Allergy Shot FAQs

These are the most frequently asked questions that we receive regarding allergy shots. If your question is not answered here, or if you require further information, please contact us.

Why do I have to wait 30 minutes after receiving my allergy shot?

Although there is a low risk of severe reactions, life-threatening and potentially fatal reactions can or may occur. The majority of severe reactions from allergy shots occur within 30 minutes after an injection. If you were to have such a reaction, we are fully equipped to deal with an emergency. The length of time that you have been on allergy shots does not determine whether or not you will have a severe reaction. People who have been on allergy shots for years may also be at risk of having a severe reaction. These reactions are referred to as anaphylaxis.

How can I tell if I’m having an allergic reaction?

If you experience the following signs and symptoms of anaphylaxis while still in the care of your health care provider, notify them immediately. If you are not still in the presence of your health care provider, calls 911or go to your nearest Emergency Department immediately.

• Face — itchy eyes or nose, flushed face, swelling of tongue and lips, metallic taste

• Skin — itchiness, redness, hives, swelling of skin anywhere on the body

• Throat — itchiness, tightness, hoarseness, hacking cough, difficulty swallowing, choking

• Lungs — difficulty breathing, shortness of breath, repetitive coughing, wheezing

• Stomach — vomiting, nausea, stomach pain, diarrhea

• General — dizziness, unsteadiness, drowsiness, sense of impending doom, loss of consciousness, hypotension

A mild reaction may involve some redness, itchiness and/or swelling at the injection site or mild sneezing and nasal stuffiness or clear discharge. Swelling, itchiness and redness may be treated by applying a cold pack and/or taking an antihistamine tablet. An antihistamine tablet may also help ease nasal stuffiness or discharge.  It is important to tell your health care provider about your reaction when you get your next allergy shot. If you are unsure about how severe your reaction is, seek medical attention immediately.

I am going on vacation. What should I do about my allergy shots?

If you know you are going to be away for a period of time, inform your healthcare provider.  Depending on the length of time you are away, your dosing schedule may need to be altered. If you are going to be away for weeks/months at a time, locate a healthcare provider where you will be travelling and request that your allergy shots are administered there. You will need to transport your serum(s) in a cooler kept between 2ºC and 8ºC. Serums must be placed in refrigeration upon arrival to your new destination.

How long do I have to stay on allergy shots?

Once you start allergy shots, you will be assessed on a regular basis to determine your response to the injections. If you have responded well to the treatment, the decision to discontinue is generally make after the initial period of 3–5 years. Some patients do well after discontinuing allergy shots, whereas others relapse back to where they were prior to starting treatment. The decision to continue or discontinue allergy shots should be made in consultation with your Allergist. If you are on venom allergy shots, your treatment will most likely be lifelong.

How effective are allergy shots?

Double blind placebo-controlled studies have consistently demonstrated the efficacy of allergen immunotherapy over placebo treated subjects. The efficacy of venom immunotherapy is by far the most effective therapy in modern medicine (>99 % success rate). The efficacy of pollen immunotherapy is also highly efficacious (>90%), followed by dust mites (>75 %). The role of cat immunotherapy has also been shown to be superior to placebo. Immunotherapy with alternaria and cladosporium has also demonstrated to be superior to that of a placebo treated group.

Why do I need two extracts? Can they be combined into one?

Some allergens work well together in an extract, whereas others, when mixed, can denature/destroy certain components of the extract. Over time, this can affect the potency of the extract.

Do I need to make an appointment to schedule my allergy shots?

You do not need to make an appointment to receive your allergy shot(s), however allergy shots are only given on certain days and times. Please see the shot schedule (link) for an up-to-date schedule for allergy shots. If you receive your injection here, you must be prepared to wait for 30 minutes after the injection has been given in order to ensure you do not have a reaction.

Many family medicine practices also give allergy shots to their patients. If that option would be more convenient, please make sure this is acceptable to your physician, and then make arrangements with us to have your extract delivered to the correct office.

What do I take to my first appointment?

Please bring your health card and a list of any medications you are currently taking. Allergy testing is done on the arms, so we also suggest that, when possible, you wear a short-sleeved shirt or a top where the sleeves push or roll up to your shoulder. Please do not wear scented products as some patients are sensitive and can easily react.

When should I start to feel some relief after starting allergy shots?

For some people, a decrease in symptoms is seen during the build-up phase; for others, it may take as long as 12 months on the maintenance dose. If you have had no improvement after a year of maintenance allergy shots, your allergist will explore potential reasons for this and discuss other treatment options with you.

Can I take allergy medication before visiting the office for testing?

No. In order to accurately test you for allergies, antihistamines should not be taken for 2 days (48 hours) before your appointment. Other medications may be taken, including nasal sprays and those medications needed for asthma. If you are unsure about a particular medication, please call our office and check with us.

Can I take herbal supplements or other natural herbal remedies if I have allergies?

We encourage patients to consult their allergist and/or primary health care provider before taking any natural health care supplement or remedy.

Many health supplements today are actually a combination of ingredients, any one of which could pose a problem for a person who has allergies or is taking other medication. For example, a popular herbal remedy called Echinacea may provoke a physical reaction or aggravated symptoms for persons with ragweed allergies. The reason is that ragweed is often part of the Echinacea mixture sold in health food stores and pharmacies.

Another example is that of herbal diet remedies. Many herbal diet products contain ingredients that can be damaging to heart health or which may conflict with heart medication.

As yet, there is no national production or regulatory standards for herbal or natural health care products in Canada. There is also a great deal that is not yet known about how herbal products interact with pharmaceutical medications. If you are interested in taking a herbal product, consult your health care provider first.

Are there other medications that should not be taken with allergy shots?

Yes. Ensure your allergist knows what medications you are taking on an ongoing basis. This means keeping your records up-to-date when you have your annual check-up, and ensuring that both your allergist and primary health care provider are advised of any new medication you may be taking, as soon as the medication is prescribed.