Allergy shots, also known as immunotherapy, are the most widely used treatment in the United States to help a person become less allergic or more tolerant. Allergy shots contain no drugs or medications but rather the actual substances to which a person tests allergic. The injection of increasingly stronger concentrations of specific allergens (substances to which one is allergic) can lead to gradual and significant reduction in allergic symptoms. Allergy shots have been proven to be helpful for hayfever and cedar fever (nasal and eye allergies), asthma, eczema (in some cases) and stinging insect allergy (bees, wasps, hornets, fire ants, etc.). Venom shots (for stinging insects) can reduce the possibility of life threatening allergic reactions to less than 5%. Unfortunately allergy shots are not effective for food allergy or medication allergy.
Your doctor will use the results of your allergy testing (skin or blood testing) and your history of symptoms to determine if you are a good candidate for allergy shots. Appropriately selected patients who receive high dose allergy shots usually experience an 80% or greater reduction in symptoms after 12-18 months of injections. Reduction in symptoms normally begins within 3 months of starting shots. Allergy shots are continued at gradually increasing intervals for 3-5 years in most patients. Most patients will continue to have reduced allergy symptoms for 5 years or longer after a course of allergy shots. About two thirds of patients will notice gradually increasing allergy symptoms 5-10 years after injections are stopped. A second course of allergy shots can be considered if symptoms become very bothersome.
Allergy shots are started at a very low dosage and gradually increased to a high or "maintenance" dose over a period of months. The initial shots ("build up phase") are more dilute and the dosage or concentration is increased at each visit unless the patient has had a reaction to a previous injection. The "maintenance" dose is the highest dose that a patient can receive without significant reaction. For most patients it takes 18 visits to reach the "maintenance" concentration and then 10 more visits to reach the highest dose. Some patients don't tolerate higher doses so their "maintenance" dose is lower. In most patients the highest tolerated dose is effective in reducing their allergies.
In our office patients can receive allergy injections up to 3 times a week in the "build up phase". We generally recommend at least one day between injections. No appointments are needed for injections and patients may come on a different day or different time for each injection (see our Hours). In general it is necessary to come at least once a week to build injections in a timely manner though it is OK to skip injections for a week here and there. When a patient reaches the "maintenance" concentration we recommend injections only once weekly. Weekly injections are continued through the first year of allergy shots. Patients then meet with their physician to determine their response to shots. Most patients can take their shots every 2 weeks during the second year of treatment and monthly thereafter with continued reduction in allerygy symptoms.
Every allergy injection carries a risk of an allergic reaction. Fortunately, most of these reactions are minor and require no therapy. However, any injection can result in a potentially life threatening reaction (systemic reaction). For this reason we require patients to wait in our office for 30 minutes after each injection. Most serious reactions begin within minutes of the shot and can be quickly and effectively reversed with a shot of epinephrine and an antihistamine pill.
It is common to have an itchy swollen bump on the arm at the site of the allergy shot (local reaction). This can be treated with an icepack and an antihistamine pill. It is important to inform our injection nurse if you have a delayed reaction to your allergy shot. Dosage adjustments may be necessary or the buildup schedule might be lengthened. It is OK to take an antihistamine like Allegra, Zyrtec or Claritin before you take you shots if you find this helpful.
Cluster Immunotherapy refers to an accelerated schedule for building up allergy shots. For inhalant allergies (pollen, mold, dust, pets) the first 2 buildup vials can be completed in two 3 hour sessions. This is the equivalent of 12 injections in 2 visits. The usual weekly schedule is then continued until the "maintenance" dose is reached. With cluster immunotherapy the maintenance dose is reached much more rapidly and the reduction in allergy symptoms occurs more quickly. Patients are generally advised to take antihistamines prior to cluster sessions.
For venom immunotherapy, cluster injections allow the patient to reach the protective dose of venom shots in a much shorter period, gaining protection against serious reactions to stinging insects more quickly. Cluster allergy shots have been shown to have a slightly increased risk of local and systemic reactions. Patients are monitored closely during cluster immunotherapy and emergency treatment for reactions is immediately available.
The above is a general guide to allergy shots but is not complete or exhaustive. If your physician recommends allergy shots you will receive additional information including detailed handouts.