Immunotherapy is like a vaccination against your allergies. Vaccine shots are to prevent infections; immunotherapy shots are to prevent allergies. However, the two work in opposite ways. Vaccinations prime the immune system to help the body react swiftly if the disease is encountered again, whereas immunotherapy dulls the reaction to allergens.
In the long term, allergy shots can minimize the need for antihistamines or other allergy
medications. Immunotherapy builds up your tolerance to specific allergens, so your body won’t overreact to them.
Immunotherapy shots are used for most airborne allergens, including tree, grass, and weed pollens, dust mites, and animal allergens. Immunotherapy shots can also be used to prevent severe sting reactions from honeybees, yellow jackets, hornets, wasps, or fire ants.
How does it work?
Your allergist will first confirm what you’re allergic to with allergy testing. Next, he or she will inject small amounts of allergens over the course of many months, periodically increasing the amount of allergens injected. After receiving each shot, you will need to stay in the doctor’s office for 20-30 minutes to see if you react adversely. Also, your allergist will ask you how you felt after getting the previous shot.
The injection schedule depends on the individual. Generally, 1-2 shots are given weekly in the beginning during the “dose building” stage. They eventually taper off to monthly “maintenance” shots. For some people, it may take up to 12 months to reach the maintenance dose.
Immunotherapy during Pregnancy:
Allergy shots (or allergen immunotherapy) can be safely continued during pregnancy if a woman has not had any serious reactions to the shots previously, but it is not advised that women begin shots or increase the dose of their shots while pregnant. This is because allergic reactions to the shots, which are uncommon but can be dangerous, occur more often during the initial, buildup stage, when the dose is being increased. A severe allergic reaction could cause low blood pressure in the mother, and the baby might not get enough oxygen for a few minutes. In addition, the treatment for a severe allergic reaction — which is epinephrine — could temporarily reduce the blood supply to the baby. So rather than taking these risks, allergists avoid beginning or increasing allergy shots during pregnancy, an approach accepted by professional allergy and obstetrical societies. There is some preliminary evidence that mothers who get allergy shots while they are pregnant may lower their baby’s risk of being allergic, but more study is needed before this can be considered fact.
The American College of Obstetricians and Gynecologists has issued new guidelines in the management of asthma symptoms in pregnant women, saying that “ it is safer for both fetus and mother for pregnant asthmatic women to continue to use their asthma medication in the lowest dose possible to manage symptoms during their pregnancy.”
Regarding allergy immunotherapy shots, the recommendation is as follows:
Women who already use immunotherapy (allergy shots) at or near maintenance level to improve asthma symptoms may continue getting shots during pregnancy. However, women should not begin immunotherapy during pregnancy. Allergy shots are typically given with lower doses of serum to start and then are gradually increased to higher levels. These escalating doses may cause anaphylaxis during pregnancy, which has been associated with maternal and fetal death.
A discussion of the risks and benefits of continuing allergy shots during pregnancy should be had between the patient and allergist, with input from the patient’s obstetrician, before deciding on a treatment regimen.