Allergen immunotherapy

Traditionally administered to patients subcutaneously , but rapidly dissolving tablets for sublingual administration has been approved for treatment of grass and ragweed allergies.

In subcutaneous immunotherapy, the patient receives the offending allergen or possibly allergens in increasing concentrations, until a maintenance dose is achieved.

In sublingual immunotherapy a fixed dose of the allergen is delivered 12-16 weeks before the anticipated start of the allergic season.

This maintenance dose continues for several years.

• Immunotherapy down regulates the allergic response in an allergic-specific manner.

Such immunotherapy has efficacy in controlling allergic rhinitis, allergic asthma, and allergic conjunctivitis.

With immunotherapy, unlike pharmacotherapy, the anti-allergic affects persist after the discontinuation of treatment.

Therapeutic effects of allergen immunotherapy may persist for at least three years after discontinuing treatment.

Disadvantages of subcutaneous immunotherapy is that as a dose of allergen is being built up, injections are required once or twice weekly, and for maintenance therapy monthly.

Subcutaneous injections are generally continued for at least three years.

Subcutaneous immunotherapy is associated with systemic reaction risk, which occurs in 0.1% ejection visits, and in rare cases can lead to life-threatening anaphylaxis with one reaction for 1 million injection visits.

Comparisons of sublingual immunotherapy and subcutaneous immunotherapy suggests that the latter is more effective for symptom relief.

Sublingual immunotherapy is however safer, with fewer reported anaphylactic reactions.

Sublingual immunotherapy requires daily treatment, and adherence to therapy is lower than with subcutaneous therapy. Sublingual immunotherapy can be given at home after the first dose