Nasal mucosa is heavily exposed to inflammatory and allergic stimuli, rhinitis being the most common form of allergic respiratory disease. The nose is an easily accessible organ and a good model for the study of allergies as it makes it possible to monitor the effects of specific challenges as well as therapeutic interventions, namely specific immunotherapy (SIT). Injectable, nasal or sublingual SIT are useful therapeutic strategies in the management of allergic rhinitis patients. Monitoring the evolution of parameters such as clinical scores, nasal peak flow variation or drug requirements during SIT provides important information on its clinical efficacy. Laboratory measurement of tryptase and eosinophil cationic protein in the target organ after specific nasal provocation makes it possible to record changes in the release of mast cell and eosinophil mediators, thus providing objective evidence of the immunological efficacy of this therapy on these cell populations and providing data which eventually will contribute to a better understanding of the multiple mechanisms of action of allergen desensitization therapy.