Allergen Immunotherapy, or "allergy shots," involve injecting over time increasing amounts of the substance to which your child is allergic. This process leads to a change in the immune system and a decrease in the symptoms that would otherwise follow allergen exposure. Conditions treated with immunotherapy include allergic rhinitis, allergic conjunctivitis, asthma with a strong allergic component and insect sting allergy.
The first injection consists of a small amount of the least concentrated extract. Each week the dose is gradually increased until the maintenance dose (highest concentration) is reached. This maintenance dose is reached in about 24 weeks.
After six weekly injections at the highest dose, the time between injections is then increased to every two weeks, then three weeks and finally four weeks. After about one year, the patient will be on a monthly injection schedule. Please see sample "Kardex" (sheet we give out with the extract to record injections given).
Injections should be given regularly to effectively reduce symptoms. Improvement in symptoms may begin several months after maintenance doses are reached. Near maximum benefits are usually seen if the first year of therapy is completed before the next pollen season. Maximum benefit may not be reached until the second pollen season after treatment is begun. Generally, patients receive injections for about three to five years, at which point the symptoms usually do not return if immunotherapy is stopped. If the therapy is clearly beneficial, some specialists will recommend that the monthly injections continue for at least five or even seven years.
Injections should be given under the direct supervision of a physician. We will give the initial injections of new extract(s) in our office. Then injections may be given in your child's primary care physician's office, with follow-up visits at regular intervals in our office to monitor progress and provide new or renewal extracts.
Generally, 85 to 90 percent of patients who are receiving high dose maintenance immunotherapy will have a significant improvement in their allergic symptoms as well as a reduction in their need for additional medication.
Immunotherapy is best prescribed when:
The drawbacks of immunotherapy include inconvenience, discomfort, and the chance of reactions. Many patients develop swelling at the site of the injection. Antihistamines, ice and elevation usually control these local reactions quite well.
Generalized allergic reactions, while rare, can be serious. Most of the severe reactions occur within 30 to 40 minutes. We therefore ask that your child stay in their physician's office for 30 minutes after each injection.
This is to monitor for any reactions to the immunotherapy. Any reaction at the site of the injection (local reaction) needs to be measured. The size of the reaction is used to determine the dose for the next injection. While rare, serious side effects (severe systemic reactions) may occur, usually within thirty minutes. If you cannot wait the thirty minutes, you need to reschedule your appointment.
No. Injections can only be received in a medical facility in the presence of a physician. Although you may have access to someone capable of administering injections, severe reactions to immunotherapy need to be treated by a physician who has access to life-saving medications and medical equipment.
The patient can receive injections with mild illnesses, such as upper respiratory infections. The injection should not be given if the patient has a fever or is wheezing. Always notify the nurse before receiving the injection if your child is having severe allergy symptoms or coughing.
Yes. The patient should not exercise for two hours after receiving the injection.
In addition to local reactions within the first half hour (a hive at the side of the injection), delayed reactions consisting of redness and swelling at the site of the injection can also occur. These may begin as early as one hour after the injection is given and they may last as long as 12 to 24 hours. Ice, elevation and antihistamines are helpful. Make sure you notify the nurse giving the injection if there is a reaction so that the next dose can be adjusted. Systemic reactions are rare, and include allergic symptoms of the eyes and nose, hives, swelling, coughing, wheezing, and decreased blood pressure. Any severe symptoms should be treated in the emergency department after beginning appropriate immediate measures.
If your child is under eighteen years old, you need to be present to give consent for the nurse to administer the injection and for the physician to treat any reactions.
Although the injections do not need to be exactly every seven days, you must wait at least 48 hours in between injections.
It is not a problem if injections need to be missed for occasional vacations, illnesses or other responsibilities. Depending on the time interval between injections, the next dose may need to be reduced. Make sure the nurse is aware of the time lapse before receiving the next injection. If you need to miss doses often, immunotherapy should not be started or continued.
Reviewed by: Allergy Section
Date: October 2002