Allergy Shots (Subcutaneous Immunotherapy)

Time commitment:

A series of 'build-up' shots is given upon first starting immunotherapy. These are to be administered once a week, until maintenance is reached.

See the environmental and venom shot cards for their respective times.

Environmental shots:

Build-up will take about 20 weeks, and maintenance shots are given every 4 weeks for 3 to 5 years.

Venom shots:

Build-up will take about 8 weeks. Maintenance shots are given every 4 weeks for the first year, every 6 weeks for the second year, and then every 8 weeks for the third, fourth and fifth years.

Looking for sublingual immunotherapy (SLIT)?

All content below is for subcutaneous immunotherapy (SCIT). Click here for SLIT information.

  • Who should get allergy shots?

    • Proven to have allergies with collaborative history and positive skin tests or blood tests
    • Severe allergic rhinoconjunctivitis (nose/eye symptoms) for 2 or more years not managed by optimal allergen avoidance and medication
    • Some cases of allergic asthma. There must be a clear temporal association between allergen exposure and signs and symptoms of asthma. Symptoms should be occurring during 2 or more allergen seasons during successive years. Regular use of anti-inflammatory medications such as inhaled steroids will suppress symptoms in most patients. Allergen avoidance measures must be properly instituted
    • Allergy to venom (from stinging insects) (see venom allergy information)

  • Who should not?

    • Patients whose history, physical exam, or laboratory studies do not support true allergies despite positive skin tests or blood tests
    • Rhinitis (runny, stuffy nose), Asthma or Insect Reactions NOT due to allergies
    • For treatment of food allergies, eczema or hives
    • Severe uncontrolled asthma
    • Children less than 5 years of age
    • Previous properly administered allergy shots that were not successful
    • No reduction of symptoms after 2 years of allergen injections
    • Allergen injections have been given longer than 5 years
    • Patients on beta-blockers (ie. Inderal, Propranolol, Metoprolol, Acebutolol, etc)
How do THE shots work? YOu are given increasing amounts of what you are allergic to, in order to build up a "tolerance" to it (desensitization)

How Are the Shots Given?
  • Injections are given in the outside upper arm (not in the muscle)
  • Start with tiny dose of what you are allergic to and then gradually build up weekly until a dose called the “maintenance dose” is reached (given every 3-4 weeks)
  • Keep allergy shots vials refrigerated
  • Shots are given by doctor or trained nurse in an office where medications to treat reactions are available
Before Each Injection: 

  • Avoid vigorous exercise or overheating for 2-3 hours prior to injection. Exercise / heat increases the absorption of the allergen (substance you are allergic to) which can increase the risk of reactions

  • Postpone the injection if ill, fever or flare of asthma symptoms

  • Inform doctor if you become pregnant (dose should be reduced if on maintenance or stopped if building up)

  • Inform the nurse or doctor of any reactions that occurred after the last injection

  • Inform the nurse or doctor of any new medications or change in health status

  • Identify your name and dose from vial (make sure you get the correct shot)
After Each Injection: 

  • You must wait at least 30 minutes in the doctor’s office before leaving, so you can be treated if you have a reaction

  • Report any unusual reaction to the nurse or doctor before leaving the office

After you leave the office:

  • Avoid exercise or overheating for a few hours after injection given

  • Carry an antihistamine to take only if necessary for mild reactions

  • If the reaction is severe, go to the emergency
Side Effects: 

Local Reactions (more common): swelling, itchiness, redness around site of injection

  • <4cm is normal for most things, with venom shots you can expect lumps <10cm

  • If >4 cm (>10cm for venoms) or lasts >24hrs, inform the doctor’s office before next injection is given

  • Can use ice or antihistamines for larger lumps

Generalized Reactions (less common): shortness of breath, wheezing, cough, tightness of chest or throat, generalized itching, hives, faintness, flushing, perspiration, nausea, vomiting, passing out

  • Usually occurs within 30 minutes which is why you must wait that long in a doctor’s office after each shot, so that you can be treated if any of the above occur

All immunotherapy patients must commit to staying the full 30 minutes after each shot, otherwise you will not receive your shot at that appointment.
Click for immunotherapy information for health care workers.

Created by Dr. Ellie Tsai MD, FRCPC, Kingston Allergy and Asthma, 613-546-6673