Allergy Injections – Frequently Asked Questions
What is Respiratory Allergy?
Allergy is an abnormal immune response to proteins (‘allergens’) we inhale with the air. Normal persons have Th1/IgG response, which means they can ‘tolerate’ the allergen. Allergic people have an intolerant Th2/IgE response, which leads to chronic inflammation of the respiratory passages resulting in Allergic Rhinitis, Sinusitis and Asthma.
What is Desensitization?
Allergy vaccines, given in gradually increasing doses, can block the Th2/IgE response, reverse it to the Th1/ IgG response so you can tolerate the allergens and thus they do not cause the inflammation. This is a slow process. It takes six months to a year before you can get to the dose that works and then it starts showing any benefit. However, unlike medications, which can only control the symptoms, desensitization provides the only possibility of a “cure” for the underlying problem by inducing immune tolerance to the allergens.
How Are Allergy Shots Given?
Since the final dose of allergy injections may be many hundred times more than the amount used for skin tests, it is necessary to build up gradually. This usually takes six to eight months, sometimes longer, of weekly injections in increasing doses. The build up time can be halved if you can take the injections twice a week. Once you are on maintenance dose, the injections are given every week. During the build up phase you will need to see the doctor every two months and thereafter every three months. After a year or two, as you get better, and don’t need prescription meds, the doctor will see you every six months. Summary instructions for the injections are enclosed with the extract and if you, or the physician giving the injections, have any questions, please call us. Detailed safety instructions for patients and for physicians and nurses giving allergy injections are on our website ( (asthmaweb.com) under the title ‘allergy injections’ in the patient education tab.
What Are The Reactions?
The allergy injection dosage schedule is designed to decrease the chances of serious reaction. An overdose of allergen may produce a generalized reaction, including hives, swelling, breathing difficulty, asthma, drop in blood pressure, which if uncontrolled can be fatal. Thus, we start with a dose you can tolerate and increase slowly as your protection builds up. However, the potential for a serious reaction is always there. Therefore, we insist that you get these injections in a hospital, clinic or at a physician’s office where emergency medications and equipment are available. Most serious reactions occur within the first 20-25 minutes after the injection is given. It is reasonably safe to go home after 30 minutes, if there has been no problem. A ‘mosquito bite’ type itchy red swelling up to 2 inches in diameter at the site of inj. is an acceptable reaction if there are no other symptoms. If the reaction is any larger, please tell the nurse giving the injection.
With the first few injections, you may notice increase in allergy symptoms that evening or the next day. This usually goes away as the protection builds up.
What If I Want To Get My Injections At Home?
Even though the relative risk of reaction becomes less with ongoing injections, it never becomes zero. Therefore, these injections must ALWAYS be taken in a medical office. You are assuming all the risks discussed above if, despite our advice, you insist on getting the injections anywhere outside of a medical setting.
Are There Any Long-term Side Effects?
Besides the reaction risk, there are no known side effects like major organ damage, immune problems or cancer, etc., from allergy injections.
How Long Will I Need Them?
Although many patients notice improvements within the first few weeks, it may take a year to 18 months before the injections start helping. If they don’t help by then, they should be stopped. If they do help, the treatment program usually lasts three to five years, sometimes much longer.
How Do I Store The Vaccine Bottle?
The vaccine bottle should be stored in a refrigerator (not freezer) as the vaccine deteriorates faster at room temperature. But 2-3 days out of the refrigerator will not hurt anything.
What Does The Date Of Expiration On The Vaccine Mean?
Allergy vaccines deteriorate with time. Therefore, they should be replaced after the date of expiration. It is not dangerous to use them longer, but you lose the protection and so there is increased risk of reaction from the next bottle of new vaccine.
What If I Am Sick On The Day My Injection Is Due?
If you have had a cold or upper respiratory infection with fever, the injection should be delayed until a couple of days after acute symptoms, especially fever, are gone. If your allergies or asthma are flared up, you should wait until it settles down. If you have other serious illness or have been started on any new medication (especially beta blockers, call us before your next injection.
What If I Have More Questions?