Immunotherapy / Desensitization
(Allergy Shots Or Drops)
What is allergen specific immunotherapy / desensitization?
Allergen specific desensitization or "Immunotherapy" is a treatment program where the allergens that you are allergic to are administered in gradually increasing doses to a level that induces tolerance or a non-reactive state. This treatment program is effective in decreasing allergic symptoms brought on by environmental allergens, such as pollens, mold, animal dander and house dust. The allergens are mixed together in a serum or vaccine and administered weekly to several times a week over the first year, then spreading to less frequent intervals once the target or maintenance dose is reached. The total duration of treatment usually takes 3-5 years to be completely effective. The effect of immunotherapy is disease modifying and persists long after the treatment period. Medications alleviate symptoms but do not cure or modify the underlying problem.
How does it work?
Treatment begins with very dilute concentrations of the allergens you are allergic to (in order to avoid allergic reactions), gradually increasing to levels that induce immunologic tolerance or non-reactivity. It is the immunologic reactivity to these allergens that causes symptoms in the first place. Tolerance is achievable in 90% of all patients, though this tolerance may represent a 20% to 70% decrease in reactivity on average. This means that some patients achieve near complete tolerance while others achieve only partial tolerance. Because tolerance may be only partial, it is important to give medications and allergen avoidance measures (where applicable) a chance before committing to immunotherapy. The most severe symptoms of allergies such as recurrent sinus infections or the early stages of asthma respond best to immunotherapy. For many individuals, allergen immunotherapy can provide relief and a way of life that would never have been possible before.
Recognized indications for immunotherapy:
- Allergic rhinitis, asthma or eczema not responding to conventional medical therapy in the form of allergen avoidance and prescription medications.
- A desire to decrease reliance on medications or avoidallce measures, and still maintain adequate control of allergic symptoms.
- In patients at risk for asthma a desire to prevent progression to asthma when signs of allergic disease first become evident such as allergic rhinitis, eczema or the early stages of asthma.
What forms of immunotherapy are available?
- Standard Injection (shots)
- Rush Injection (shots)
- Sublingual (drops)
1. Standard injection (shots) immunotherapy
Injections are started at very dilute allergen concentrations (E vial 1:10,000 dilution) and gradually increased to a maintenance dose (A vial undiluted). Injections are given bi-weekly or weekly until the maintenance dose is reached. It usually takes 8-12 months to reach a maintenance dose. When the maintenance dose is reached, the injection interval is gradually spread from every 2 to every 4 weeks during the second and third years.
Question - Do I need to come every week without fail?
If it's been less than 20 days since your last injection the dose is increased per build-up schedule; if it's been >20 days but <30 days no progression occurs and your last dose is repeated; if it's been >30 days the dose is decreased one or more levels. So if you come every other week for injections, you can still progress according to schedule. However, it will take you twice as long to reach maintenance levels and a therapeutic benefit. Once the maintenance dose is reached injections are spread out to every two weeks then to once monthly.
Question - When will I start to feel better ?
Improvement can occur early within 2-4 months, though typically is not evident until the maintenance dose is achieved at 8-12 months. The initial improvement seen on reaching maintenance can be mild and medications may still be needed to control symptoms. Significant improvement allowing medication reduction usually occurs in the second or third year of treatment. In some patients, allergy symptoms can worsen during the build-up phase to maintenance. This problem can be addressed with serum dose reduction or slowing of the injection schedule. These adjustments must be made by our nursing staff, so it is important to communicate any reaction or symptom flare up occurring after your last injection.
Question - How long do I need to continue immunotherapy?
After completing 3 years of treatment, improvements become pemlanent or long-lived (> 10 years). However, symptom improvement continues as long as injections are given. Thus, the total duration of therapy is usually 3-5 years.
Question - Are there any side effects or risks with immunotherapy?
Known side effects are limited to allergic reactions from the injection. Reactions may be immediate (within 20-60 minutes) or delayed (occurring between 2-48 hours after injection). Local reactions limited to the injection site are common and consist of swelling, redness, itching or tenderness. Our nurses will record all immediate reactions; however, delayed reactions should be reported before your next injection. Systemic reactions may include hives, swelling outside the injection site, generalized itching or flushing, nasal congestion or drainage, wheezing, shortness of breath, cough, hoarseness, throat tightness or constriction, fainting and nausea or vomiting. Immediate systemic reactions comprise the biggest risk of immunotherapy and though rare, can be life threatening. It is for this reason that injections are given in a physician's office with a required observation time of 20 minutes. Delayed systemic reactions generally appear as a worsening of your usual allergy symptoms and though not as serious as immediate systemic reactions, they need to be reported before your next injection to allow for dose adjustment.
Question - Can I get my injections at home or another physician's office?
Injection immunotherapy can't be given at home due to the low but real risk of systemic reactions. Injections can be given by another healthcare provider if they perfoml this service and can handle immediate systemic reactions (injectable epinephrine available on site). In this case, AIR Care will release current Serum vial to you; then retum the vial and injection record when complete for release of the next serum viaL
2. Rush injection (shots) immunotherapy
The rush protocol consists of nine injections at 30-minute intervals on the first day, taking the injection dose to near maintenance. This dose is increased to full maintenance with weekly injections over the next 2~3 months. Once the maintenance dose is achieved, injections are spread to once monthly provided symptoms remain stable. The total recommended duration of therapy is similar to the standard protocol at 3-5 years.
Advantages of Rush
The advantages of this protocol are quicker symptom improvement and quicker spread to monthly injections. This occurs because the maintenance dose is achieved much sooner. There are indications that the rush protocol is more effective than standard immunotherapy, though this may relate to better recognition of symptom relief due to the rapid achievement of a maintenance dose.
Risks of Rush
We do see more systemic reactions during the rush protocol (approximate incidence 40%), though these are easily treated with available medications in the office. The rush protocol is administered with close nursing supervision through our in office infusion clinic. The entire protocol takes 6-8 hours and patients are able to go home at the end of the procedure provided no serious reactions are present.
3. Sublingual (drops) Immunotherapy
In the sublingual protocol, allergen extracts are given as drops under the tongue and then swallowed. This form of immunotherapy has been employed in Europe tor over 10 years and data obtained from this experience indicate that sublingual immunotherapy is effective in symptom reduction (20% - 50% reduction on average) though not as effective as injection immunotherapy (40% - 70% reduction on average). Our own data have shown that at 6 months Sublingual is not as effective as shots, but that at 12 months and 24 months of continuous therapy it is as, if not more etIective than shots.
Advantages of sublingual immunotherapy
The real advantage of the sublingual route is its safety and absence of needles/shots. Reactions are less frequent and milder compared to injection immunotherapy. Because of this, sublingual immunotherapy can be given at home. This allows patients unable to comply with weekly office injections the ability to receive allergen specific desensitization at home. Patients that have shown sensitivity to injection immunotherapy with systemic reactions can also benefit from the relative safety ofthe sublingual route.
Risks of subUngual immunotherapy
The risks are similar to injection immunotherapy except that the incidence and severity of systemic reactions are less.
Sublingual (drop) build-up schedule
In this protocol allergen serum drops are administered daily to three times weekly starting at E vial 1:10,000 or D vial l:I ,000 dilution increasing from 1 to 10 drops over two to four weeks; the patient then returns to our office for the next (higher concentration) serum vial. This progression continues until A vial (undiluted allergen serum) is reached. The build-up to maintenance may take two to four months. The maintenance dose is continued three times weekly for one year, then two times weekly for one year and then once weekly for a year. If immunotherapy is continued beyond three years retesting and serum adjustment is recommended.