Immunotherapy with Allergens (Allergy Shots)

The objective of immunotherapy with allergens is to change the allergic response by inducing immunological tolerance. A patient with allergies has symptoms when they are exposed to the relevant allergen. Immunotherapy uses a larger quantity of the allergen, in combination with a different route of entry into the body. This modifies the immune system's abnormal response, causing it to develop a tolerance to the allergen instead of inflammation and allergic symptoms. 

Immunotherapy was originally administered by subcutaneous injection.There are currently liquids or fast-dissolving tablets that can be used in sublingual immunotherapy for certain allergens.

Subcutaneously injected treatments are administered every 4 or 8 weeks; sublingual treatments must be administered daily. This is generally continued over a period of 3 to 5 years. Many patients experience a prolonged protective effect after that period, so an assessment may be made of stopping the immunotherapy. 

Who might need immunotherapy with allergens (allergy shots)? 

Immunotherapy is indicated for patients with allergic rhinoconjunctivitis or allergic asthma who:

• Have symptoms that are not well controlled with drugs or avoidance measures.
• Require high doses of medications, multiple medications, or both, to control the condition.
• Experience adverse reactions to the medications.
• Want to avoid long-term use of pharmacological treatments.

Immunotherapy with hymenoptera venom is indicated for individuals who experience a severe generalised reaction to bee or wasp stings.

Risks

Immunotherapy is generally safe and well tolerated when used in suitably selected patients. Even so, localised and generalised reactions can occur. 

The most frequent reactions are localised ones, such as redness or itching at the injection site. These reactions are most likely to occur during the first administration of the treatment, which is why immunotherapy starts at the Allergology Department and, if well tolerated, can be continued on an outpatient basis.