the reaction to seasonal allergens such as pollen.
    • Lightheadedness may occur as a result of seasonal allergies.
      By: vladimirfloyd
      Lightheadedness may occur as a result of seasonal allergies.
    • Food allergies can not be treated with allergy shots.
      By: jillchen
      Food allergies can not be treated with allergy shots.