New forms of allergy immunotherapy for rhinitis and asthma.

Subcutaneous immunotherapy (SCIT) has been proven to be clinically effective in the treatment of allergic rhinitis and asthma. Not only does it reduce symptoms during the course of treatment, but because of modification in the immune response to the administered allergen, there is persistence of improvement for years after discontinuation of a successful course of therapy. A drawback of SCIT is the potential for reactions to the injections. To reduce this risk, a prolonged course of build-up in dose is required and for reasons of safety injections must be administered in a facility prepared to treat the possible systemic reactions. Furthermore, to achieve the persisting benefit, a prolonged administration of the highest dose is required. The perception is that the inconvenience, expense, safety concerns, and dislike for injections all combine to cause SCIT to be used in only a small percentage of patients who would benefit from the treatment. Therefore, a number of new approaches are being investigated that overcome the problems of safety and inconvenience, either by alternative methods of administering the currently available extracts or by modifying the allergens to reduce reactivity with IgE while preserving the potential to induce favorable immunologic changes.