Allergen immunotherapy, or "allergy shots," involves injecting increasing amounts of the substance to which your child is allergic over a period of time. This process leads to a change in the immune system and a decrease in the symptoms that would otherwise follow allergen exposure.
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:
- Symptoms are moderate to severe and occur for at least several months each year
- Symptoms have not responded well to a thorough medical plan
- Side effects of medications cannot be tolerated or multiple medications are not desired
- Environmental control measures have been undertaken and those things to which your child is allergic cannot be easily avoided
Improvements in your child's 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.
How allergy shots are administered
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 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.
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.
Allergy shoots should not be given if your child has a fever or is wheezing. Always notify the nurse before receiving the injection if your child is having severe allergy symptoms or coughing.
The drawbacks of immunotherapy include inconvenience, discomfort, and the chance of reactions.
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. Antihistamines, ice and elevation usually control these local reactions quite well.
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. Most of these severe reactions occur within 30 to 40 minutes, which is why we ask that your child stay in their physician's office for 30 minutes after each injection.
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. If you cannot wait the thirty minutes, you need to reschedule your appointment.
Patients also should not exercise for two hours after receiving the injection.
Reviewed by: Allergy Section
Date: October 2002