Clinical efficacy and safety of local nasal immunotherapy.

Local nasal immunotherapy represents an alternative route of allergen administration. It was proposed to overcome the risk of systemic reactions rarely reported during the traditional subcutaneous immunotherapy. Some studies carried out in the past generally showed good efficacy but poor tolerability. The aqueous extracts mostly used in these studies carry some drawbacks such as the volume effect, self-digestion and the difficulty of administering reproducible dosages. The recent availability of allergen extracts in powder form has led to better stability and standardization. The studies carried out with these freeze-dried allergens showed clinical efficacy and good tolerability in perennial (mite, cat) and seasonal (grass, birch, Parietaria) allergic rhinitis. According to these findings this new local nasal immunotherapy with extract in powder form represents a suitable alternative to the traditional immunotherapy in the treatment of allergic rhinitis.