The purpose of immunotherapy (allergy injections) is to decrease your sensitivity to allergy-causing substances, so that exposure to the offending allergen (pollen, mold, mites, animal dander, stinging insects, etc.) will result in fewer and less severe symptoms. This does not mean that immunotherapy is a substitute for avoidance of known allergens or for the use of allergy medications, but rather is a supplement to those treatment measures.
Allergy injections have been shown to lead to the formation of “blocking” or protective antibodies and a gradual decrease in allergic antibody levels. These changes may permit you to tolerate exposure to the allergen with fewer symptoms. You, in effect, become “immune” to the allergen. The amount of this immunization is different for each person and is, therefore, somewhat unpredictable.
To qualify for immunotherapy, there must be documented allergy to substances in the environment that cannot be avoided. Documentation of allergy can be either in the form of a positive skin test or a positive blood test. In addition to demonstrable allergy by one of the above tests, problems such as hayfever or asthma should occur upon exposure to the suspected allergen, or you may have a history of a severe reaction to an insect sting. Due to the inherent risks of immunotherapy, avoidance measures and medical management should usually be attempted first.
Improvement in your symptoms will not be immediate. It usually requires 3 to 6 months before any relief of allergy symptoms is noted, and it may take 12-24 months for full benefits to be evident. About 85-90% of allergic patients on immunotherapy note significant improvement of their symptoms. This means that symptoms are reduced, although not always completely eliminated.
WHAT ARE THE CHANCES OF STOPPING IMMUNOTHERAPY SUCCESSFULLY?
- After 4-5 years of high-dose continuous immunotherapy, between 60-80% of patients should be able to stop successfully.
- The only sure way to find out is to STOP.
If a patient stopped unsuccessfully, symptoms characteristic of returning allergy problems should not occur for at least 12 months. Between 12-24 months, 30% experience the return of allergy symptoms, and 50% the third year off immunotherapy.
Allergy injections are usually begun at a very low dose. This dosage is gradually increased on a regular basis (usually 1-2 times per week) until a therapeutic dose (often called the “maintenance dose”) is reached. The maintenance dose will differ from person to person. Injections typically are given once or twice per week while the vaccine dose is being increased. This frequency reduces the chances of a reaction and permits the maintenance dose to be reached within a reasonable amount of time. After the maintenance dose is determined, the injections can usually be given every one to two weeks.
Immunotherapy Time Line
|DAY ONE||6-8 MONTHS||YEARS 2-4 (5)||END OF
4TH (5TH) YEAR
|START||WHEN INJECTIONS ARE CRITICALLY JUDGED FOR EFFECTIVENESS||CONTINUE|
|INJECTIONS GIVEN TWICE WEEKLY FOR 9-16 WEEKS, THEN WEEKLY||INJECTIONS GIVEN WEEKLY UNTIL THE END OF THE FIRST TWELVE MONTHS||INJECTIONS GIVEN EVERY OTHER WEEK (TWICE MONTHLY) FROM YEARS 2-4 (5)||DISCUSS STOPPING, OR CONTINUING INDEFINITELY|
Duration of treatment
It usually takes 3 to 6 months to reach a maintenance dose. This may be longer if there are vaccine reactions or if the injections are not received on a regular basis. For this reason, it is important that the recommended schedule be followed. If you anticipate that regular injections cannot be maintained, immunotherapy should not be started. Immunotherapy may be discontinued at the discretion of Dr. Moore if the injections are frequently missed, as there is an increased risk of reactions under these circumstances. Most immunotherapy patients continue treatment for 3-5 years, after which the need for continuation in reassessed.