Immunotherapy: Allergy Injections
Immunotherapy (allergy injection) is a treatment designed to modify the sensitivity of the allergic patient so that exposure to offending allergens (pollens, dust, molds, animal danders, etc.) will result in fewer symptoms. It was first described by Leonard Noon in 1911 and has been used successfully since then for allergies and allergic asthma.
What is Immunotherapy?
Immunotherapy is performed by administering extracts of substances to which individuals have been found sensitive. The practice of immunotherapy has changed substantially over the last two decades. Standardized extracts have been developed, optimal doses have been established, and schedules for extract administration have been determined. Allergy injections will gradually decrease the allergy antibody level and modify the sensitivity of the immunologic cells to specific allergens. These changes allow the patient to withstand exposure to specific allergens with reduced allergic reactions.
How Immunotherapy Works
There are two phases of immunotherapy administration:
- The initial build-up phase. Here, the dose and concentration of extract are slowly increased.
- The maintenance phase. The patient receives his optimal immunizing dose over a period of time.
Allergy injections are typically given once a week, initially during the build-up phase until the maintenance or predetermined target dose is reached. This usually requires four to six months or longer depending upon the frequency and severity of local reactions and the number of missed doses. If allergy injections are given more than once a week, the maintenance dose can be achieved sooner than 4 to 6 months. Clinical improvement usually occurs within the first one to two years depending upon the regularity of the allergy injections and the dose reached.
Once the maintenance dose is reached, medications may be reduced and the interval between allergy injections may gradually be increased to two to four weeks depending upon the patient’s symptoms and reactions. Allergy injections are usually continued for three to five years or more after clinical benefit is achieved to reduce the chances of relapse once the injections are discontinued. However, severe allergic disease may require longer periods of treatment. Ideally, the patient should have a marked reduction of symptoms and be able to be maintained on a minimal amount of medication for at least a year. The duration and changes in therapy must be specifically tailored for each individual patient.
Regular follow-up visits with the doctor are essential in determining how the immunotherapy program is progressing and whether modifications need to be made. Allergy injections should always be given by trained personnel in a medical facility with a doctor present. Allergy injections should never be given at home.
In order to increase the dose most effectively and efficiently, the patient must adhere regularly to the allergy injection schedule. There are generally four vials in the building program, but in highly sensitive patients, there may be a larger number.
Each vial is ten times stronger than the previous one. Maintenance doses are usually achieved in the fourth or highest tolerated vial but this is variable and specific for each patient. Many patients reach their maintenance doses in the lower vials.
Reactions to Immunotherapy
There are several types of reactions that may occur with allergy injections: local and systemic.
The patient may note a local reaction consisting of redness, itching, or swelling at the site of injection. Rarely, a patient may experience a generalized reaction of increased sneezing, running nose, cough, tightness in the throat or chest, or shortness of breath. On rare occasions some patients experience lightheadedness, faintness, nausea and vomiting, hives, and under extreme conditions, shock.
Due to the possibility of a reaction, a patient must wait at least 30 minutes after each injection, and have the site checked before leaving. Some patients are required to wait more than 30 minutes. An antihistamine is generally recommended on the day of the allergy injection. Reactions are more likely to occur during the build-up phase but may occur at any time during the course of treatment. If any generalized reaction occurs after leaving the office, immediately call and return to the office. Any local reaction not noted in the office should be reported to the nurse before the next injection is given.
Injections are withheld if:
- The patient has had a fever, flu-like symptoms wheezing or other asthmatic symptoms within the previous 72 hours
- The patient is on an antibiotic started within the previous 48 hours, or has been given an immunization that day.
A parent or legal guardian must accompany minors unless written permission is given in advance. Please inform the nurse if any new medications have been started or if you are pregnant. You may not take allergy injections if you are on beta-blocking medications.
It is strongly suggested that all patients on allergy injections have an epinephrine auto-injector with them and show the nurses before the shot can be given.
Waiting Times for Allergy Injections (4/30/2014)
Periodically, expert panels are convened by the United States Food and Drug Administration and the U.S. National Institutes of Health to review and re-formulate national guidelines for various aspects of medical practice. These meetings allow experts to make recommendations based on the latest developments and knowledge in many fields of medicine.
Recent guidelines specify a 30 minute waiting time after allergy injections. This represents a change for our patients. The guidelines further specify longer than 30 minute waiting times in certain selected cases.
Effective immediately, we are requiring our immunotherapy patients to wait 30 minutes after allergy injections as we follow the national guidelines.
We apologize for any inconvenience.